JP4516359B2 - Anode for non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to a negative electrode for a non-aqueous electrolyte secondary battery. More specifically, the present invention relates to a non-aqueous electrolyte secondary battery having a high current collecting property and preventing an active material from falling off due to occlusion / release of lithium ions and improving cycle life. The present invention relates to a negative electrode for a secondary battery.

  It has been proposed to arrange an elastic body in a non-aqueous electrolyte secondary battery. For example, a negative electrode made of a substance that absorbs and releases lithium, a positive electrode, and an electrode group formed by winding a separator in an elliptical spiral shape are housed in a battery case. A non-aqueous electrolyte secondary battery in which a liquid elastic body is arranged is known (see Patent Document 1). In this battery, when the active material expands and contracts as the charge / discharge cycle progresses and the battery swells, the battery absorbs the swelling by an elastic body to prevent an increase in the internal resistance of the battery and a swelling of the battery. It is.

  Further, in the lithium ion secondary battery in which the positive and negative electrodes are pellet type, a lithium ion secondary battery in which an elastic body whose surface is covered with a conductor is disposed between the positive electrode and the positive electrode can and between the negative electrode and the negative electrode can. It is known (see Patent Document 2). In this battery, when a positive electrode, a negative electrode pellet, and the like are warped, the elastic body absorbs the warping and attempts to ensure electrical contact. Moreover, the stress at the time of caulking the positive electrode can and the negative electrode can is relaxed by an elastic body to prevent cracking of the positive and negative electrode pellets.

  According to the battery, although the stress generated by the expansion and contraction of the active material accompanying charge / discharge can be alleviated to some extent, the level has not yet reached a satisfactory level. Therefore, the active material is pulverized by the stress caused by expansion and contraction, and cannot be prevented from falling off from the electrode.

JP-A-8-55637 Japanese Patent Laid-Open No. 11-144761

  Accordingly, an object of the present invention is to provide a negative electrode for a non-aqueous electrolyte secondary battery that can eliminate the various drawbacks of the above-described conventional technology.

The present invention comprises an active material layer, a current collecting surface layer formed on one surface side thereof, and an elastic film disposed on the other surface side,
In the surface layer for current collection, a large number of fine voids that are open in the surface and extend in the thickness direction are formed,
The active material layer is configured to include particles of an active material, and a material having a low lithium compound forming ability permeates throughout the thickness direction of the active material layer. The object is achieved by providing a negative electrode for a non-aqueous electrolyte secondary battery.

  According to the negative electrode of the present invention, since the stress generated due to the expansion and contraction of the particles of the active material is relieved by the elastic film, the active material is effectively prevented from being pulverized and falling off the electrode. The falling off of the active material is more effectively prevented by the current collecting surface layer. In addition, since the active material is not exposed on the surface of the electrode and is embedded in the conductive current collecting surface layer, it is effective that an electrically isolated active material exists. It is prevented and sufficient current collecting property can be obtained.

  The present invention will be described below based on preferred embodiments with reference to the drawings. FIG. 1 schematically shows the structure of an embodiment of the negative electrode for a non-aqueous electrolyte secondary battery of the present invention. The negative electrode 1 of this embodiment has a pair of negative electrode precursor 2 and the elastic film 3 as the basic structural member. The elastic film 3 is sandwiched between the negative electrode precursors 2.

  The negative electrode precursor 2 includes a current collecting surface layer 4 and an active material layer 5 disposed on one surface of the surface layer 4. As shown in FIG. 1, the elastic film 3 is sandwiched between the negative electrode precursors 2 so that the active material layers 5 of the negative electrode precursors 2 face each other and the surface layer 4 faces outward. As is clear from FIG. 1, the negative electrode 1 has a current collector thick film conductor (for example, a metal foil or expanded metal having a thickness of about 12 to 35 μm) that has been used for a conventional negative electrode. Not done.

  The current collecting surface layer 4 is conductive and has a current collecting function. The current collecting surface layer 4 is also used to prevent the active material contained in the active material layer 5 from being pulverized and falling off due to expansion and contraction of the active material due to occlusion and release of lithium ions. ing. Note that the pulverization and dropping of the active material is prevented by an elastic film described later.

  The current collecting surface layer 4 is made of a conductive material. The current collecting surface layer 4 is preferably made of a metal that can be a current collector of a non-aqueous electrolyte secondary battery. In particular, it is preferably made of a metal that can be a current collector of a lithium secondary battery. An example of such a metal is a metal material having a low lithium compound forming ability. Specific examples include copper, nickel, iron, cobalt, and alloys of these metals. Of these metals, it is particularly preferable to use copper and nickel or an alloy thereof. From the viewpoint of increasing the strength of the negative electrode 1, nickel is preferably used. The two current collecting surface layers 4 may be made of the same or different materials. “Lithium compound forming ability is low” means that lithium does not form an intermetallic compound or solid solution, or even if formed, lithium is in a very small amount or very unstable.

  Each surface layer 4 for current collection is thinner than the thick film conductor for current collection used in conventional electrodes. Specifically, a thin layer of about 0.3 to 10 μm, particularly about 1 to 5 μm is preferable. As a result, the active material layer 5 can be continuously and uniformly coated with the minimum necessary thickness. As a result, it is possible to prevent the active material pulverized due to charge / discharge from falling off. The thin surface layer 4 in the above range is preferably formed by electrolytic plating as will be described later. The two surface layers 4 may have the same thickness or may be different.

  Each current collecting surface layer 4 has a large number of fine voids 6 that are open in the surface and extend in the thickness direction. The fine void 6 exists in the surface layer 4 so as to communicate with the active material layer 5. By forming the fine voids 6, the non-aqueous electrolyte can sufficiently penetrate into the active material layer 5, and the reaction with the active material occurs sufficiently. The fine void 6 is a fine one having a width of about 0.1 μm to about 10 μm when the surface layer 4 is observed in cross section. Although fine, the fine gap 6 has a width that allows the non-aqueous electrolyte to penetrate. However, since the nonaqueous electrolytic solution has a smaller surface tension than the aqueous electrolytic solution, it can sufficiently penetrate even if the width of the fine gap 6 is small. The fine voids 6 are preferably formed at the same time when the current collecting surface layer 4 is formed by electrolytic plating.

When viewed in plan by electron microscopic observation of the surface of the current collecting surface layer 4, the average open area of the micropores 6 is 0.1 to 50 [mu] m ^2, preferably 0.1 to 20 [mu] m ^2, more preferably 0 About ⁵ to 10 μm ² . By setting the opening area within this range, it is possible to effectively prevent the active material from falling off while ensuring sufficient permeation of the non-aqueous electrolyte. Further, the charge / discharge capacity can be increased from the initial stage of charge / discharge. From the viewpoint of more effectively preventing the active material particles from falling off, the average pore area is 0.1 to 50%, particularly 0.1 to 20%, of the maximum cross-sectional area of the active material particles. Is preferred. The maximum cross-sectional area of the particles of the active material means the maximum cross-sectional area when the particle diameter (D ₅₀ value) of the particles of the active material is measured and the particles are regarded as a sphere having a diameter of D ₅₀ value.

  When the surface of the current collecting surface layer 4 is viewed in plan by electron microscope observation, the ratio of the total opening area of the fine voids 6 to the area of the observation field (this ratio is referred to as the opening ratio) is 0.1 to 0.1. 20%, preferably 0.5 to 10%. This reason is the same reason as setting the aperture area of the fine gap 6 within the above range. Furthermore, for the same reason, when the surface of the current collecting surface layer 4 is viewed in plan by electron microscope observation, no matter what observation field is taken, 1 to 20,000 in a 100 μm × 100 μm square field range, In particular, it is preferable that 10 to 1,000, especially 50 to 500 fine voids 6 exist.

  The active material layer 5 located immediately inside the current collecting surface layer 4 includes active material particles 7 having a high lithium compound-forming ability. The active material layer 5 is formed by applying a conductive slurry containing active material particles 7. Examples of the active material include silicon-based materials, tin-based materials, aluminum-based materials, and germanium-based materials. Since each active material layer 5 is covered with each current collecting surface layer 4, it is effectively prevented that the active material is pulverized and dropped off due to the occlusion and release of lithium ions. Since the active material can be in contact with the electrolytic solution through the fine gap 5, the electrode reaction is not hindered.

  Examples of the active material particles 7 include a) particles of silicon or tin, b) particles of at least silicon or tin and carbon, c) particles of silicon or tin and metal, and d) silicon or tin. Compound particles of metal, e) mixed particles of silicon or tin and metal and metal particles, and f) particles formed by coating the surface of silicon or tin particles with metal. . B), c), d), d), f) and f) particles are finer than silicon materials due to occlusion and release of lithium compared to b) There is an advantage that is further suppressed. Further, there is an advantage that electron conductivity can be imparted to silicon which is a semiconductor and has poor electron conductivity.

The active material particles 7 preferably have a maximum particle size of 50 μm or less, and more preferably 20 μm or less. Moreover, when the particle size of the particle 7 is expressed by a D ₅₀ value, it is preferably 0.1 to 8 μm, particularly preferably 1 to 5 μm. When the maximum particle size is more than 50 μm, the particles 7 are likely to fall off, and the life of the electrode may be shortened. There is no particular limitation on the lower limit of the particle size, and the smaller the better. In view of the method for producing the particles 7, the lower limit is about 0.01 μm. The particle size of the particles 7 is measured by a laser diffraction / scattering particle size distribution measuring device or an electron microscope.

  If the amount of the active material relative to the whole negative electrode 1 is too small, it is difficult to sufficiently improve the energy density of the battery. Conversely, if the amount is too large, the active material tends to fall off. Considering these, the amount of the active material is preferably 5 to 80% by weight, more preferably 10 to 50% by weight, and still more preferably 20 to 50% by weight with respect to the entire negative electrode 1. The thickness of the active material layer 4 can be appropriately adjusted according to the ratio of the amount of the active material to the whole negative electrode, and is not particularly critical in the present embodiment. The thickness in the case where the active material layer 5 includes the active material particles 7 is generally 1 to 100 μm, particularly about 3 to 40 μm.

  In the active material layer 5, a material having a low ability to form a lithium compound penetrates in the thickness direction of the active material layer 5. In particular, it is preferable to penetrate through the entire thickness direction. The active material particles 7 are present in the permeated material. That is, it is preferable that the active material particles 7 are not substantially exposed on the surface of the negative electrode 1 and are embedded in the current collecting surface layer 4. As a result, the adhesion between the active material layer 5 and the surface layer 4 becomes strong, and the falling off of the active material is further prevented. In addition, since electronic conductivity is ensured between the surface layer 4 and the active material through the material that has penetrated into the active material layer 5, an electrically isolated active material is generated, particularly in the deep part of the active material layer 5. The generation of an electrically isolated active material is effectively prevented, and the current collecting function is maintained. As a result, functional degradation as a negative electrode is suppressed. In addition, the life of the negative electrode can be extended. This is particularly advantageous when a material that is a semiconductor and has poor electron conductivity, such as a silicon-based material, is used as the active material.

  The material having a low ability to form a lithium compound penetrating in the thickness direction of the active material layer 5 is preferably the same material as the material constituting the current collecting surface layer 4. However, if the lithium compound forming ability is low, a material different from the material constituting the surface layer 4 may be used.

  The elastic film 3 interposed between the two active material layers 5 absorbs and relaxes the stress generated due to the expansion and contraction of the active material particles 7 so that the active material particles 7 are pulverized. Used to prevent. From this viewpoint, it is preferable that the elastic film 3 has sufficient elasticity in the thickness direction. For example, the elastic membrane 3 preferably has a linear expansion coefficient of 5 to 40, particularly 10 to 30. Examples of the material having such a linear expansion coefficient include natural rubber, styrene butadiene rubber, polyacrylonitrile, nitrile rubber, silicone rubber, polyisobutylene, fluorine rubber, and polyurethane rubber.

  Although it depends on the type of the active material, it is said that the change in the thickness of the active material layer due to expansion and contraction of the active material reaches about 200%. Therefore, the elastic film 3 preferably has a thickness of 10 to 60%, particularly 20 to 50% of the thickness of the active material layer 5 from the viewpoint of sufficiently absorbing and relaxing stress.

  The type of the elastic membrane 3 is not particularly limited as long as it is inactive with respect to the non-aqueous electrolyte. Further, the elastic film 3 may or may not have conductivity. When the elastic film 3 has conductivity and the conductive material having a low lithium compound forming ability permeates the entire thickness direction of the active material layer 5, the two current collecting surface layers 4 are Electrical conduction is made through the conductive material and the elasticity 3, and the electronic conductivity of the negative electrode 1 as a whole is further increased. That is, the negative electrode 1 as a whole has a current collecting function.

  It is also preferable that the elastic membrane 3 has a porous structure that allows the non-aqueous electrolyte to flow. As a result, the non-aqueous electrolyte flows between the two active material layers 5, and the two active material layers 5 are as if they were one layer of active material.

  The total thickness of the negative electrode 1 having the above configuration is preferably about 2 to 50 μm, particularly about 10 to 50 μm in consideration of maintaining the strength of the negative electrode 1 and increasing the energy density.

  Next, the preferable manufacturing method of the negative electrode 1 shown in FIG. 1 is demonstrated, referring FIG. First, the negative electrode precursor 2 is manufactured. For the production of the negative electrode precursor 2, a carrier foil 11 is prepared as shown in FIG. The carrier foil 11 is used as a support for manufacturing the negative electrode precursor 2. Further, the produced negative electrode precursors 2 are supported until they are joined, and used to improve the handleability of the negative electrode precursors 2. There are no particular restrictions on the material of the carrier foil 11. Since the carrier foil 11 is used as a support for manufacturing the negative electrode precursor 2, it is preferable that the carrier foil 11 has such a strength that no twist or the like occurs in the manufacturing process. Therefore, the carrier foil 11 preferably has a thickness of about 10 to 50 μm.

  It is preferable to use a conductive foil as the carrier foil 11. In this case, the carrier foil 11 may not be made of metal as long as it has conductivity. However, the use of the metal carrier foil 11 has an advantage that the carrier foil 11 can be melted, made into a foil and recycled after the production of the negative electrode precursor 2. When the metal carrier foil 11 is used, the carrier foil 11 is configured to include at least one metal of Cu, Ni, Co, Fe, Cr, Sn, Zn, In, Ag, Au, Al, and Ti. It is preferable.

  From the viewpoint of forming a large number of fine voids 6 in the current collecting surface layer 4, an aluminum foil or an aluminum alloy foil (hereinafter collectively referred to simply as an aluminum foil) is used as the carrier foil 11, and current collection is performed by the method described below. The surface layer 4 for use is preferably formed. As the aluminum foil, it is preferable to use a JIS standard 1N30 Al alloy (Al> 99.30%, Fe + Si <0.7%). Note that the lower limit of the Fe + Si concentration is Fe + Si> 0.01%, particularly Fe + Si> 0.1%. This Al alloy is one in which Al is the main component in the alloy and Fe and Si are uniformly dispersed in Al as a dispersion precipitation portion.

Prior to forming the current collecting surface layer 4 on the carrier foil 11 made of aluminum foil, a degreasing / etching process is performed to etch the Al portion of the carrier foil 11 while degreasing the surface of the carrier foil 11. The composition of the treatment liquid and the treatment conditions are, for example, as follows. Since aluminum is an amphoteric metal, alkali degreasing and etching are simultaneously performed by using a treatment liquid having the following composition.
NaOH: 15-45 g / l
・ Rochelle salt; 25-65 g / l
・ Na ₂ CO ₃ ; 25-65 g / l
Liquid temperature: 20-60 ° C, preferably 30-50 ° C
Processing time: 10 to 300 seconds Degreasing Etching rate 1 to 1.5 μm / min

As the degreasing / etching progresses, the aluminum on the surface of the carrier foil 11 is removed, and the minute protrusions 12 containing impurities such as Fe and Si contained in the aluminum are exposed (FIG. 2B). reference). The degreasing / etching process is performed until the protruding portion 12 is exposed. If the processing time is too long, Al ₂ O ₃ is formed and interferes with the etching process, so care must be taken not to oversaturate the etching.

When the degreasing / etching process is completed, the carrier foil 11 is washed with running water at room temperature to remove the degreasing / etching solution. Next, electrolytic plating is performed on the carrier foil 11. For example, when performing nickel plating, a plating bath (Watt bath) having the following composition or a nickel sulfamate bath can be used.
NiSO ₄ .6H ₂ O; 150 to 300 g / l
NiCl ₂ .6H ₂ O; 50 to 250 g / l
_{· H 3 BO 3; 30~40g /} l

When copper plating is performed, a plating bath (CuSO ₄ bath) having the following composition or a copper pyrophosphate bath can be used.
CuSO ₄ .5H ₂ O; 150 to 350 g / l
・ H ₂ SO ₄ ; 50 to 250 g / l
In this case, the current density is preferably ^{2 to} 50 A / dm ² , particularly preferably 10 to 30 A / dm ² . It is preferable to use an insoluble electrode (DSE) for the anode. A DC power source is used as the power source.

  A current collecting surface layer 4 having a predetermined thickness is formed on the carrier foil 11 by electrolytic plating (see FIG. 2C). The mechanism by which many fine voids 6 are formed in the current collecting surface layer 4 is as follows. In the initial stage of electroplating, electrodeposition occurs starting from the protrusions 12 exposed on the surface of the carrier foil 11, and metal particles of plated metal are generated. Then, the generated metal particles grow, and the grown metal particles continue to grow further. During this growth, pores are created between the metal particles. These holes are filled with the growth of the metal particles, but microscopically there are fine holes between the metal particles. These fine holes become fine voids penetrating the current collecting surface layer 4. In this way, a current collecting surface layer having a large number of fine voids is formed on the carrier foil 11.

  Next, as shown in FIG. 2D, an active material layer 5 is formed on the current collecting surface layer 4 by applying a conductive slurry containing active material particles. The slurry contains active material particles, conductive carbon material or conductive metal material particles, a binder, a diluting solvent, and the like. Among these components, polyvinylidene fluoride (PVDF), polyethylene (PE), ethylene propylene diene monomer (EPDM), styrene butadiene rubber (SBR), polyacrylonitrile, and the like are used as the binder. As a diluting solvent, N-methylpyrrolidone, cyclohexane or the like is used. The amount of the active material in the slurry is preferably about 14 to 40% by weight. The amount of the conductive carbon material or conductive metal material particles is preferably about 0.4 to 4% by weight. The amount of the binder is preferably about 0.4 to 4% by weight. Moreover, it is preferable that the quantity of a dilution solvent shall be about 60 to 85 weight%.

  After the coating film of the slurry is dried and the active material layer 5 is formed, the carrier foil 11 on which the active material layer 5 is formed is immersed in a plating bath containing a metal material having a low lithium compound forming ability. Perform electrolytic plating. By immersion in the plating bath, the plating solution enters the active material layer 5 and reaches the interface between the active material layer 5 and the current collecting surface layer 4, and electrolytic plating is performed in this state. As a result, (a) a metal having a low lithium compound forming ability on the inside of the active material layer 5 and (b) the inner surface side of the active material layer 5 (that is, the surface side facing the current collecting surface layer 4). The material precipitates and permeates throughout the thickness direction of the active material layer 5. In this way, the negative electrode precursor 2 is formed on the carrier foil 11.

As conditions for electrolytic plating, for example, when copper is used as a metal material having a low ability to form a lithium compound, when using a copper sulfate solution, the concentration of copper is 30 to 100 g / l, and the concentration of sulfuric acid is 50 to 200 g / l. The chlorine concentration may be 30 ppm or less, the liquid temperature may be 30 to 80 ° C., and the current density may be 1 to 100 A / dm ² . When using a copper pyrophosphate solution, the concentration of copper is 2 to 50 g / l, the concentration of potassium pyrophosphate is 100 to 700 g / l, the liquid temperature is 30 to 60 ° C., the pH is 8 to 12, and the current density is 1. ~10A / dm ² and may be set. By appropriately adjusting these electrolysis conditions, the metal material penetrates throughout the thickness direction of the active material layer 5.

  Thus, the negative electrode precursor 2 provided with the current collecting surface layer 4 and the active material layer 5 in this order on the carrier foil 11 is formed. 2A and 2B, the elastic film 3 is sandwiched between the negative electrode precursors 2 so that the active material layers 5 in the negative electrode precursors 2 face each other as shown in FIG. Thereby, the negative electrode 1 provided with the elastic film 3 and both negative electrode precursors 2 is obtained. In this case, the elastic film 3 and the negative electrode precursors 2 may be simply overlapped. When the bonding between the elastic film 3 and the negative electrode precursor 2 is to be strengthened, these three members may be bonded together using a conductive adhesive material such as a conductive paste. Alternatively, these three members may be overlapped and then crimped by roll rolling. In addition, after superposing the elastic film 3 and the two negative electrode precursors 2, by winding them in a spiral shape, these three can be reliably fixed without using an adhesive or rolling. .

  Finally, as shown in FIG. 2 (f), the negative electrode precursor 2 is peeled and separated from the carrier foil 11 at the interface between the current collecting surface layer 4 and the carrier foil 11. Thereby, the intended negative electrode 1 is obtained. When an aluminum foil is used as the carrier foil 11, the surface of the foil is passivated and an oxide film is formed between the degreasing / etching process and the formation of the current collecting surface layer 4. Since this oxide film acts as a release layer, the carrier foil 11 is successfully peeled off from the current collecting surface layer 4.

The negative electrode of the present embodiment thus obtained is used with a known positive electrode, separator, and non-aqueous electrolyte solution to form a non-aqueous electrolyte secondary battery. The positive electrode is prepared by suspending a positive electrode active material and, if necessary, a conductive agent and a binder in an appropriate solvent to prepare a positive electrode mixture, applying this to a current collector, drying it, then rolling and pressing, and further cutting. It is obtained by punching. As the positive electrode active material, conventionally known positive electrode active materials such as lithium nickel composite oxide, lithium manganese composite oxide, and lithium cobalt composite oxide are used. As the separator, a synthetic resin nonwoven fabric, polyethylene, polypropylene porous film, or the like is preferably used. In the case of a lithium secondary battery, the nonaqueous electrolytic solution is a solution in which a lithium salt that is a supporting electrolyte is dissolved in an organic solvent. Examples of the lithium _{salt, LiBF 4, LiC1O 4, LiA1Cl} 4, LiPF 6, LiAsF 6, LiSbF 6, LiSCN, LiC1, LiBr, LiI, etc. _{LiCF 3 SO 3, LiC 4 F} 9 SO 3 are exemplified.

  The present invention is not limited to the embodiment. For example, in the above embodiment, the negative electrode 1 is composed of the pair of negative electrode precursors 2 and the elastic film 3 sandwiched between them, but the negative electrode 1 ′ shown in FIG. Good. The negative electrode 1 ′ includes an active material layer 5, a current collecting surface layer 4 formed on one side of the active material layer 5, an elastic film 3 disposed on the other side and having the surface exposed to the outside. It has. In the negative electrode 1 ′, the elastic film 3 not only has an action of absorbing and relaxing stress generated due to expansion and contraction of the active material, but also removes the active material in the same manner as the current collecting surface layer 4. It has an action to prevent. When the elastic membrane 3 has a porous structure that allows the non-aqueous electrolyte to flow, the non-aqueous electrolyte flows to the active material layer 5 through the elastic membrane 3, so that the surface layer 4 side There is an advantage that the electrode reaction can be caused not only from the elastic membrane 3 side but also from the elastic membrane 3 side. That is, when the elastic film 3 has a porous structure, the elastic film 3 has the same function as the current collecting surface layer 4.

It is a schematic diagram which shows the structure of one Embodiment of the negative electrode of this invention. It is process drawing which shows the method of manufacturing the negative electrode shown in FIG. It is a schematic diagram which shows the structure of another embodiment of the negative electrode of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Negative electrode for non-aqueous electrolyte secondary batteries 2 Negative electrode precursor 3 Elastic film 4 Surface layer for current collection 5 Active material layer 6 Fine void 7 Active material particles

Claims (7)

An active material layer, a current collecting surface layer formed on one surface side thereof, and an elastic film disposed on the other surface side,
In the current collecting surface layer, a large number of fine voids that are open in the surface and extend in the thickness direction are formed,
The active material layer is configured to include particles of an active material, and a material having a low ability to form a lithium compound penetrates over the entire thickness direction of the active material layer. Negative electrode for non-aqueous electrolyte secondary battery. A pair of negative electrode precursors comprising the active material layer and the surface layer for current collection formed on one surface side of the active material layer, and the elastic film;
The non-aqueous electrolysis according to claim 1, wherein the elastic film is sandwiched between the negative electrode precursors so that the active material layers in each negative electrode precursor face each other and the current collecting surface layer faces outward. Negative electrode for liquid secondary battery.   3. The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1, wherein the elastic membrane has a porous structure that allows the non-aqueous electrolyte to flow.   The negative electrode for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein the current collecting surface layer has a thickness of 0.3 to 10 µm.   The negative electrode for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein the current collecting surface layer is made of a metal material having a low ability to form a lithium compound.   The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1, wherein the active material layer is formed by applying a conductive slurry containing particles of the active material. The negative electrode for a nonaqueous electrolyte secondary battery according to claim 1, wherein the current collecting surface layer is formed by electrolytic plating.

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