JP6540130B2 - Electrode material for battery and all solid lithium ion battery - Google Patents

Description

  The present invention relates to a battery electrode material and an all solid lithium ion battery provided with the battery electrode material. More specifically, a battery electrode material which is an ultra thin film, can be enlarged, can be used in a flexible form, and has high safety, and an all solid lithium ion battery including the battery electrode material About.

  In recent years, the demand for energy saving has been particularly increasing, and technology relating to storage has also become important. Lithium-ion batteries, sodium-sulfur batteries, nickel-metal hydride batteries, etc. are known as batteries used for storage, among which lithium-ion batteries have high energy density and low cost per unit capacity. It is used in various applications such as automotive applications and power supplies for mobile phones.

  Lithium ion batteries are considered to be used for various applications in addition to the above applications, and are expected to be used for wearable device applications represented by smart watches and smart glasses, for example. In addition, it is expected that performance and physical properties that can not be achieved by current lithium ion batteries are required in the future, and in particular, it is an ultra thin film, can be enlarged, can be used in a flexible form, It has been awaited the appearance of a storage element having a feature of high safety.

  As a conventional lithium ion battery, for example, an electrolyte-based lithium ion battery composed of a positive electrode, a negative electrode, a separator, and a non-aqueous electrolytic solution containing a lithium salt is known (see, for example, Patent Document 1).

  Moreover, as another form of the conventional lithium ion battery, an all solid lithium ion battery constituted by a positive electrode, a negative electrode, and a solid electrolyte formed by sputtering lithium phosphate oxynitride glass electrolyte etc. on the positive electrode Are known (see, for example, Patent Document 2).

  However, in the electrolyte type lithium ion battery, since it is necessary to seal so that the electrolyte does not leak, a certain thickness for the sealing member is required, and it is difficult to form an ultra thin film. Moreover, since it is necessary to set it as the form which electrolyte solution does not leak, it is difficult from a viewpoint of safety | security to set it as a flexible form.

  Further, in the all solid lithium ion battery in which the solid electrolyte is formed by sputtering, it is technically difficult to perform sputtering in a wide range, so it is difficult to increase the area. Moreover, since it is solid, it is difficult to make it flexible, and its application is limited, and it can not cope with various usage forms.

Patent No. 4407205 gazette JP, 2014-49205, A

  The present invention has been made in view of the above problems and circumstances, and the problem to be solved is an ultra thin film, which can be enlarged in area, can be used in a flexible form, and has high safety. It is providing an electrode material. Another object of the present invention is to provide an all solid lithium ion battery including the battery electrode material.

The inventor of the present invention has made a monomolecular film capable of delivering lithium ions on a conductive substrate (current collector) in which at least a part of the substrate surface has been oxidized in the process of studying to solve the above problems. By forming a layer and forming a solid electrolyte and a negative electrode thereon, it has been found that a lithium ion battery which can be made thin and large in area can be produced, and the present invention has been made.
That is, the above-mentioned subject concerning the present invention is solved by the following means.

1. Some metal oxide on the substrate surface including the conductive substrate at least the surface of the substrate, is a monomolecular film formed by using a compound having a structure represented by the following general formula (1) An electrode material for a battery characterized by
General formula (1) R ₁ S-L-R ₂
(Wherein, R ₁ represents a hydrogen atom, a lithium atom or a sodium atom. Moreover, the sulfur atoms of the compounds having the structures represented by two general formulas (1), where R ₁ is a single bond, optionally a compound connected with -S bond (disulfide bond) .L is a thienyl group represents including linking group, R ₂ represents a mosquito Rubokishi group.)

2 . The monolayer cell electrode material according to paragraph 1, which is a self-assembled monolayer.

3 . _{3. The} electrode material for a battery according to claim 1 or 2 , wherein the substrate surface contains aluminum oxide (Al ₂ O ₃ ) or indium tin oxide (ITO).

4 . The arithmetic mean roughness Ra of the substrate surface on which the monomolecular film is formed in the conductive substrate is 5 nm or more, according to any one of the items 1 to 3 , Battery electrode material.

5 . An all-solid lithium ion battery comprising the battery electrode material according to any one of items 1 to 4 .

By forming the monomolecular film layer on the surface of the substrate of the ultrathin film by the above means of the present invention, it is possible to provide an electrode material for a battery of ultrathin film. In addition, since the battery electrode material of the present invention only needs to form a monomolecular film on the surface of the substrate, it can be produced on substrates of all forms such as ultra thin films and flexible substrates, and has a large area. It is possible to provide a highly safe battery electrode material that can be configured in a flexible form and can be used.
Moreover, the all-solid-state lithium ion battery containing the said electrode material for batteries can be provided.

The mechanism for expressing the effect of the present invention or the mechanism of action is not clear but is presumed as follows.
A monomolecular film is densely formed on the surface of the conductive substrate (current collector) of the present invention using a compound having a structure represented by the general formula (1). Here, since a large number of sulfur atoms (positive electrode active material) are exposed on the surface of the monomolecular film, lithium ions can be efficiently delivered on the surface of the monomolecular film, and as an electrode material Is presumed to have the function of

Schematic diagram of all solid lithium ion battery A schematic diagram illustrating the structure of a monolayer

Cell electrode materials of the present invention, at least a portion of the substrate surface on the substrate surface of the conductive substrate comprising a metal oxide, a compound having a structure represented by the before following general formula (1) It is characterized in that a monomolecular film is formed by using it. This feature is a technical feature common to the following embodiments.

As an embodiment of the present invention, from the viewpoint of exhibiting the effects of the present invention, in the general formula (1), L represents a linking group containing a thienyl group, and R ₂ is required to be a carboxy group. Since the thienyl group has high conductivity and can retain Li in the molecule, it is possible to improve the speed of charge and discharge and to improve the discharge capacity. Since the carboxy group has a large interaction with the oxidized conductive substrate portion, the formation efficiency of the monomolecular film can be improved.

Furthermore, in the present invention, the substrate surface preferably contains aluminum oxide (Al ₂ O ₃ ) or indium tin oxide (ITO) from the viewpoint of the formation efficiency of a monomolecular film.

  Further, in the present invention, the monomolecular film is preferably a self-assembled monomolecular film. As a result, the monomolecular film of the present invention can be formed at a high density on the surface of the base material, and more lithium ions can be delivered, so that the discharge capacity can be improved.

  Moreover, in the present invention, it is preferable that arithmetic mean roughness Ra of the base-material surface in which the said monomolecular film is formed is 5 nm or more. By forming fine irregularities on the surface of the substrate such that the arithmetic average roughness Ra is 5 nm or more, the surface area of the surface of the substrate becomes large, so many molecules to which lithium ions can be transferred are bonded to the surface of the substrate And the discharge capacity can be improved. Moreover, when there are many micro unevenness | corrugations on the base-material surface, it is preferable at the point which can improve the adhesiveness of the base-material surface and the electrode material for batteries of this invention by the anchor effect.

  The battery electrode material of the present invention can be suitably included in an all solid lithium ion battery. As a result, it is possible to manufacture an all-solid-state lithium ion battery which is an ultra-thin film, can be enlarged in area, can be used in a flexible form, and has high safety.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In the present application, “to” is used in the meaning including the numerical values described before and after that as the lower limit value and the upper limit value.

[Electrode material for battery and all solid lithium ion battery]
The battery electrode material of the present invention comprises a compound having a structure represented by the general formula (1) on the substrate surface of the positive electrode current collector 10 in which at least a part of the substrate surface contains a metal oxide. It is characterized in that a monomolecular film layer 20 is formed.
In addition, the battery electrode material of the present invention can be suitably used as a positive electrode of the all solid lithium ion battery 1. For example, the all solid lithium ion battery 1 can be configured by sequentially laminating the electrolyte layer 30, the negative electrode 40, the negative electrode current collector 50, and the like on the battery electrode material (FIG. 1).

(1) Positive electrode current collector 10
The positive electrode current collector 10 is a conductive base material having conductivity, and for example, Cu, Al, indium tin oxide (ITO), a glass base material, or the like can be used. In addition, in order to form the monomolecular film layer 20 on the surface of the positive electrode current collector 10, a material having a low interaction with R ₁ S in General Formula (1) described later and a large interaction with R ₂ is used. Is preferred. Specifically, for example, the substrate surface of the positive electrode current collector 10 preferably includes a metal oxide such as aluminum oxide (Al ₂ O ₃ ) or indium tin oxide (ITO).

  In addition, it is preferable that the positive electrode current collector 10 performs oxygen plasma treatment, UV ozone treatment, or the like on the surface of the substrate so that reactive groups such as OH groups exist on the surface of the substrate.

In addition, the positive electrode current collector 10 is subjected to surface treatment by wet etching with a solvent, dry etching by plasma etching, ion etching or the like as a roughening treatment of the substrate surface, and minute unevenness is formed on the substrate surface. It is preferable to keep it in the formed state.
Specifically, from the viewpoint of forming a monomolecular film with a large number of single molecules, it is preferable to carry out surface treatment so that the arithmetic mean roughness Ra of the substrate surface is 5 nm or more. By forming a large number of minute irregularities on the surface of the substrate, the surface area of the surface of the substrate is increased, so that a large number of transferable molecules of lithium ions can be bonded to the surface of the substrate, and the discharge capacity is improved. Can. Moreover, when there are many fine unevenness on the substrate surface, it is preferable in that the adhesion between the substrate surface and the battery electrode material of the present invention can be enhanced by the anchor effect, and the utilization factor of the positive electrode active material Discharge capacity can be improved.
Here, the arithmetic average roughness Ra is a value determined according to a surface roughness standard (JIS B 0601-2001) from measurement by an atomic force microscope (AFM).

(2) Monolayer 20
The monomolecular film layer 20 is a layer formed by bonding a large number of compounds having a structure represented by the following general formula (1) on the substrate surface of the positive electrode current collector 10, It is preferable that it is formed of an organic monolayer (SAM).
General formula (1) R ₁ S-L-R ₂

The compound having a structure represented by the general formula (1) interacts with a reactive group such as an OH group present on the substrate surface of the positive electrode current collector 10 by R ₂ to have a physical action (for example, The van der Waals interaction) or reaction is adsorbed or bound to the surface of the substrate by chemical bonding (for example, covalent bonding) to form the monolayer layer 20 on the surface of the substrate (FIG. 2) reference). In addition, a compound having a structure represented by the general formula (1) can expose SR ₁ (for example, SLi) on the surface of the base material through L (for example, a linear carbon chain) serving as a spacer. To form a monomolecular film layer 20. Here, since the sulfur atom of SR ₁ can capture lithium ions on the surface of the base material, the sulfur atom plays a role as a positive electrode active material.

In the general formula (1), R ₁ represents a hydrogen atom, a lithium atom or a sodium atom. Further, a single bond and R _1, the sulfur atom together of a compound having a structure represented by the two general formulas (1) may be a compound connected with S-S bond (disulfide bond).

L represents a linking group containing a thienyl group .

Here, L is preferably a linking group having conductive performance, such as a compound in which π conjugation is linked. By setting L as a connecting group having a conductive performance, the ease of electron transfer between the positive electrode active material (sulfur atom) and the positive electrode current collector 10 is improved, and the internal resistance value is lowered to accelerate charge and discharge. Can be improved.
As the linking group having conductivity, a compound capable of forming a monomolecular film layer can be appropriately selected from the effects of the present invention, but from the viewpoint of improving discharge capacity, Li can be retained, for example, a sulfur atom, It is preferable that it is a linking group containing an oxygen atom or a nitrogen atom. Further, from the viewpoint of imparting conductivity, it is preferable to contain, for example, a hetero five-membered ring such as a thiophene ring, a furan ring, a pyrrole ring, cyclopentadiene, and silacyclopentadiene, and a unit containing a condensed ring thereof. Specifically, thiophene, thienothiophene, bithiophene, fluorene, silafluorene, carbazole, dithienocyclopentadiene, dithienosilacyclopentadiene, dithienopyrrole, benzodithiophene and the like can be mentioned. Among these, thiophene rings are particularly preferable because they are more conductive.
In addition, when using a compound having no conductivity as a linking group, the chain length of the linking group is shortened from the viewpoint of electron transferability, and the sulfur atom of SR ₁ on the substrate surface and the positive electrode are collected. It is preferable to reduce the distance to the current collector 10 as much as possible.

R ₂ represents a mosquito Rubokishi group.

Hereinafter, specific examples of the compound having the structure represented by the general formula (1), the present invention, exemplary compounds shown below: (1) is used. Although n in a formula can be selected suitably, Preferably it is 1-7. In addition, Exemplified compounds other than Exemplified compound (1) shown below make a reference example.

(2.1) Synthesis Example of Compound (1) The organic compound according to the present invention can be easily synthesized according to a conventionally known synthesis method. As an example, a method of synthesizing n = 4 compounds of the exemplified compound (1) (also referred to as compound (1)) is shown.

(2.1.1) Synthesis of Intermediate 1 In a 100 ml recovery flask, Raw material 1, 2, 2 ': 5', 2 ": 5", 2 "'-quaterthiophene (3.0 g, 9.1 mmol) A solution of POCl ₃ (2.0 g, 14 mmol) in DMF (50 ml) was heated and stirred at 100 ° C. for 5 hours.
Thereafter, the solution was transferred to a separatory funnel for extraction. After addition of saturated brine and separation into an organic phase and an aqueous phase, the organic phase was taken out and evaporated under reduced pressure. The obtained solid was purified by silica gel column chromatography to obtain a white solid of Intermediate 1 (2.6 g, yield 80%).

(2.1.2) Synthesis of Intermediate 2 In a 50 ml recovery flask, a solution of Intermediate 1 (2.6 g, 7.3 mmol) and K ₂ CrO ₄ (4.2 g, 22 mol) in DMF (30 ml) It heat-stirred at 100 degreeC for 10 hours.
Thereafter, the solution was transferred to a separatory funnel for extraction. After addition of saturated brine and separation into an organic phase and an aqueous phase, the organic phase was taken out and evaporated under reduced pressure to obtain a white solid (2.5 g, yield 92%) of Intermediate 2.

(2.1.3) Synthesis of Intermediate 3 In a 50 ml recovery flask, a solution of Intermediate 2 (2.5 g, 6.7 mmol), NBS (1.8 g, 10 mol) in DMF (30 ml) at 100 ° C. The mixture was heated and stirred for 5 hours.
Thereafter, the solution was transferred to a separatory funnel for extraction. After addition of saturated brine and separation into an organic phase and an aqueous phase, the organic phase was taken out and evaporated under reduced pressure. The obtained solid was purified by silica gel column chromatography to obtain a yellow solid of intermediate 3 (3.0 g, yield 66%).

(2.1.4) Synthesis of Compound (1) In a 50 ml recovery flask, a solution of Intermediate 3 (3.0 g, 6.6 mmol), NaSH (0.45 g, 8.0 mol) in DMF (30 ml), The mixture was heated and stirred at 25 ° C. for 12 hours.
Thereafter, the solution was transferred to a separatory funnel for extraction. Saturated brine was added to separate into an organic phase and an aqueous phase, and then the organic phase was taken out and evaporated under reduced pressure to obtain a white solid (1.1 g, 42% yield) of compound (1).

(2.2) Method of Forming Monolayer Layer 20 The method of forming the monolayer layer 20 is not particularly limited as long as it is a method by which a large number of compounds represented by General Formula (1) can be bonded onto the substrate surface. It can be formed on a substrate by a known method. In addition, from the viewpoint of forming a monomolecular film at a high density on the surface of the substrate and enabling more lithium ions to be delivered, forming the monomolecular film layer 20 with a self-assembled monolayer (SAM) Is preferred. For example, the substrate is immersed in Zr tetra n-butoxide solution (ZTB, 80% 1-butanol solution) or Ti tetra n-butoxide solution (TTB, 80% 1-butanol solution) to form a monomolecular film of these metals, and then the metal is formed. A monomolecular film can be formed by treatment with an alkoxide and immersing the desired compound in a solution. Alternatively, a monomolecular film may be formed by forming SiH- (OH) ₃ on a substrate and reacting with a compound having, for example, Phenylacetylene (PA).

(3) Electrolyte layer 30
The electrolyte layer 30 is not particularly limited, and is formed of, for example, a so-called gel electrolyte layer or a solid electrolyte layer in the form of gel or solid.
As a gel or solid form, for example, a gel or solid form formed by incorporating a lithium salt or a solvent in which a lithium salt is dissolved in a polymer substance or an organic-inorganic composite substance of organic and inorganic substances. Can be mentioned. Moreover, as another gel-like or solid-like form, the gel-like or solid-like form etc. which were formed by polymerizing the mixture containing a polymerizable monomer, a polymerization initiator, and a lithium salt, etc. are mentioned.

  Examples of the polymer substance include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-ethylene copolymer, vinylidene fluoride-monofluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer. Polymers, vinylidene fluoride polymers such as vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, acrylonitrile-methyl methacrylate copolymer, acrylonitrile- Methyl acrylate copolymer, acrylonitrile-ethyl methacrylate copolymer, acrylonitrile-ethyl acrylate copolymer, acrylonitrile-methacrylic acid copolymer, acrylonitrile-acrylic acid copolymer, acrylonitrile Lil - acrylonitrile polymers such as vinyl acetate copolymer, further polyethylene oxide, ethylene oxide - propylene oxide copolymers, and polymers of these acrylates body or methacrylate body thereof.

  The organic-inorganic composite material is a material in which an organic substance and an inorganic substance are physically mixed or chemically formed, and the inorganic substance is preferably an inorganic oxide fine particle.

  As inorganic substances, silicon oxide, titanium oxide, zinc oxide, aluminum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, indium oxide, lead oxide, scandium oxide, oxide Yttrium, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, iron oxide, zirconium oxide, And clay, tin oxide, tungsten oxide, aluminum phosphate and the like.

  As the organic substance, polyethylene oxide having an alkoxysilyl group, an alkoxytitanate group, an alkoxyaluminate group, an alkoxyzirconate group which can modify the surface of the inorganic oxide fine particles by a chemical bond in addition to the above-mentioned polymer substance Ethylene oxide-propylene oxide copolymer is mentioned.

  As said polymeric monomer, the monomer which has unsaturated double bonds, such as an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, is mentioned, for example. Specific examples of the monomer include acrylic acid, methyl acrylate, ethyl acrylate, ethoxyethyl acrylate, methoxyethyl acrylate, ethoxyethoxyethyl acrylate, polyethylene glycol monoacrylate, ethoxyethyl methacrylate, methoxyethyl methacrylate, ethoxyethoxyethyl methacrylate, Polyethylene glycol monomethacrylate, N, N-diethylaminoethyl acrylate, N, N-dimethylaminoethyl acrylate, glycidyl acrylate, allyl acrylate, acrylonitrile, N-vinylpyrrolidone, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate , Polyethylene glycol Diac relay Other than diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polyalkylene glycol diacrylate and polyalkylene glycol dimethacrylate, trimethylolpropane alkoxylate triacrylate and pentaerythritol alkoxylate triacrylate And trifunctional or higher functional monomers such as pentaerythritol alkoxylate tetraacrylate and ditrimethylolpropane alkoxylate tetraacrylate.

  As the electrolyte composition having the above-mentioned gel form or solid form, it is thermoreversible to be fluidized by heating and non-fluidized at normal temperature, or fluidized by shear force even at normal temperature, and to stand still It is preferable to have thixotropy to defluidize.

  The non-fluidization to a gel or solid form using a polymerizable monomer is carried out by polymerizing the above-mentioned monomers by heat, ultraviolet light, electron beam or the like.

In this case, it is preferable to use a polymerization initiator in order to effectively advance the polymerization.
As a polymerization initiator, in addition to benzoin, benzyl, acetophenone, benzophenone, Michler's ketone, biacetyl, benzoyl peroxide, t-butyl peroxy neodecanoate, α-cumyl peroxy neo decanoate, t-hexyl peroxy Peroxy neodecanoates such as neodecanoate, 1-cyclohexyl-1-methylethyl peroxy neodecanoate, t-amyl peroxy neodecanoate, etc., t-butyl peroxy neoheptanoate, α Peroxy neoheptanoates such as cumylperoxy neoheptanoate, t-hexylperoxy neoheptanoate, 1-cyclohexyl-1-methylethylperoxy neoheptanoate, t-amyl peroxyheptanoate and the like And the like.

  As the polymerizable monomer, in addition to the above, it is also possible to use a polymer which is produced by polycondensation of polyester, polyamide, polycarbonate, polyimide etc., a monomer which produces a polymer produced by polyaddition such as polyurethane, polyurea etc. it can.

(4) Negative electrode 40
The negative electrode 40 is not particularly limited, and any negative electrode generally used in all solid lithium ion batteries can be used.
The negative electrode 40 may be only a negative electrode active material, but may be mixed with a binder, a conductive material, an electrolyte, and the like. When a lithium alloy such as Sn or Si is used as the negative electrode 40, the problem of conductivity is eliminated, and the capacity is further increased. It is also possible to use In as the negative electrode 40. Furthermore, the negative electrode 40 may partially include the electrolyte layer 30.
As the negative electrode 40, a carbon-based negative electrode material used in a liquid lithium ion battery can also be used. However, since these have no lithium ion, pre-doping is required.

(5) Negative electrode current collector 50
The negative electrode current collector 50 is not particularly limited as long as it has metallic conductive performance, but Al, Ag, Cu, etc. can be used, and it is determined by the adhesive performance with the negative electrode 40.
As the negative electrode current collector 50, Cu, Ni, Ti or stainless steel is preferable, and Cu or a Cu alloy is more preferable.

Examples of the present invention will be specifically described below. However, the present invention is not limited by these. Examples 1 and 2 are used as reference examples.

[Production of all solid lithium ion battery sample]
(1) Example 1
(1.1) Preparation of Positive Electrode and Preparation of Negative Electrode An aluminum Mylar film (having an arithmetic average roughness Ra of 2) in which an aluminum oxide layer by natural oxidation is formed with a thickness of 5.0 nm as a positive electrode current collector. .7 nm) were prepared. The aluminum mylar film was immersed in tetra-n-butoxyzirconium (80% 1-butanol solution) for 30 minutes. Then, it was immersed in a 1% methanol solution of 2,2'-dithiodibenzoic acid at 60 ° C. for 1 hour, pulled out of the solution, and thoroughly washed with methanol. Next, the film was heated in an oven at 100 ° C. for 1 hour, cooled to room temperature, and then subjected to the same treatment again to obtain an aluminum mylar film in which a self-assembled monolayer was formed on the surface.
Here, it was confirmed by the measurement using an ellipsometer that an ultra-thin film having a thickness of 1.0 nm was formed on the above-mentioned aluminum mylar film. In addition, ESCA analysis confirmed that the ultrathin film was a monomolecular film formed of 2,2'-dithiodibenzoic acid.
Indium (In) foil was prepared as a negative electrode.

(1.2) Preparation of Electrolyte (Sulphide Solid Electrolyte) Li ₂ S (made by Idemitsu Kosan Co., Ltd .: purity 99.9% or more) and P ₂ S ₅ (purity 99% made by Aldrich) in a molar ratio of 75:25 It was put into a planetary ball mill at a ratio, and dry mechanical milling was performed.
The planetary ball mill used Pulverisette P-7 manufactured by Fritsch. The pot and balls were made of zirconium oxide, and a mill was used in which 500 balls of 4 mm in diameter were contained in a 45 ml pot.
Dry mechanical milling was carried out at a rotational speed of 500 rpm, at room temperature, in a dry nitrogen glove box for 8 hours.

(1.3) Production of All Solid Lithium Ion Battery The positive electrode, the electrolyte and the negative electrode were sequentially stacked, and a pressure of 70 MPa / cm ² was applied by a press. Thereafter, these laminates were sealed with aluminum foil to manufacture an all solid lithium ion battery.

(2) Example 2
The surface of the aluminum mylar film of Example 1 was surface-treated with 5% NaOH, and the arithmetic average roughness Ra was 5.2 nm. An all solid lithium ion battery was manufactured in the same manner as in Example 1 except for the above.

(3) Example 3
An all solid lithium ion battery was manufactured in the same manner as in Example 1, except that the compound of Example 1 (2,2'-dithiodibenzoic acid) was changed to the compound of n = 4 in Example Compound (1). Manufactured.

(4) Comparative Example 1
Li ₂ S (manufactured by Idemitsu Kosan Co., Ltd .: purity of at least 99.9%) was used as the electrode material of the positive electrode. Ketjen black (EC 300J manufactured by Lion Corporation) was mixed with Li ₂ S at a mixing ratio of 9 to 1 as a conductive additive, and then dispersed in water to form a slurry. The slurry was applied to an aluminum foil as a positive electrode current collector and dried to prepare a 50 μm thick positive electrode.
An all solid lithium ion battery was manufactured by the same manufacturing method as in Example 1 except for the above.

[Evaluation of sample]
For each sample of the all-solid-state lithium ion battery obtained above, the condition 1 were charged and discharged measured in (current density 0.3 mA / cm ²⁾ and condition 2 (current density of 30 mA / cm ^2), measured respectively discharge capacity did.
Moreover, about the discharge capacity (mAh / g) in the current density of conditions 1 and 2, the capacity ratio by the difference in current density was evaluated. Here, the discharge capacity ratio (%) in the table was calculated using the following equation.
Discharge capacity ratio (%) = (discharge capacity of condition 2) ÷ (discharge capacity of condition 1) × 100

From Table 1 , it was found that the all-solid-state lithium ion battery ( Example 3 ) of the present invention had a sufficient discharge capacity for use, and the ultrathin lithium secondary battery was in operation. Moreover, in Example 1 and Example 2 (reference example) , especially discharge capacity became large. It is considered that this is because a large number of lithium ion transferable molecules could be bound to the substrate surface.

In addition, it was found that even when the current density was changed, a decrease in discharge capacity hardly occurred. The reason why the decrease in discharge capacity hardly occurs is that the layer thickness of the monomolecular film formed on the positive electrode current collector and the electrode material used for forming a single molecule are uniform, so that they easily reversibly react with the positive electrode active material. It is considered that the utilization rate of the positive electrode active material is high.
On the other hand, in Comparative Example 1, since the thickness of the positive electrode is thinner than usual and the region where the positive electrode active material adds and desorbs lithium ions is scarce, it is considered that the utilization of the positive electrode active material is low. Moreover, as the discharge capacity increases, the range of the irreversible reaction increases, and it is considered that the utilization of the positive electrode active material decreases.

  In addition, it was found that the all-solid-state lithium ion battery in which the surface of the positive electrode current collector was roughened (Example 2) was less likely to cause a decrease in discharge capacity. It is considered that this is because the positive electrode material has higher adhesion and higher density to the substrate surface due to the anchor effect, which leads to the improvement of the discharge capacity and the stabilization of the utilization of the positive electrode active material.

  In addition, it was found that the all-solid-state lithium ion battery (Example 3) in which the monomolecular film layer was formed using the compound of n = 4 of the exemplified compound (1) was less likely to cause a decrease in discharge capacity. This is considered to be because the conductivity of the compound forming the thin film is high, and the utilization of the positive electrode active material is further improved.

In addition, if the battery electrode material of the present invention as described above is used, the positive electrode active material can be directly formed on the current collector as the positive electrode material, so that the area can be increased.
In addition, when the battery electrode material of the present invention is used, it has no crystal structure and does not have toughness unlike the inorganic positive electrode material, so that it can be used in a flexible form assuming bending.
In addition, when the battery electrode material of the present invention is used, the compound is stable, and does not self-ignite even in a high temperature state, so that the safety is high.

1 all solid lithium ion battery 10 positive electrode current collector 20 monolayer film layer 30 electrolyte layer 40 negative electrode 50 negative electrode current collector

Claims (5)

A monomolecular film is formed using a compound having a structure represented by the following general formula (1) on a conductive base material surface of a conductive base material at least a part of which is a metal oxide. An electrode material for a battery characterized by
General formula (1) R ₁ S-L-R ₂
(Wherein, R ₁ represents a hydrogen atom, a lithium atom or a sodium atom. Moreover, the sulfur atoms of the compounds having the structures represented by two general formulas (1), where R ₁ is a single bond, optionally a compound connected with -S bond (disulfide bond) .L is a thienyl group represents including linking group, R ₂ represents a mosquito Rubokishi group.) The battery electrode material according to claim 1, wherein the monolayer is a self-assembled monolayer. Wherein the substrate surface is aluminum oxide (Al 2 _{O 3)} or indium-tin oxide cell electrode material according to claim 1 or claim 2, characterized in that it comprises (ITO). The arithmetic mean roughness Ra of the said base-material surface in which the said monomolecular film in the said electroconductive base material is formed is 5 nm or more, The claim is any one of Claim 1 to 3 characterized by the above-mentioned. Battery electrode material. An all solid lithium ion battery comprising the battery electrode material according to any one of claims 1 to 4 .

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