JP6977403B2 - Method for manufacturing lithium negative electrode complex - Google Patents

Description

The present invention relates to a method for producing a lithium negative electrode composite by forming a lithium layer on a negative electrode active material layer.

The lithium ion secondary battery is a secondary battery having a high charge / discharge capacity and capable of increasing output. Lithium-ion secondary batteries are currently mainly used as a power source for portable electronic devices, and are expected to be a power source for electric vehicles, which are expected to become widespread in the future. The lithium ion secondary battery has an active material capable of adsorbing and releasing lithium in the positive electrode and the negative electrode, respectively. Then, the lithium ion, which is a charge carrier, moves in the electrolytic solution existing between the two electrodes, so that the lithium ion secondary battery operates.

As a negative electrode active material used for a negative electrode of a lithium ion secondary battery, a technique of using a negative electrode active material containing Si or Sn is known. Theoretically, Si and Sn have a higher lithium ion occlusion capacity per element than negative electrode active materials such as graphite. Therefore, it is considered that the capacity of the lithium ion secondary battery can be increased by selecting this type of negative electrode active material.

For example, Patent Document 1 and Patent Document 2 describe a lithium ion secondary battery in which the negative electrode active material is silicon. Patent Document 3 and Patent Document 4 describe a lithium ion secondary battery in which the negative electrode active material is SiO.

In Patent Document 5, _{a layered silicon compound containing CaSi 2} as a main component and layered polysilane from which Ca has been removed is synthesized by reacting CaSi 2 with an acid, and the layered silicon compound is heated at 300 ° C. or higher to release hydrogen. It describes that the material was manufactured and that the lithium ion secondary battery includes the silicon material as a negative electrode active material.
In Cited Document 6, the negative electrode active material is at least one selected from the group consisting of Si and Sn, and at least one selected from the group consisting of V, Fe, Co, Ni, Cu, Ag and Sb. An electrode for a lithium secondary battery, which is a composite powder composed of a certain B component, is disclosed.

Japanese Unexamined Patent Publication No. 2014-203595 Japanese Unexamined Patent Publication No. 2015-57767 JP-A-2015-185509 JP-A-2015-179625 International Publication No. 2014/08608 Japanese Unexamined Patent Publication No. 2008-305608

By the way, it is known that the negative electrode active material containing the above-mentioned Si, Sn and the like has a high capacity but also a large irreversible capacity. In order to cancel the irreversible capacity of the negative electrode active material, the inventor of the present invention considered to introduce lithium ions in an amount corresponding to the irreversible capacity into the negative electrode active material in advance. Hereinafter, the introduction of lithium ions into the negative electrode active material is referred to as doping with lithium.

As a lithium doping method, as disclosed in Patent Document 5, a method of manufacturing a lithium battery for doping using a negative electrode and metallic lithium as a counter electrode and doping the negative electrode with lithium is known. There is. Hereinafter, this doping method is referred to as an electrical doping method. In the electrical doping method, by charging the above-mentioned lithium battery for doping, lithium ions at the counter electrode are transferred to the negative electrode, and lithium is doped into the negative electrode. The lithium-doped negative electrode is removed from the lithium battery for doping and used as a negative electrode for a lithium-ion secondary battery.

Although such an electrical doping method is effective as a lithium doping method, it requires a large amount of man-hours, and is therefore a practical industrial method for producing a large number of lithium ion secondary batteries in a relatively short time. Not the target.

As another lithium doping method, as disclosed in Patent Document 6, a lithium layer is further formed on the negative electrode active material layer formed on one side of the current collector, and lithium ions are directly transferred from the lithium layer to the negative electrode active material. A method of doping has also been proposed. The lithium layer is formed by rolling a lithium body into a foil shape or a plate shape. Hereinafter, this kind of doping method is referred to as a direct doping method. If the direct doping method is adopted, there is a possibility that the man-hours required for lithium doping can be reduced.

However, at present, sufficient studies have not been made on a method for producing a lithium negative electrode complex used in such a direct doping method, that is, a composite in which a lithium layer is formed on a negative electrode active material layer of a negative electrode. , A method for producing a lithium negative electrode composite suitable for the direct doping method has been desired.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a new method for forming a lithium layer on a negative electrode active material layer to produce a lithium negative electrode composite suitable for a direct doping method. And.

The inventor of the present invention has actually produced a lithium negative electrode complex for the direct doping method under various conditions. Then, as one of the problems in manufacturing the lithium negative electrode composite, attention was paid to the difference in elongation deformation between the lithium layer and the negative electrode active material layer.

As a method of forming a lithium layer on the negative electrode active material layer, a method of crimping a lithium body on the negative electrode active material layer can be considered. Specifically, the lithium layer can be formed on the negative electrode active material layer by pressing the laminated body in which the lithium body is arranged on the negative electrode active material layer of the negative electrode in the direction in which the negative electrode and the lithium body are in close contact with each other. Hereinafter, if necessary, the laminated body of the negative electrode and the lithium body is simply referred to as a laminated body. The lithium foil and the lithium plate described later can be read as a lithium body.
Reference 6 discloses a method of crimping a thin lithium foil onto a negative electrode active material using a roll press machine. From the viewpoint of efficiently producing the lithium negative electrode complex, it is considered very effective to use a roll press machine for the crimping.

By the way, the inventor of the present invention has aimed to dope a large amount of lithium into the negative electrode active material layer. In this case, if a lithium plate thicker than the lithium foil is pressure-bonded to the negative electrode active material layer to form a thick lithium layer, the amount of lithium that can be doped into the negative electrode active material layer also increases. However, when the inventor of the present invention actually crimps a lithium plate to the negative electrode active material layer using a roll press machine, problems such as breakage or breakage of the negative electrode active material layer occur, and the lithium ion secondary battery has a problem. It was not possible to obtain a usable lithium negative electrode composite. The present inventor speculates the reason as follows.

The lithium body is very soft and has the property of being easily stretched and deformed. On the other hand, the negative electrode active material layer is harder than the lithium body and is not easily elongated and deformed. Therefore, when the lithium body is crimped to the negative electrode active material layer, it is considered that the larger the amount of elongation and deformation of the lithium body, the larger the force acting on the negative electrode active material layer. If the force acting on the negative electrode active material layer is excessive, the negative electrode active material layer may be damaged.

When the load acting on the lithium body from the roll press machine in the thickness direction is a predetermined magnitude, the amount of elongation deformation of the lithium body is related to the thickness of the lithium body, and when a thin lithium foil is used as the lithium body. The amount of change in the thickness of the lithium body before and after the roll press is significantly different from that of using a thick lithium plate. That is, in the case of roll pressing with a predetermined load, it can be said that the larger the thickness of the lithium body, the larger the amount of deformation of the lithium body. It is considered that if the amount of deformation of the lithium body is large, the force acting on the negative electrode active material layer that is crimped to the lithium body is also large, and the negative electrode active material layer is easily damaged.

Here, the roll press machine has a roll portion composed of two rolls. The roll portion applies a linear pressure to the laminated body passing between the two rolls in the thickness direction of the laminated body along the axial direction of the roll. At the same time, the roll portion conveys the object in the direction orthogonal to the axial direction of the roll and the thickness direction of the laminated body by the rotation of the roll. Hereinafter, if necessary, the axial direction of the roll is simply referred to as an axial direction, and the direction orthogonal to the axial direction and the thickness direction of the laminated body is simply referred to as a rolling direction.
When the lithium plate is crimped onto the negative electrode active material layer by a roll press machine, the roll portion is in the direction in which the negative electrode and the lithium plate are in close contact with the laminated body of the negative electrode and the lithium plate, that is, the thickness of the laminated body. A linear pressure in the radial direction is applied along the axial direction, and the laminated body that has passed through the roll portion is conveyed in the rolling direction. The laminated body at the time of transportation is stretched in the rolling direction by the roll portion. That is, the force acting on the laminated body from the roll portion at this time is two forces, a linear pressure in the thickness direction of the laminated body and a force for pulling and / or extending the laminated body along the rolling direction of the laminated body. It is roughly divided.

Among the above-mentioned two forces by the roll press machine, the above-mentioned force for pulling and / or extending the laminated body along the rolling direction of the laminated body is greatly related to the direction in which the laminated body is extended and deformed. That is, when the laminated body is pressed by the roll press machine, the laminated body mainly extends and deforms in the rolling direction. In other words, at this time, the extending and deforming directions of the laminated body are not dispersed, and are almost only in the rolling direction. Focusing on the lithium plate in the laminated body, it is considered that the overall elongation deformation amount of the lithium plate tends to be excessive because the elongation deformation direction of the lithium plate is not dispersed and is limited to the rolling direction. As a result, it is considered that the negative electrode active material layer crimped to the lithium plate is likely to be damaged.
That is, one of the causes of the above-mentioned damage to the negative electrode active material layer is that a thick lithium plate is used as the lithium body to be pressure-bonded to the negative electrode active material layer, and a large force is applied to the laminated body in one direction. It is thought that there is something in it.

Based on the above assumptions, the present inventor has made extensive studies to eliminate the cause of damage to the negative electrode active material layer, and invented the present invention.
That is, the method for producing a lithium negative electrode complex of the present invention is:
A method for producing a lithium negative electrode composite having a negative electrode having a negative electrode active material layer formed on the surface of the current collector and the current collector, and a lithium layer formed on the negative electrode active material layer. There,
It has a pressing process in which a surface pressure is applied to a laminate in which a lithium plate is arranged on the negative electrode in a direction in which the negative electrode and the lithium plate are in close contact with each other by using a press machine.
In the pressing step, a plate material is interposed between the press machine and the lithium plate, and a release agent is interposed between the lithium plate and the plate material, which is a method for producing a lithium negative electrode composite.

The method for producing a lithium negative electrode composite of the present invention is a new method for producing a lithium negative electrode composite suitable for a direct doping method by crimping a lithium plate to a negative electrode active material layer to form a lithium layer.

It is explanatory drawing which shows typically the state that the lithium negative electrode complex of Example 1 is manufactured by pressing a laminated body with a press machine. It is an enlarged view of the main part which enlarged the part of the laminated body in FIG. It is explanatory drawing which shows typically the lithium negative electrode complex of Example 1. FIG.

Hereinafter, the best mode for carrying out the present invention will be described. Unless otherwise specified, the numerical range "x to y" described in the present specification includes the lower limit x and the upper limit y. Then, a numerical range can be configured by arbitrarily combining these upper limit values and lower limit values, as well as the numerical values listed in the examples. Further, the numerical value arbitrarily selected from the numerical range can be set as the upper limit and the lower limit of the new numerical range.

The method for producing a lithium negative electrode complex of the present invention is:
A method for producing a lithium negative electrode composite having a negative electrode having a negative electrode active material layer formed on the surface of the current collector and the current collector, and a lithium layer formed on the negative electrode active material layer. There,
It has a pressing process in which a surface pressure is applied to a laminate in which a lithium plate is arranged on the negative electrode in a direction in which the negative electrode and the lithium plate are in close contact with each other by using a press machine.
In the pressing step, a plate material is interposed between the press machine and the lithium plate, and a release agent is interposed between the lithium plate and the plate material, which is a method for producing a lithium negative electrode composite.

That is, in the method for manufacturing a lithium negative electrode composite of the present invention, a surface pressure is applied instead of a linear pressure to a laminate in which a lithium plate is arranged on the negative electrode.

In the method for producing a lithium negative electrode composite of the present invention, a surface pressure is applied to a laminated body to disperse the elongation deformation directions of the lithium plate in multiple directions and suppress excessive elongation deformation in one direction of the lithium plate. Can be. By doing so, it is possible to crimp the thick lithium plate to the negative electrode active material layer without damage. Therefore, according to the method for producing a lithium negative electrode composite of the present invention, it is possible to produce a lithium negative electrode composite that can be doped with a large amount of lithium by a direct doping method while suppressing damage to the negative electrode active material layer. be.

The method for producing the lithium negative electrode composite of the present invention may have the above-mentioned pressing step, and may have other steps. For example, a negative electrode forming step of forming a negative electrode active material layer on the current collector may be included before the pressing step.
Hereinafter, the method for producing a lithium negative electrode composite of the present invention may be referred to as the production method of the present invention, if necessary, and the lithium negative electrode composite obtained by the production method of the present invention may be referred to as the lithium negative electrode composite of the present invention. May be called. Further, a negative electrode in which the negative electrode active material layer is doped with lithium is referred to as a lithium-doped negative electrode, and among these, a lithium-doped negative electrode obtained by doping the negative electrode active material layer in the lithium negative electrode composite of the present invention with lithium in the lithium layer. Is referred to as a lithium-doped negative electrode of the present invention, if necessary.

The negative electrode may be any as long as it has a current collector and a negative electrode active material layer formed on the surface of the current collector, and is a single-layer type in which the negative electrode active material layer is formed only on one surface of the current collector. It may be a two-layer type having a negative electrode active material layer formed on both sides of the current collector. In the negative electrode forming step, a general method for forming a negative electrode active material layer can be used. The details of the negative electrode forming step and the negative electrode will be described later.

The pressing step is a step of applying a surface pressure to the laminate in which the lithium plate is arranged on the negative electrode in the direction in which the negative electrode and the lithium plate are in close contact with each other by using a press machine.

As the press machine, one that can apply a surface pressure to the laminated body in the direction in which the negative electrode and the lithium plate are in close contact with each other can be used. Since the roll press machine described above applies linear pressure to the laminated body instead of surface pressure, it is excluded from the press machine of the present invention.
Specifically, the press machine has a first press die and a second press die arranged to face each other, and a drive unit for reciprocating the first press die and / or the second press die with respect to the other. , Anything can be used as long as the surface pressure can be applied to the laminated body between the first press mold and the second press mold. For the convenience of applying surface pressure to the laminate, the first press surface, which is the surface on the second press die side in the first press die, and the second press surface, which is the surface on the first press die side in the second press die. Is preferably flat. Further, it is preferable that the first press die and the second press die reciprocate relatively so that the first press surface and the second press surface are parallel to each other.

In the lithium negative electrode composite of the present invention, in the pressing process, a plate material is interposed between the press machine and the lithium plate, and a release agent is interposed between the lithium plate and the plate material. Specifically, the plate material may be arranged on the surface of the laminate on the lithium plate side, and a release agent may be interposed between the lithium plate and the plate material. The material, shape, and thickness of the plate material are not particularly limited, but for the convenience of applying surface pressure to the laminated body, it is preferably in the shape of a plate, a sheet, a film, or the like having a flat surface.

For example, when the negative electrode is the single-layer type described above, each element in the pressing process is arranged in the order of the first press mold, the plate material, the release agent, the lithium plate, the negative electrode, and the second press mold. Here, since lithium is soft and easily deformed as described above, when the first press mold is brought into direct contact with the lithium plate and the pressing process is performed, the lithium plate is firmly adhered to the first press mold. In this case, when the laminated body after pressing, that is, the lithium negative electrode composite is removed from the press machine, it is difficult to remove the lithium layer from the first press mold, and the lithium layer may be deformed or damaged. When the lithium layer is damaged, the thickness of the lithium layer on the negative electrode active material layer becomes uneven, or a portion where the lithium layer is not formed is formed on the negative electrode active material layer. When such a lithium negative electrode complex is used in the direct doping method, lithium is not uniformly doped in the negative electrode active material, and it is difficult to suitably perform lithium doping. That is, it cannot be said that the lithium negative electrode complex in which the lithium layer is damaged is suitable for the direct doping method.

According to the manufacturing method of the present invention, by interposing the plate material and the release agent between the first press mold and the lithium plate, it is possible to avoid strong adhesion of the lithium plate to the first press mold during pressing. Since the release agent is interposed between the plate material and the lithium plate, strong adhesion of the lithium plate to the plate material is also suppressed. As a result, according to the production method of the present invention, it is possible to obtain a lithium negative electrode complex in which damage to the lithium layer is suppressed. In this way, interposing a plate material and a release agent between the first press mold and the lithium plate to avoid strong adhesion between the lithium plate and the first press mold is extremely difficult in the manufacture of the lithium negative electrode composite. It is useful for.

Even when a release agent is directly interposed between the first press mold and the lithium plate without using a plate material, the strong adhesion of the lithium plate to the first press mold can be suppressed, and the lithium layer may be damaged. It is possible to produce a suppressed lithium negative electrode complex. However, in this case, the release agent remains in the first press mold after pressing. The release agent is in a state of being unevenly adhered to the first press surface of the first press mold, and the release agent and the first press mold in this state cannot withstand use. Therefore, in this case, a step of removing the remaining release agent from the first press die is required separately, and it is difficult to continuously and repeatedly use the first press die. That is, in this case, it can be said that it is difficult to manufacture the lithium negative electrode complex with high manufacturing efficiency.

On the other hand, according to the manufacturing method of the present invention in which a plate material is used and a release agent is interposed between the plate material and the lithium plate, the first press mold of the press machine does not come into direct contact with the release agent or the lithium plate. It can be used continuously and repeatedly, and as a result, it is possible to manufacture a lithium negative electrode composite with high manufacturing efficiency.

In the pressing process, the load acting on the laminated body per unit area may be appropriately set according to the specifications of the negative electrode to be manufactured, and is not particularly limited in the present invention.
However, if the load is too small, the lithium plate may not adhere to the negative electrode active material layer, and lithium doping to the negative electrode active material layer may not be performed satisfactorily. Further, if the load is excessive, the amount of elongation and deformation of the lithium plate becomes excessive, and the negative electrode active material layer may be damaged. In view of such circumstances, in the pressing process, the load acting on the laminate per unit area is preferably ⁱⁿ the range of ^{3kN / cm 2 ~50kN / cm 2} , 4kN / cm 2 ~40kN / cm ^It is more preferably in the range of 2 and even more preferably in ^{the range of 5 kN / cm 2 to} 30 kN / cm ^2.

The load in the pressing process is preferably such that the compressibility of the lithium plate before and after the pressing process is 50 to 90%, and more preferably 60 to 85%. .. The compressibility of the lithium plate referred to here is {(bw-aw) / bw when the thickness of the lithium plate before the pressing process is bw and the thickness of the lithium plate after the pressing process, that is, the lithium layer is aw. } It is a value calculated by × 100.

As described above, the plate material is not particularly limited, but for the purpose of reinforcing the lithium plate, it is preferable to select a material having relatively excellent strength and rigidity. Specific examples of the material suitable for the plate material include metals, resins, and ceramics.

Considering that the pressing process is continuously performed, it is preferable to use an inexpensive plate material that can be disposable. Considering the cost and reactivity with lithium, the plate material is preferably made of resin. Considering the handleability in the pressing process, the plate material is more preferably in the form of a sheet or a film having a relatively thin plate thickness. Specific examples of the plate thickness of the plate material include 5 mm or less, 2 mm or less, 1 mm or less, and 0.5 mm or less. The lower limit of the plate thickness is not particularly limited, but 25 μm and 10 μm can be mentioned as the lower limit.
As the resin material for the plate material, for example, polyolefins typified by polyethylene and polypropylene, polyester typified by polyethylene terephthalate and polybutylene terephthalate, and the like are preferably used. Since these are relatively inexpensive and have relatively excellent strength, for example, a lithium plate material composite in which a lithium plate, a release agent, and a plate material are layered is prepared in advance, and the lithium plate material composite is used in the pressing process. When used, it has the advantage that the lithium plate can be reinforced by the plate material.

The release agent is not particularly limited as long as it can be interposed between the plate material and the lithium plate in the pressing process to suppress strong adhesion between the two.
Here, in the present specification, the release agent refers to a material that can exhibit a certain degree of lubricating function and has low fluidity to the extent that it can form a layer between a plate material and a lithium plate.

When the release agent is interposed between the plate material and the lithium plate, the release agent may be integrally provided on the plate material in advance, or may be formed between the lithium plate and the plate material before the pressing process. As described above, the plate material, the release agent, and the lithium plate may be layered to form a lithium plate material composite. In any case, the release agent is preferably formed in a layer between the plate material and the lithium plate. Hereinafter, the layered release agent may be referred to as a release layer, if necessary.
The release layer may be formed directly on the plate material, or may be formed directly on the lithium plate. Considering the deformability of the lithium plate, it is preferable to form a release layer on the plate material and superimpose the lithium plate on the release layer.

The release agent is not particularly limited, but an inorganic powder-based release agent, a carbon-based release agent, or a silicone-based release agent is useful as a release agent. These may be used alone or in combination.

Examples of the inorganic powder-based release agent include inorganic compounds such as alumina, silica, titania, talc, mica, silicon nitride, boron nitride, calcium silicate, molybdenum disulfide, and tungsten disulfide, and powdery ones. can. These inorganic powder-based release agents preferably have a small particle size, more preferably in the range of an average particle size of 5 nm to 1000 nm, further preferably in the range of 8 nm to 200 nm, and further preferably in the range of 10 nm to 100 nm. It is particularly preferable to be inside. In the present specification, the average particle size means the value of D50 in the laser diffraction type particle size distribution measurement.
Particularly preferable inorganic powder-based release agents include silica and alumina in the form of fine particles such as fumed silica and fumed alumina.
Further, as a particularly preferable inorganic powder-based release agent, boron nitride can be mentioned. Examples of the boron nitride include cubic boron nitride (c-BN) and hexagonal boron nitride (h-BN), of which c-BN is particularly preferably used. ..

Examples of the carbon-based release agent include graphite, carbon black, fullerene, carbon nanotubes, cluster diamond, diamond-like carbon, carbon nitride and the like. Of these, diamond-like carbon and carbon nitride are generally used in the form of a film, and are preferably formed in the form of a film on a plate material. Most of the other carbon-based release agents are generally in the form of particles, and may be used as they are in the form of particles, or may be arranged in a film or layer on a plate material if necessary. The particulate carbon-based release agent can be placed on the plate material in the form of particles by a method such as electrostatic coating, or a slurry is formed with an additive such as a solvent or a thickener to form a film on the plate material. It can also be arranged in a shape or a layer. Since carbon black is relatively inexpensive and has excellent performance, it can be particularly preferably used as a carbon-based release agent.

The silicone-based release agent is a compound having a main skeleton due to a siloxane bond, and has various properties mainly derived from the siloxane bond. Among the properties of silicone, the property of being difficult to adhere to the mating material is considered to greatly contribute to pressing the laminate while suppressing the adhesion of the lithium plate to the plate material.

As the silicone-based release agent, it is preferable to select a silicone material that is relatively easily deformed when the release layer is formed, exhibits a certain degree of adhesiveness to the mating material, and is difficult to firmly adhere to the mating material. As such a silicone-based release agent, a silicone resin described later may be used, but it is preferable to use an addition-curing type or peroxide curing type silicone pressure-sensitive adhesive. This type of silicone pressure-sensitive adhesive is used as a pressure-sensitive adhesive for pressure-sensitive adhesive tapes typified by labels and masking tapes because it exhibits an excellent pressure-sensitive pressure-sensitive adhesive effect.

The addition-curing type silicone pressure-sensitive adhesive preferably has a siloxane unit represented by the following general formula (1) as a repeating unit, and may have a linear structure having the repeating unit as a main chain.
R ⁵ _y SiO _{(4-y) x 0.5} (1)
(R ⁵ in the formula is a monovalent or divalent hydrocarbon group having 1 to 20 carbon atoms which may be substituted independently, and y is 1.0 to 3.0.)

Examples of y in the above equation (1) include 1.5 to 2.05.

The number of carbon atoms of the monovalent or divalent hydrocarbon group represented by ^{R 5} in the above formula (1) include a range of 1～14,1～12. Examples of the hydrocarbon group include at least one selected from an alkyl group, an alkenyl group, an aryl group, an aralkyl group or an alkylene group. Two or more of R ⁵ may be an alkenyl group. Specific examples of the alkyl group include a methyl group. Specific examples of the alkenyl group include at least one selected from a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group or a heptenyl group. Specific examples of the aryl group include a phenyl group.

Examples of the addition-curing type silicone pressure-sensitive adhesive include those in which an organopolysiloxane having an alkenyl group and a silicone pressure-sensitive adhesive raw material containing an organohydrogenpolysiloxane are cured by an addition reaction. An addition reaction catalyst may be used to increase the rate of the addition reaction.

When the addition-curable silicone pressure-sensitive adhesive uses the siloxane unit represented by the above formula (1) as a repeating unit, examples of the organopolysiloxane include compounds containing a siloxane unit represented by the following general formula (1-1). Be done.
R ⁶ _y SiO _{(4-y) x 0.5} (1-1)
(In the formula, R ⁶ is an alkenyl group independently, and y is 1.0 to 3.0.)

The organopolysiloxane preferably has a siloxane unit represented by the above general formula (1-1) as a repeating unit, and may have a linear structure having the repeating unit as a main chain. The organopolysiloxane may be linear or may have a branched and / or cyclic partial structure as well as a linear partial structure. The molecular weight of the organopolysiloxane is not particularly limited.

The organohydrogenpolysiloxane has a SiH group in the molecule, and the organic group thereof is not particularly limited. The number of SiH groups in one molecule of organohydrogenpolysiloxane is not particularly limited, and may range from 2 to 300, 3 to 200, and 4 to 150. The SiH groups may react with the alkenyl group R ⁶ in the organopolysiloxane, which contributes to curing of the addition curing type silicone adhesive. Therefore, the number of SiH groups in one molecule of organohydrogenpolysiloxane is preferably 2 or more. The organohydrogenpolysiloxane may be linear or branched.

As raw materials for the addition-curable silicone pressure-sensitive adhesive, KS-774, KS-775, KS-778, KS-779H, KS-847H, KR3700, KR3701, X-40-3237-1, X-40-3240, X-40-3291-1, X-40-3229, X-40-3270, X-40-3306 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), SD4584, SD4585, SD4560, SD4570, SD4600PFC, SD4593, (above) , Toray DouConning Co., Ltd.), TSR1512, TSR1516, XR37-B9204 (all manufactured by Momentive Performance Materials Co., Ltd.) and the like. As the addition-curing type silicone pressure-sensitive adhesive, these may be used alone or in combination of two or more. As a specific combination when two or more kinds of silicone adhesives are used in combination, a combination of KS-847H manufactured by Shin-Etsu Chemical Co., Ltd. and SD4584 manufactured by Toray Industries, Inc. can be mentioned. , Not limited to this.
Further, a release layer may be formed by combining the raw material of the silicone resin described later with the raw material of the silicone pressure-sensitive adhesive. SD4584 manufactured by Toray Industries, Inc. contains a trifunctional or tetrafunctional siloxane unit, and the silicone adhesive obtained by using the raw material exhibits the same characteristics as the silicone resin. However, it is considered that a peeling layer having a good balance between adhesiveness and peelability can be formed.

As the addition reaction catalyst, one that can function as the catalyst for the above-mentioned addition reaction may be used. For example, various platinum-based catalysts such as platinum, platinum compounds, and various complexes of platinum, rhodium-based catalysts such as rhodium chloride, and palladium. , Palladium-based catalysts such as palladium chloride can be exemplified.

The peroxide-curing type silicone pressure-sensitive adhesive is different from the above-mentioned addition-curing type silicone pressure-sensitive adhesive in that it performs a curing reaction of organopolysiloxane in the presence of an organic peroxide. As the organopolysiloxane used as a material for the peroxide-curable silicone pressure-sensitive adhesive, the same organopolysiloxane as described in the above-mentioned addition-curable silicone pressure-sensitive adhesive may be used, but R ⁶ is an alkyl group. Those are preferable.

As the organic peroxide, one that decomposes to generate free oxygen radicals may be used, and is not particularly limited. Examples of organic peroxides that can be used as raw materials for peroxide-curable silicone pressure-sensitive adhesives include dibenzoyl peroxide, 4,4'-dimethylbenzoyl peroxide, and 3,3'-dimethylbenzoyl peroxide. Examples thereof include 2,2'-dimethylbenzoyl peroxide.

In order to form a release layer with each of the above-mentioned silicone pressure-sensitive adhesives, each of the above-mentioned raw materials may be mixed with a solvent such as an organic solvent, if necessary, and applied to a plate material to carry out a curing reaction. Before and after the curing reaction, the silicone pressure-sensitive adhesive or the raw material of the silicone pressure-sensitive adhesive on the plate material may be heated. By heating, it is possible to remove the solvent and accelerate the curing reaction.

As the material of the release layer provided on the plate material, the following silicone resin can also be used in addition to the above-mentioned silicone pressure-sensitive adhesive. As described above, the silicone resin may be used in combination with the silicone adhesive. The release layer containing a silicone resin can exhibit the characteristics of being less likely to be deformed and having lower adhesiveness than the release layer containing a silicone adhesive. The peeling layer containing the silicone adhesive can exhibit the property of having higher tackiness than the peeling layer containing the silicone resin.
Hereinafter, the silicone resin will be described.

As described above, the silicone resin has the property of being relatively hard to be deformed and having low adhesiveness. Specifically, the silicone resin is a bifunctional siloxane unit represented by the following general formula (2), a trifunctional siloxane unit represented by the following general formula (3), or the following general formula (4). ), It is preferable to include a polyorganosiloxane material containing a tetrafunctional siloxane unit.
R ¹ R ² SiO _{(0.5 × 2)} (2)
R ¹ SiO _{(0.5 × 3)} (3)
SiO _{(0.5 × 4)} (4)
(In the formula, R ¹ and R ² are independently any of an alkyl group, a phenyl group, a vinyl group, and an amino group having 1 to 3 carbon atoms. Even if R ¹ and R ² are the same. It may be good or different.)

The polyorganosiloxane material containing any of the siloxane units of the general formulas (2) to (4) can form a relatively hard release layer having a three-dimensional network structure.

Examples of the raw material of the polyorganosiloxane material containing any of the siloxane units of the general formulas (2) to (4) include compounds represented by the following general formulas (2-1) to (4-1), respectively. Be done.
R ¹ R ² Si (OR ³ ) ₂ (2-1)
R ¹ Si (OR ³ ) ₃ (3-1)
Si (OR ³ ) ₄ (4-1)
(In the formula, R ¹ and R ² are each independently H, an alkyl group having 1 to 3 carbon atoms, a phenyl group, a vinyl group, and an amino group. R ³ has 1 to 3 carbon atoms. It is an alkyl group. R ^{1 to} R ³ may be the same or different from each other.)

The raw material of the polyorganosiloxane material is a bifunctional compound represented by the general formula (2-1), a trifunctional compound represented by the general formula (3-1), or the general formula. Any of the tetrafunctional compounds represented by the formula (4-1) may be used, and the proportion of the bifunctional compound, the trifunctional compound and the tetrafunctional compound in the raw material is not particularly limited. .. Of these compounds contained in the raw material, when the proportion of the bifunctional compound is large, the flexibility of the release layer is increased, and when the proportion of the trifunctional compound is large, the release layer is hard and the tetrafunctional compound is used. It is said that the release layer becomes harder when the proportion of the sex compound is large.

Examples of the silicone resin for the release layer include those containing a trifunctional siloxane unit and those containing a trifunctional siloxane unit and a bifunctional siloxane unit. Examples of R ¹ , R ² and R ³ include a methyl group, a propyl group and a phenyl group, respectively. Further, the mass average molecular weight of the silicone resin may be in the range of 300 or more and 30,000 or less, and the residual alkoxy amount in the silicone resin may be in the range of 2% by mass or more and 50% by mass or less.

As raw materials for the silicone resin containing the siloxane unit of the general formula (2), methylhydrogendimethoxysilane, methylhydrogendiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methylethyldimethoxysilane, diethyldimethoxysilane, diethyl. Examples thereof include diethoxysilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, phenylmethyldimethoxysilane, and vinylmethyldimethoxysilane. These are bifunctional alkoxysilanes.

As raw materials for the silicone resin containing the siloxane unit of the general formula (3), KR220L, KR242A, KR271, KR282, KR300, KR311, KC89, KR500, KR212, KR213, KR9218, KR251, KR400, KR255, KR216, KR152 ( (Made by Shin-Etsu Chemical Co., Ltd.), 804RESIN, 805RESIN, 806ARESIN, 840RESIN, SR2400, 3037INTERMEDIATE, 3074INTERMEDIATE, Z-6018, 217FLAKE, 220FLAKE, 233FLAKE, 249FLAKE, 249FLAKE, QP862-14 AY42-163 (above, manufactured by Toray Dow Corning Co., Ltd.), SY231, SY550, SY300, SY409, SY430, IC836 (above, manufactured by Asahi Kasei Wacker Co., Ltd.) can be exemplified. These contain trifunctional alkoxysilanes and / or derivatives thereof.

Examples of the raw material of the silicone resin containing the siloxane unit of the general formula (4) include tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane. In addition, M silicate 51, silicate 35, silicate 45, FR-3 (above, manufactured by Tama Chemical Industry Co., Ltd.), MSI51, ESI40, ESI48, EMCi48 (above, manufactured by Colcourt), MS51, MS56 (above, Mitsubishi Chemical Corporation) (Made by a company) can be illustrated. These contain tetrafunctional alkoxysilanes and / or derivatives thereof.

The silicone resin constituting the release layer is produced by the dehydration condensation reaction of the raw material of the silicone resin, that is, alkoxysilane and / or its derivative. As the raw material of the silicone resin, only one kind of the alkoxysilanes (2-1) to (4-1) and / or a derivative thereof may be used, or two or more kinds thereof may be used in combination.

The method for forming the release layer is not particularly limited, and a known coating method may be used. Further, the thickness of the release layer may be appropriately set according to the thickness of the lithium plate, the thickness of the plate material, the load acting on the laminated body per unit area in the pressing process, and the like.

For the purpose of suppressing the deformation of the lithium plate with higher reliability, it is preferable to use a silicone resin as the release agent. As described above, the silicone resin has a small adhesive force and can be easily peeled off from the lithium plate, so that the adhesive force of the silicone resin can suppress damage to the lithium plate.
On the other hand, when the plate material, the release agent, and the lithium plate are laminated in advance and used as a lithium plate material composite in the pressing process, the lithium plate may fall off from the plate material by using a release agent having a high adhesive strength to some extent. Can be suppressed, and the handleability of the lithium plate material composite is greatly improved. Therefore, in this case, it is particularly preferable to use a silicone pressure-sensitive adhesive as the release agent.

In the method for producing a lithium negative electrode composite of the present invention, the thickness of the lithium plate pressure-bonded onto the negative electrode active material layer, that is, the amount of lithium doped in the negative electrode active material layer is appropriately determined according to the type and amount of the negative electrode active material. Just set it. For example, when a Si-containing negative electrode active material having a large irreversible capacity is used as the negative electrode active material, the amount of lithium doped in the negative electrode active material layer is large enough to cancel the irreversible capacity of the negative electrode active material layer. good. If the amount of lithium required for doping is large, it is necessary to laminate a thick lithium body, that is, a lithium plate on the negative electrode active material layer. However, as described above, according to the production method of the present invention, the negative electrode active material layer The lithium body can be pressure-bonded to the negative electrode active material layer while suppressing damage. That is, the production method of the present invention is particularly useful as a method for producing a lithium negative electrode complex containing a negative electrode active material having a large irreversible capacity.
In the production method of the present invention, the thickness of the lithium plate can be 15 μm or more, 20 μm or more, and 25 μm or more. The upper limit of the thickness of the lithium plate is not particularly limited, and examples thereof include 200 μm and 500 μm.

In the pressing process, it is essential to interpose a release agent between the plate material and the lithium plate, but if necessary, a lubricant may be interposed in addition to the release agent. The lubricant may be placed between the release agent and the lithium plate. The lubricant refers to a lubricant having a higher fluidity than the release agent and a lubricant having a fluidity that cannot be formed as a layer.
As the lubricant, it is preferable to use a lubricant that has good compatibility with a release agent such as a silicone-based release agent and has low reactivity with lithium.

Examples of the lubricant include an aprotic organic solvent. Specifically, it is preferable to use one having a vapor pressure in the range of 0.3 to 65.0 kPa at 20 ° C. or a vapor pressure in the range of 0.5 to 100 kPa at 25 ° C.
Specific examples of the lubricant include pentane, hexane, heptane, octane, nonane, decane, ethylmethylcarbonate, propylene carbonate, dimethylcarbonate, diethylcarbonate, fluoromethylmethylcarbonate, difluoromethylmethylcarbonate, 2,2,2-. Trifluoroethyl methyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, acetonitrile, propionitrile, butyronitrile, acrylonitrile, dimethoxymethane, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetra, 1,2 -Dioxane, 1,3-dioxane, 1,4-dioxane, 2,2-dimethyl-1,3-dioxolane, 2-methyltetrahydropyran, 1,3-dioxolan, N, N-dimethylacetamide, isopropylisocyanate, n -Propyl isocyanate, chloromethylisocyanate, dimethylacetal, diethyl ether, methylisobutylketone, 1,2-dimethoxyethane, 1,2-diethoxyethane, methyl nitate, ethyl nitate, propyl silicate, methyl acetate, ethyl acetate, butyl acetate , Methyl acetate, isopropyl acetate, isobutyl acetate, methyl propionate, vinyl acetate, methyl acrylate, methyl methacrylate, glycidyl methyl ether, epoxy butane, 2-ethyloxylan, oxazole, 2-ethyloxazole, oxazoline, 2-methyl-2- Examples thereof include oxazoline, acetone, methyl ethyl ketone, methyl isobutyl ketone, anhydrous acetic acid, 1-nitropropane, 2-nitropropane, furan, γ-butyrolactone, thiophene, pyridine, 1-methylpyrrolidin, N-methylmorpholin and the like. In the method for producing a lithium negative electrode composite of the present invention, one or a combination of two or more of these aprotic organic solvents may be used as a lubricant.
Of these, at least one selected from hexane, heptane, octane, nonane, decane, methyl isobutyl ketone, ethyl methyl carbonate, and dimethyl carbonate is particularly preferable as a lubricant. These lubricants are used in the electrolytic solution of the lithium ion secondary battery, or even if they are not sufficiently volatilized and are brought into the lithium ion secondary battery, the performance of the lithium ion secondary battery deteriorates. There is an advantage that is difficult to make.

As the lithium plate, a commercially available one may be used, or a commercially available thick lithium plate, that is, a commercially available thick lithium plate, that is, an appropriately rolled lithium plate may be used. That is, the method for producing a lithium negative electrode composite of the present invention may include a lithium plate rolling step for rolling a lithium thick plate to obtain a lithium plate.

As the rolling apparatus used in the lithium plate rolling process, a press machine similar to the above-mentioned press process may be used, or a roll press machine may be used.
The lithium thick plate to be rolled in the lithium plate rolling step may be rolled in a state of being sandwiched between plate materials. In this case, if a release agent is interposed between the plate material and the lithium thick plate, the release agent is interposed between the lithium plate obtained in the lithium plate rolling process and the plate material, and the deformation of the lithium plate is suppressed. At the same time, the plate material can be easily peeled off from the lithium plate. Further, in this case, there is an advantage that a lithium plate laminate in which a plate material, a release agent and a lithium plate are laminated can be produced at the same time by the lithium plate rolling step.

The laminated body after the pressing process, that is, the lithium negative electrode composite of the present invention has a negative electrode active material layer and a lithium layer, and is a precursor of the lithium-doped negative electrode of the present invention in which the negative electrode active material layer is doped with lithium. It can be called a body. The doping of lithium into the negative electrode active material layer gradually progresses even if the lithium negative electrode complex is left as it is. However, the lithium doping rate can be increased by bringing the lithium negative electrode complex into contact with the electrolytic solution.

Specifically, as the electrolytic solution, one containing an organic solvent and a lithium salt may be used. As the organic solvent and the lithium salt, those that can be used as the electrolytic solution for the lithium ion secondary battery described later may be used. The step of bringing the lithium negative electrode complex into contact with the electrolytic solution is called a dope step. By the doping step, the lithium in the lithium layer provided on the negative electrode active material layer is transferred to the negative electrode active material layer. Therefore, in the lithium negative electrode composite after the doping step, the lithium layer is substantially eliminated, and only the negative electrode active material layer having a one-layer structure in which lithium is integrated remains on the current collector. Therefore, the lithium negative electrode complex after the doping step does not need to consider peeling of lithium and the like, and the handleability is improved.

In addition, based on this technical idea, the present invention can also be regarded as an invention relating to a method for manufacturing a lithium-doped negative electrode having the doping step.

In the doping step, the lithium negative electrode composite may be brought into contact with the electrolytic solution by itself, or may be brought into contact with the electrolytic solution in the battery container together with the battery constituent material other than the negative electrode such as the positive electrode.

When the lithium negative electrode composite is brought into contact with the electrolytic solution by itself to perform the doping step, the handleability of the lithium negative electrode composite is improved as described above, and the assembly work of the lithium ion secondary battery becomes easy. Further, the negative electrode active material layer is porous having a large number of pores, and it is considered that an increase in density can be tolerated by the volume of the pores. Therefore, it is considered that the negative electrode active material layer doped with lithium in the doping step has a substantially smaller outer shape by the amount of the lost lithium layer, while the density increases. As a result, it is considered that the thickness of the lithium-doped negative electrode after the doping process is thinner than the thickness of the lithium negative electrode composite before the doping process.
Therefore, the amount of the lithium-doped negative electrode that can be put in the battery container of the same size is larger than the amount of the lithium negative electrode composite. In other words, the lithium-doped negative electrode can be filled in the battery container at a higher density than the lithium negative electrode composite. Therefore, in this case, it can be said that a lithium ion secondary battery having a large capacity can be manufactured.

On the other hand, when the lithium negative electrode composite is brought into contact with the electrolytic solution in the battery container together with the battery constituent material other than the negative electrode such as the positive electrode, the man-hours for manufacturing the lithium ion secondary battery are reduced. Further, as described above, the volume of the lithium-doped negative electrode after lithium doping is smaller than the volume of the lithium negative electrode composite before lithium doping. Therefore, when the lithium negative electrode composite is brought into contact with the electrolytic solution in the battery container to proceed with lithium doping, the difference between the volume of the lithium negative electrode composite before lithium doping and the lithium-doped negative electrode after lithium doping is the difference. There is a space in the battery container. Therefore, in this case, even when the negative electrode expands, it is difficult for a large stress to act on the battery components such as the negative electrode, and the lithium ion secondary battery that can withstand the expansion of the negative electrode due to charging and discharging for a long period of time, that is, has excellent durability. It can be said that a lithium ion secondary battery can be obtained.

By the way, the plate material remains on the surface of the lithium negative electrode composite after the pressing process. As described above, when this plate material is peeled off from the lithium negative electrode composite, stress acts on the lithium layer formed by rolling the lithium plate, and if the stress is excessive, the lithium layer may be damaged. There is sex.

However, if the lithium negative electrode complex is subjected to the doping step with the plate materials stacked, damage to the lithium layer and the like can be suppressed. That is, since the lithium in the lithium layer is transferred to the negative electrode active material layer by the doping step, the lithium layer disappears between the plate material and the negative electrode active material layer after the doping step. Therefore, the adhesion between the plate material and the negative electrode active material layer in this case is also low. Therefore, the plate material after the doping step is easily peeled off from the lithium negative electrode composite. Further, since the lithium layer is doped with the negative electrode active material layer and disappears, the lithium layer cannot be damaged.

The lithium ion secondary battery of the present invention having the lithium negative electrode composite of the present invention includes the lithium negative electrode composite or the lithium-doped negative electrode, a positive electrode body, an electrolytic solution and, if necessary, a separator. The positive electrode body has a current collector for the positive electrode and a positive electrode active material layer provided on the current collector for the positive electrode. The lithium negative electrode composite has a negative electrode current collector, a negative electrode active material layer provided on both sides of the negative electrode current collector, and a lithium layer provided on each negative electrode active material layer.

As the negative electrode active material, a negative electrode active material for a general lithium ion secondary battery can be used, for example, group 14 elements such as carbon, germanium and tin, group 13 elements such as aluminum and indium, zinc and cadmium. Group 12 elements such as antimony, group 15 elements such as bismuth, alkaline earth metals such as magnesium and calcium, and at least one simple substance, compound or alloy of group 11 elements such as silver and gold can be selected. Specific examples of the alloy or compound include tin-based materials such as Ag-Sn alloys, Cu-Sn alloys, and Co-Sn alloys, and carbon-based materials such as various graphites. Further, as the negative electrode active material, oxides such _{as Nb 2} O ₅ , TIO ₂ , Li ₄ Ti ₅ O ₁₂ , WO ₂ , MoO ₂ , Fe ₂ O _{3 or Li 3-x} M _x N (M = Co). , Ni, Cu) may be used.

Since the lithium negative electrode composite of the present invention is for doping the negative electrode active material layer with lithium, a Si-containing negative electrode active material having a large irreversible capacity can be preferably selected as the negative electrode active material.
Examples of the Si-containing negative electrode active material include elemental silicon, elemental silicon and _{silicon-based materials such as SiO x} (0.3 ≤ x ≤ 1.6) that disproportionate to silicon dioxide, elemental silicon or silicon-based materials, and carbon described later. Examples thereof include a composite in which system materials and the like are combined. Further, it is also preferable to use the silicon material disclosed in Patent Document 5 as the silicon-based material. Patent Document 5 discloses a silicon material having a structure in which a plurality of plate-shaped silicon bodies are laminated in the thickness direction. Then, in Patent Document 5, _{a layered silicon compound containing polysilane as a main component, which is obtained by reacting CaSi 2} with an acid to remove Ca, is synthesized, and the layered silicon compound is heated at 300 ° C. or higher to release hydrogen. It describes the manufacture of the silicon material and the lithium ion secondary battery containing the silicon material as an active material.

The negative electrode active material layer may contain, if necessary, an additive such as a conductive auxiliary agent, a binder, and a dispersant in an appropriate amount in addition to the negative electrode active material. Similarly, since the positive electrode active material layer can also contain these additives in an appropriate amount in addition to the positive electrode active material described later, the following sections include the negative electrode active material layer and the positive electrode active material layer. I will explain. Hereinafter, if necessary, the negative electrode and the positive electrode are collectively referred to as an electrode, the negative electrode active material and the positive electrode active material are collectively referred to as an active material, and the negative electrode active material layer and the positive electrode active material layer are collectively referred to as an active material layer. That is.

Conductive aids are added to increase the conductivity of the electrodes. The conductive auxiliary agent may be a chemically inert electron high conductor, and examples thereof include carbon black, which are carbonaceous fine particles, graphite, Vapor Grown Carbon Fiber, and various metal particles. .. Examples of carbon black include acetylene black, Ketjen black (registered trademark), furnace black, and channel black. These conductive auxiliary agents can be added to the active material layer alone or in combination of two or more.

The binder plays a role of binding the active material or the like to the surface of the current collector. Examples of the binder include fluororesins such as polyvinylidene fluoride, polytetrafluoroethylene and fluororubber, thermoplastic resins such as polypropylene and polyethylene, imide-based resins such as polyimide and polyamideimide, and alkoxysilyl group-containing resins. be able to. Further, a polymer having a hydrophilic group may be adopted as the binder. Examples of the hydrophilic group of the polymer having a hydrophilic group include a carboxyl group, a sulfo group, a silanol group, an amino group, a hydroxyl group and a phosphoric acid group. Specific examples of the polymer having a hydrophilic group include polyacrylic acid, carboxymethyl cellulose, polymethacrylic acid, and poly (p-styrene sulfonic acid).
Known additives such as dispersants other than the conductive auxiliary agent and the binder can be adopted.

A current collector is a chemically inert electronic high conductor that keeps current flowing through the electrodes during the discharge or charging of a lithium ion secondary battery. As a current collector, at least one selected from silver, copper, gold, aluminum, magnesium, tungsten, cobalt, zinc, nickel, iron, platinum, tin, indium, titanium, ruthenium, tantalum, chromium, molybdenum, and stainless steel. Metallic materials such as can be exemplified.

The current collector may be covered with a known protective layer. A current collector whose surface is treated by a known method may be used as the current collector.
Further, the current collector can take the form of a foil, a sheet, a film, a linear shape, a rod shape, a mesh or the like. Therefore, as the current collector, for example, a metal foil such as a copper foil, a nickel foil, an aluminum foil, or a stainless steel foil can be preferably used.

To form an active material layer on the surface of the current collector, a conventionally known method such as a roll coating method, a die coating method, a dip coating method, a doctor blade method, a spray coating method, or a curtain coating method is used to collect electricity. An electrode mixture having an active material may be applied to the surface of the body. Specifically, an active material, a solvent, and if necessary, a binder and a conductive auxiliary agent are mixed to form a slurry-like electrode mixture, and the slurry-like electrode mixture is applied to the surface of the current collector. ,dry. Examples of the solvent include N-methyl-2-pyrrolidone, methanol, methyl isobutyl ketone, and water. In order to increase the electrode density, the dried one may be compressed.
When the lithium ion secondary battery of the present invention has a plurality of negative electrodes, at least one negative electrode may be the lithium negative electrode composite or the lithium-doped negative electrode of the present invention. That is, the lithium ion secondary battery of the present invention may have a negative electrode other than the lithium negative electrode composite or the lithium-doped negative electrode of the present invention. The negative electrode may have a negative electrode active material layer on only one side of the current collector, or may not be lithium-doped.

The positive electrode active material used for the positive electrode is not particularly limited, and a general positive electrode active material for a lithium ion secondary battery can be used.
Common cathode active material for lithium ion secondary batteries, the general formula of the layered rock salt _{structure: Li a Ni b Co c Mn} d D e O f (0.2 ≦ a ≦ 2, b + c + d + e = 1,0 ≦ e <1, D are W, Mo, Re, Pd, Ba, Cr, B, Sb, Sr, Pb, Ga, Al, Nb, Mg, Ta, Ti, La, Zr, Cu, Ca, Ir, Hf, It is represented by at least one element selected from Rh, Fe, Ge, Zn, Ru, Sc, Sn, In, Y, Bi, S, Si, Na, K, P and V, 1.7 ≦ f ≦ 3). Lithium composite metal oxide, Li ₂ MnO ₃ can be mentioned. Further, as the positive electrode active material, _{a metal oxide having a spinel structure such as LiMn 2} O ₄ , a solid solution composed of a mixture of the metal oxide having a spinel structure and a layered compound, LiMPO ₄ , LiMVO ₄ or Li ₂ MSiO ₄ (in the formula). M is selected from at least one of Co, Ni, Mn, and Fe) and the like. Furthermore, as the positive electrode active material, tavorite compound (the M a transition metal) LiMPO ₄ F, such as LiFePO ₄ F represented by, Limbo ₃ such LiFeBO ₃ (M is a transition metal) include borate-based compound represented by be able to. Any metal oxide used as the positive electrode active material may have the above composition formula as the basic composition, and those in which the metal element contained in the basic composition is replaced with another metal element can also be used.

The above-mentioned lithium negative electrode composite or lithium-doped negative electrode of the present invention may be placed in a battery container together with a positive electrode and, if necessary, a known separator, and an electrolytic solution may be injected to obtain a lithium ion secondary battery.

The electrolytic solution contains an organic solvent and a lithium salt dissolved in the organic solvent.
As the organic solvent, cyclic esters, chain esters, ethers and the like can be used. Examples of the cyclic esters include ethylene carbonate, propylene carbonate, butylene carbonate, gamma-butyrolactone, vinylene carbonate, 2-methyl-gamma-butyrolactone, acetyl-gamma-butyrolactone, and gamma-valerolactone. Examples of the chain esters include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dipropyl carbonate, ethylmethyl carbonate, propionic acid alkyl ester, malonic acid dialkyl ester, acetic acid alkyl ester and the like. Examples of ethers include tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane and 1,2-dibutoxyethane. These organic solvents may be used alone or in combination of two or more as the electrolytic solution.

Examples of the lithium salt include LiClO ₄ , LiAsF ₆ , LiPF _{6 , LiBF 4} , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (FSO ₂ ) _{2, and the} like.

_{As the electrolytic solution, lithium salts such as LiClO 4} , LiPF ₆ , LiBF ₄ , and LiCF ₃ SO ₃ are added to an organic solvent such as ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate, propylene carbonate, and dimethyl carbonate from 0.5 mol / l. An example is an example of a solution dissolved at a concentration of about 1.7 mol / l.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. As long as it does not deviate from the gist of the present invention, it can be carried out in various forms with modifications, improvements, etc. that can be made by those skilled in the art. In addition, each component shown in the present specification including the embodiment and the following examples can be arbitrarily extracted and combined.

Hereinafter, the present invention will be described in more detail with reference to test examples and examples. The present invention is not limited to these examples.

(Test Example 1)
The following tests were conducted to clarify the optimum magnitude of the surface pressure applied to the laminate from the press machine.
First, the same laminated body as the laminated body used in Example 1 described later was prepared. The laminate is formed on a negative electrode having negative electrode active material layers formed on two surfaces of a current collector for negative electrodes, a lithium plate laminated on each of the two negative electrode active material layers, and two lithium plates, respectively. It is composed of a peeled layer and a plate material laminated on each of the two peeled layers. It can also be said that the laminated body has a lithium plate arranged on the negative electrode active material layer of the negative electrode.

Three of the same laminates were prepared, and the laminates were pressed using a roll press machine. The thickness of the laminated body is about 120 μm, and the roll press machine for pressing the laminated body is set so that the distance between the two rolls is 70 μm, 100 μm, or 140 μm. The laminate A is roll-pressed at a distance of 70 μm between rolls, the laminate B is roll-pressed at a distance of 100 μm between rolls, and the laminate C is roll-pressed at a distance of 140 μm between rolls. did. For the laminated body A to the laminated body C, the plate material was peeled off immediately after pressing, and the DC resistance of each was measured. Moreover, the plate material was peeled off immediately after pressing the laminated body A to the laminated body C and left at room temperature, and the change in appearance was observed with time. The time when no metallic luster was visually confirmed on the surface of the laminated body was determined to be the time when the doping was completed.
The results are shown in Table 1.

As shown in Table 1, the DC resistance of the laminate A immediately after production was 9.4 mΩ, and the DC resistance of the laminate B immediately after production was as low as 8.8 mΩ, whereas the DC resistance of the laminate C immediately after production was as low as 8.8 mΩ. The DC resistance of was 88 mΩ, which was a very high value. Regarding the laminated body C, since the distance of 140 μm between the two rolls at the time of roll pressing is slightly larger than the thickness of the laminated body of 120 μm, it is considered that the lithium plate was not sufficiently pressure-bonded to the negative electrode. Since the lithium plate is not sufficiently crimped to the negative electrode, it is considered that a gap is formed between the two, which becomes a resistance component and the DC resistance value becomes a large value. Further, in the laminated body C, since the lithium plate is not sufficiently pressure-bonded to the negative electrode, the lithium doping by the direct doping method does not proceed sufficiently, and even if 24 hours have passed after the start of the doping, the lithium It is probable that the dope was not completed.
From this result, it can be seen that if the DC resistance of the laminated body after pressing, that is, the lithium negative electrode complex is 88 mΩ or more, it is difficult to say that the lithium negative electrode complex is suitable for the direct doping method. Further, based on the above results, a lithium negative electrode complex having a DC resistance of 10 mΩ or less is considered to be particularly suitable for the direct doping method.

(Test Example 2)
By the press machine used in Example 1 described later, the same laminate as that used in Test Example 1 above was obtained at 0.5 kN / cm ² , 1.0 kN / cm ² , 1.5 kN / cm ² , and 5.00 kN. Pressed at each surface pressure of / cm ^2. The plate material was peeled off from each lithium negative electrode composite obtained by the press, and the DC resistance of each lithium negative electrode complex immediately after production was measured. Further, the same laminate was pressed three times at a surface pressure of 1.25 kN / cm ² , and the DC resistance of the lithium negative electrode complex was measured in the same manner. The results are shown in Table 2.

As shown in Table 2, when the laminate ^{was pressed at a surface pressure of 1.5 kN / cm 2} or less, the DC resistance of each of the obtained lithium negative electrode complexes exceeded 10 mΩ. Even with a small surface pressure of about 1.25 kN / cm ^2, a lithium negative electrode complex with a DC resistance of 10 mΩ or less can be obtained by pressing multiple times, but in this case, the manufacturing man-hours are excessive and the lithium negative electrode is used. There is a problem that it is difficult to efficiently manufacture the complex.
On the other hand, when the laminated body was ^{pressed at a surface pressure of 5.0 kN / cm 2} , a lithium negative electrode composite having a DC resistance of 10 mΩ or less was obtained by one press. Considering the results shown in Table 2, the relationship between the DC resistance of the lithium negative electrode composite and the surface pressure during pressing is linear in the range of ^{surface pressure 0.5 to 1.5 kN / cm 2, and the surface pressure is 2.6 kN.} It is considered that the linear relationship ends at / cm ² and the DC resistance remains constant even if the surface pressure increases further. From this, it is presumed that if the surface pressure at the time of pressing is 2.6 kN / cm ² or more, a lithium negative electrode composite having a DC resistance of 10 mΩ or less can be obtained by one press. Further, it can be seen that in order to more reliably obtain a lithium negative electrode complex having a DC resistance of 10 mΩ or less in one press, ^{it is preferable to set the surface pressure at the time of pressing to 5.0 kN / cm 2 or more.} In the following examples, the surface pressure during pressing was set to 20 kN / cm ² .

(Example 1)
(Manufacturing of lithium negative electrode complex)
FIG. 1 shows an explanatory diagram schematically showing a method for manufacturing the lithium negative electrode complex of Example 1 using the apparatus for manufacturing the lithium negative electrode complex of Example 1, and FIG. 2 is an enlarged view of a main part of the X portion in FIG. Shown in. FIG. 3 shows an explanatory diagram schematically showing the lithium negative electrode complex of Example 1 obtained by the method for producing the lithium negative electrode complex of Example 1. Hereinafter, the terms "upper" and "lower" refer to the upper and lower parts shown in FIG.

The press device 1 shown in FIG. 1 is an example of a press device capable of producing the lithium negative electrode composite of Example 1. As shown in FIG. 1, the press device 1 includes a frame 2, a press unit 3, and a drive unit 4.

The frame 2 has a lower table 21 and an upper table 22 facing each other vertically apart from each other, and a support portion 23 connecting the lower table 21 and the upper table 22. The lower table 21 has a substantially flat plate shape, and the upper table 22 has a through hole 22o.

The drive unit 4 has a drive device 41 and a rod 42. The drive device 41 is integrated with the frame 2. The rod 42 has an elongated columnar shape and is inserted through the through hole 22o. One end of the rod 42 is held by the drive device 41. The other end of the rod 42 holds the first press mold 31, which will be described later, between the upper table 22 and the lower table 21. In Example 1, a hydraulic cylinder device was used as the drive device 41. The drive device 41 may reciprocate the rod 42 up and down.

The press unit 3 is composed of a first press mold 31 and a second press mold 32. The first press mold 31 and the second press mold 32 have a substantially flat plate shape and are arranged so as to face each other vertically. The first press mold 31 is held by the rod 42 with the first press surface 31p facing downward. The second press mold 32 is held on the lower table 21 with the second press surface 32p facing upward. When the rod 42 is reciprocated up and down by the drive device 41, the first press mold 31 held by the rod 42 also reciprocates up and down. When the first press mold 31 moves downward, the first press surface 31p of the first press mold 31 and the second press surface 32p of the second press mold 32 come close to each other. When the first press die 31 moves upward, the first press surface 31p of the first press die 31 and the second press surface 32p of the second press die 32 are separated from each other. In the press device 1, it can be said that the first press die 31 is a movable type and the second press die 32 is a fixed type.

The method for producing the lithium negative electrode complex of Example 1 will be described below.

The method for producing a lithium negative electrode composite of Example 1 includes a negative electrode forming step, a lithium plate material composite forming step, and a pressing step.

<Negative electrode forming process>
<Manufacturing of silicon material>
_{Prepare concentrated hydrochloric acid containing 1% by mass of hydrogen fluoride, add 5 g of CaSi 2} to 20 ml of the concentrated hydrochloric acid in an ice bath at 0 ° C., stir for 1 hour, then add water and stir for another 5 minutes. The reaction solution was obtained. The yellow solid content obtained by filtering the reaction solution was washed with water and ethanol, and dried under reduced pressure to obtain layered polysilane. This layered polysilane was heated at 500 ° C. under an argon atmosphere to obtain a silicon material in which hydrogen was removed from the polysilane.
Using the silicon material as a Si-containing negative electrode active material, the negative electrode 90 was manufactured by the following method.

<Manufacturing of negative electrode>
70 parts by mass of the above silicon material as the Si-containing negative electrode active material, 15 parts by mass of natural graphite as the other negative electrode active material, 5 parts by mass of acetylene black as the conductive auxiliary agent, and 15 parts by mass of the polyamide-imide as the binder. At the same time, an appropriate amount of N-methyl-2-pyrrolidone was added to this mixture to obtain a slurry-like negative electrode mixture. A 25 μm electrolytic copper foil is prepared as the negative electrode current collector 91, and a negative electrode mixture is applied to both sides of the negative electrode current collector 91 using a doctor blade, and the negative electrode mixture is used as the negative electrode mixture. A negative electrode precursor having a layer and a current collector 91 for a negative electrode was obtained. The negative electrode precursor was dried to volatilize N-methyl-2-pyrrolidone in the negative electrode mixture. The dried negative electrode precursor was rolled by a roll press device (not shown) so that the thickness of the negative electrode mixture layer was 70 μm. By this rolling, the negative electrode mixture layer and the negative electrode current collector 91 were firmly integrated. The density of the negative electrode mixture layer at this time was 1.2 g / cm ³ .

The rolled negative electrode precursor is further heated at 200 ° C. for 2 hours under reduced pressure to form a first negative electrode active material layer formed on one surface of the negative electrode current collector 91 and the negative electrode current collector 91. A negative electrode 90 having a 92 and a second negative electrode active material layer 93 formed on the other surface of the negative electrode current collector 91 was obtained (see FIG. 2). In the negative electrode 90, the thickness of the first negative electrode active material layer 92 and the second negative electrode active material layer 93 was about 63 to 100 μm, respectively. The thickness of the current collector 91 for the negative electrode was about 25 μm. The negative electrode 90 cut into a predetermined shape was used in a pressing process described later.

(Lithium plate composite formation process)
In the production method of Example 1, a film manufactured by Lintec Corporation and having a thickness of about 25 μm was used as a composite of the plate material 60 and the release layer 61. The plate material 60 is a resin film made of polyethylene terephthalate, and the release layer 61 is a silicone layer. The release layer 61 is formed on the plate material 60. The raw material of the release layer 61 is KS-847H (manufactured by Shin-Etsu Chemical Co., Ltd.), which is an addition-curable silicone adhesive, in an amount of 30 parts by mass in terms of solid content, and SD4584 (Toray Industries, Inc.), which is also an addition-curable silicone adhesive. 18 parts by mass of Doukoning Co., Ltd. in terms of solid content, 1.6 parts by mass of PL-50T (manufactured by Shin-Etsu Chemical Co., Ltd.), which is a platinum catalyst, and toluene as a solvent are added to the solid content. The concentration is about 30% by mass. The peeling layer 61 was formed by applying the raw material of the peeling layer 61 on the above-mentioned plate material 60, heating at 130 ° C. for 2 minutes to cure, and volatilizing the solvent. The thickness of the release layer 61 is 0.05 μm, and the thickness of the plate 60 is 25 μm. Further, a lithium plate 62 having a thickness of 100 μm was superposed on the release layer 61 to obtain a lithium plate material complex 6 (see FIG. 2). The lithium plate composite 6 cut into a predetermined shape was used in the following pressing process.

(Press process)
As shown in FIGS. 1 and 2, a negative electrode 90 and a lithium plate material composite 6 were used in the pressing process.
A lithium plate composite 6 was laminated on each of the first negative electrode active material layer 92 and the second negative electrode active material layer 93 of the negative electrode 90 to obtain a laminate 95 in which the negative electrode 90 was sandwiched between the two lithium plate composites 6. In the laminated body 95, the lithium plate 62 of each lithium plate material complex 6 was arranged on the negative electrode 90, respectively.

The drive device 41 was operated to separate the first press mold 31 and the second press mold 32, and the above-mentioned laminated body 95 was arranged between the first press surface 31p and the second press surface 32p. Then, by operating the drive device 41 and bringing the first press die 31 and the second press die 32 close to each other, the laminated body 95 was pressed in the thickness direction thereof. At this time, the surface pressure of the first press surface 31p and the second press surface 32p acted on the laminated body 95, and the first negative electrode active material layer 92 and the second negative electrode active material layer 93 were in close contact with the lithium plate 62, respectively. At this time, the pressing pressure acting on the laminated body 95 by the pressing device 1 was a surface pressure of 20 kN / cm ² , and the thickness of the lithium plate 62 after pressing was 25 μm. That is, in the pressing process, the lithium plate 62 was compressed, stretched and deformed until the compression ratio reached 75%. For reference, the thickness of the negative electrode current collector 91 after pressing was 25 μm, which was the same as before pressing. The thickness of the first negative electrode active material layer 92 and the second negative electrode active material layer 93 after pressing was about 63 to 100 μm, which was the same as before pressing.

After performing the above press, the drive device 41 was operated, and the first press die 31 and the second press die 32 were separated again. Then, the laminated body 95 after pressing, that is, the lithium negative electrode composite 96 of Example 1, was taken out from between the first press surface 31p and the second press surface 32p. Through the above steps, the lithium negative electrode complex 96 of Example 1 was obtained.

(Example 2)
A complex having a diamond-like carbon layer formed on the surface of the plate was prepared. The diamond-like carbon layer in this complex was used as a release layer. In the same manner as in Example 1, a lithium plate was laminated on the peeling layer to form a lithium plate composite, and the lithium plate composite was laminated on the negative electrode active material layer of the negative electrode to obtain a laminated body having a thickness of 120 μm. The same pressing process as in Example 1 was performed on the laminate to produce the lithium negative electrode composite of Example 2.

(Comparative Example 1)
Using a roll press machine, the same laminate as that used in Example 1 was roll-pressed with a load having a linear pressure of 20 kN / cm to produce a lithium negative electrode complex of Comparative Example 1.

(Evaluation Appearance evaluation)
The plate material 60 was peeled off from the two surfaces of the lithium negative electrode composite 96 (see FIG. 3) of Example 1 immediately after production. The lithium negative electrode composite 96 of Example 1 after the plate material 60 was peeled off was visually inspected, and the first negative electrode active material layer 92, the lithium layer 62 on the first negative electrode active material layer 92, the second negative electrode active material layer 93, And whether or not the lithium layer 62 on the second negative electrode active material layer 93 was damaged was evaluated.
Similarly, the appearance of the lithium negative electrode complex of Example 2 and the lithium negative electrode complex of Comparative Example 1 was visually evaluated.

The above-mentioned damage was not observed in the lithium negative electrode complex of Example 1 and the lithium negative electrode complex of Example 2. On the other hand, in the lithium negative electrode complex of Comparative Example 1, many large breaks occurred in the negative electrode active material layers 92 and 93.
From this result, according to the manufacturing methods of Examples 1 and 2 in which the surface pressure was applied to the laminated body, unlike the manufacturing method of Comparative Example 1 in which the linear pressure was applied to the laminated body, the negative electrode active material layer was used. It can be said that a damage-free lithium negative electrode composite can be manufactured.
Further, from this result, the lithium layer and the negative electrode active material layer were damaged by either the manufacturing method of Example 1 using the silicone-based stripping agent and the manufacturing method of Example 2 using the carbon-based stripping agent. It can be said that a non-lithium negative electrode composite can be obtained.

Similar appearance evaluations were also performed on various lithium negative electrode complexes obtained by pressing the laminates with surface pressures of various sizes.
Specifically, a plurality of laminates using the same silicone-based release agent as in Example 1 and a plurality of laminates using the same carbon-based release agent as in Example 2 are prepared, and each laminate is prepared from 1 to 1. Pressed at various surface pressures in the range of 30 kN / cm ^2. When the appearance evaluation of each of the obtained lithium negative electrode complexes was carried out in the same manner as described above, no damage was observed in the lithium layer and the negative electrode active material layer in any case. From this result, it can be said that a lithium negative electrode complex in which the lithium layer and the negative electrode active material layer are not damaged can be produced by setting the surface pressure at the time of pressing to 30 kN / cm ^{2 or less.}

(Test Example 3)
A lithium negative electrode complex was obtained by roll-pressing the laminate with a roll press machine according to the manufacturing method of Comparative Example 1 under the condition that the negative electrode active material layer was not damaged. When the lithium negative electrode complex is brought into contact with the electrolytic solution, when it is left as it is without being brought into contact with the electrolytic solution, and when it is brought into contact with an organic solvent containing no electrolyte, the lithium-doped compound is used. The degree was evaluated. _{As the electrolytic solution, one in which LiPF 6} was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1 was used. The organic solvent used for this electrolytic solution was used as the organic solvent.
The lithium negative electrode composite left as it was without contacting the electrolytic solution was designated as Test Example 3-1 and the lithium negative electrode composite contacted with the electrolytic solution was designated as Test Example 3-2, and the lithium negative electrode composite contacted with the organic solvent was designated. As Test Example 3-3, the change over time in the thickness of the lithium layer was measured for each lithium negative electrode composite. Since the lithium negative electrode complex after the test is lithium-doped, it can be said to be a lithium-doped negative electrode.
The results of Test Example 3-1 and Test Example 3-2 are shown in Table 3.

As shown in Table 3, in the lithium negative electrode complex of Test Example 3-1 left without contact with the electrolytic solution, the rate of decrease of the lithium layer was very slow, and the lithium layer gradually disappeared 48 hours after the start of the test. .. On the other hand, in the lithium negative electrode complex of Test Example 3-2 in contact with the electrolytic solution, the rate of decrease of the lithium layer was very fast, and the lithium layer disappeared 3 hours after the start of the test. Since the lost lithium layer is considered to have been doped into the negative electrode active material layer, it can be said from this result that the lithium doping proceeds rapidly in the presence of the electrolytic solution. Further, it can be said that lithium doping proceeds even in the absence of the electrolytic solution, albeit very slowly.

On the other hand, in the lithium negative electrode complex of Test Example 3-3, the lithium layer was gradually formed 48 hours after the start of the test, as in the case of the lithium negative electrode complex of Test Example 3-1 which was left uncontacted with the electrolytic solution. Disappeared. This result suggests that lithium doping proceeds via lithium ions in the electrolytic solution.

1: Press device 2: Frame 21: Lower table 22: Upper table 23: Support portion 22o: Through hole 3: Press portion 31: First press mold 32: Second press mold 31p: First press surface 32p: Second Press surface 4: Drive unit 41: Drive device 42: Rod 6: Lithium plate composite 60: Plate 61: Peeling layer 62: Lithium plate 90: Negative electrode 91: Current collector for negative electrode 92: First negative electrode active material layer 93: Second negative electrode active material layer 95: laminated body 96: lithium negative electrode composite

Claims (7)

A method for producing a lithium negative electrode composite having a negative electrode having a negative electrode active material layer formed on the surface of the current collector and the current collector, and a lithium layer formed on the negative electrode active material layer. There,
It has a pressing process in which a surface pressure is applied to a laminate in which a lithium plate is arranged on the negative electrode in a direction in which the negative electrode and the lithium plate are in close contact with each other by using a press machine.
Or the thickness of the lithium plate is 25μm or more, and / or, in the pressing step, the load acting on the laminate per unit area is at 5 kN / cm ² or more 30 kN / cm ² or less,
A method for producing a lithium negative electrode composite, in which a plate material is interposed between the press machine and the lithium plate and a release agent is interposed between the lithium plate and the plate material in the pressing step. The method for producing a lithium negative electrode composite according to claim 1, wherein the release agent is at least one selected from a silicone-based release agent, an inorganic powder-based release agent, and a carbon-based release agent. A doping step of contacting the lithium negative electrode composite obtained by the method for producing a lithium negative electrode composite according to claim 1 or 2 with an electrolytic solution containing an organic solvent and a lithium salt to obtain a lithium-doped negative electrode. A method for manufacturing a lithium-doped negative electrode. A method for producing a lithium negative electrode composite having a negative electrode having a negative electrode active material layer formed on the surface of the current collector and the current collector, and a lithium layer formed on the negative electrode active material layer. There,
It has a pressing process in which a surface pressure is applied to a laminate in which a lithium plate is arranged on the negative electrode in a direction in which the negative electrode and the lithium plate are in close contact with each other by using a press machine.
The above obtained by the method for producing a lithium negative electrode composite, in which a plate material is interposed between the press machine and the lithium plate and a release agent is interposed between the lithium plate and the plate material in the pressing step. A method for manufacturing a lithium-doped negative electrode, comprising a doping step of contacting a lithium negative electrode composite with an electrolytic solution containing an organic solvent and a lithium salt while the plate materials are stacked to obtain a lithium-doped negative electrode. The lithium negative electrode composite obtained by the method for producing a lithium negative electrode composite according to claim 1 or 2, is brought into contact with an electrolytic solution containing an organic solvent and a lithium salt while the plate materials are stacked to be lithium-doped. A method for manufacturing a lithium-doped negative electrode, which comprises a doping step for obtaining a negative electrode. An electrolytic solution in a battery container containing the lithium negative electrode composite obtained by the method for producing a lithium negative electrode composite according to claim 1 or 2, and a positive electrode body having a current collector and a positive electrode active material layer. A method for manufacturing a lithium-ion secondary battery. In a battery container containing the lithium-doped negative electrode obtained by the method for producing a lithium-doped negative electrode according to any one of claims 3 to 5, and a positive electrode body having a current collector and a positive electrode active material layer. A method for manufacturing a lithium ion secondary battery in which an electrolytic solution is injected.

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