WO2014141962A1

WO2014141962A1 - All-solid-state battery

Info

Publication number: WO2014141962A1
Application number: PCT/JP2014/055593
Authority: WO
Inventors: 悟史重松; 三花福島
Original assignee: 株式会社村田製作所
Priority date: 2013-03-11
Filing date: 2014-03-05
Publication date: 2014-09-18

Abstract

Provided is an all-solid-state battery which uses a sulfide as a solid electrolyte, and which is capable of expanding the scope of applicable collector materials. This all-solid-state battery (10) is provided with: a positive electrode layer (11) and/or a negative electrode layer (13); a solid electrolyte layer (12) that is laminated on one surface of the electrode layer; a collector (15) that is arranged on the other surface of the electrode layer, said other surface being on the reverse side of the one surface; and an intervening layer (14) that is interposed between the electrode layer and the collector (15). The electrode layer contains an electrode active material and a sulfide solid electrolyte. The intervening layer (14) contains a material which is less reactive with the sulfide solid electrolyte in comparison to copper.

Description

All solid battery

The present invention generally relates to an all-solid battery, and more particularly to an all-solid battery in which at least one of a positive electrode layer and a negative electrode layer includes an electrode active material and a sulfide solid electrolyte.

In recent years, with the development of portable electronic devices such as mobile phones and laptop computers, the demand for secondary batteries as cordless power sources for these electronic devices has increased. Among them, development of lithium ion secondary batteries that have high energy density and can be charged and discharged has been actively conducted.

Also, as the functions of portable electronic devices increase, their power consumption has increased remarkably. In order to cope with this increase in power consumption, a large-capacity lithium ion secondary battery has become necessary.

In the lithium ion secondary battery, a metal oxide such as lithium cobaltate as a positive electrode active material, a carbon material such as graphite as a negative electrode active material, and a lithium hexafluorophosphate dissolved in an organic solvent as an electrolyte, that is, Organic solvent electrolytes are generally used. In the battery having such a configuration, an attempt has been made to increase the internal energy by increasing the amount of the active material, further increase the energy density, and improve the output current. It is also expected to increase the size of the battery and mount the battery in a vehicle.

However, in the lithium ion secondary battery having the above configuration, since the organic solvent used for the electrolyte is a flammable substance, there is a risk that the battery may ignite. For this reason, it is required to further increase the safety of the battery.

Therefore, one measure for improving the safety of the lithium ion secondary battery is to use a solid electrolyte instead of the organic solvent electrolyte. As the solid electrolyte, it has been studied to apply organic materials such as polymers and gels, and inorganic materials such as glass and ceramics. Among them, an all-solid secondary battery using an inorganic material mainly composed of nonflammable glass or ceramics as a solid electrolyte has been proposed and attracted attention.

When producing a sulfide-based solid battery using sulfide as a solid electrolyte, since sulfide is a highly reactive material, materials applicable to the current collector are limited.

For example, Japanese Unexamined Patent Application Publication No. 2010-33918 (hereinafter referred to as Patent Document 1) describes using aluminum, titanium, and stainless steel as a current collector in a sulfide-based solid battery.

Japanese Patent Laid-Open No. 2011-165467 (hereinafter referred to as Patent Document 2) uses stainless steel, aluminum, nickel, iron, titanium, and carbon as a positive electrode current collector in a sulfide-based solid battery. It is described that stainless steel, copper, nickel, and carbon are used as the current collector.

JP 2010-33918 A JP 2011-165467 A

However, although the aluminum described in Patent Document 1 and Patent Document 2 can be applied to the positive electrode current collector, it is not applicable to the negative electrode current collector because lithium ions are doped at a base potential. Moreover, since titanium described in Patent Document 1 and Patent Document 2 may react with a sulfide solid electrolyte, it cannot be used as a current collector. Furthermore, the stainless steels described in Patent Document 1 and Patent Document 2 do not react with the sulfide solid electrolyte, but are not suitable for the battery manufacturing process because of poor workability.

Since iron and copper described in Patent Document 2 may react with the sulfide solid electrolyte, they cannot be used as a current collector. Further, carbon described in Patent Document 2 is not suitable for a battery manufacturing process because it is difficult to obtain strength and flexibility as in metal foil when processed into a thin sheet alone.

Therefore, an object of the present invention is to provide an all solid state battery capable of expanding the application range of the current collector material in the all solid state battery using sulfide as a solid electrolyte.

As a result of various investigations on the configuration of the all-solid battery, the present inventors, when an intervening layer made of a limited material is disposed between the electrode layer and the current collector, the current collector reacts with the sulfide solid electrolyte. It has been found that the application range of the current collector material can be expanded. Based on this finding, the all solid state battery according to the present invention has the following characteristics.

An all-solid battery according to the present invention includes at least one of a positive electrode layer and a negative electrode layer, a solid electrolyte layer laminated on one surface of the electrode layer, and a surface opposite to the one surface of the electrode layer. A current collector disposed on the other side of the electrode, and an intervening layer interposed between the electrode layer and the current collector. The electrode layer includes an electrode active material and a sulfide solid electrolyte. The intervening layer includes a material that is less reactive with the sulfide solid electrolyte than copper.

In the all solid state battery of the present invention, the intervening layer preferably has conductivity with respect to electrons and does not have conductivity with respect to lithium ions.

The intervening layer preferably contains a carbon material.

The intervening layer preferably contains a metal.

Furthermore, the intervening layer preferably contains stainless steel or aluminum as a metal.

The all solid state battery of the present invention includes first and second batteries each including a laminate in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are sequentially laminated, and the first battery is a second battery. And a current collector is disposed between the positive electrode layer of the first battery and the negative electrode layer of the second battery, and the intervening layer is between the positive electrode layer of the first battery and the current collector, or It is preferable to intervene between the negative electrode layer of the second battery and the current collector.

Note that a part of the intervening layer preferably contains an electrical insulator.

According to the present invention, since the intervening layer interposed between the electrode layer and the current collector includes a material that is less reactive with the sulfide solid electrolyte than the copper, the current collector reacts with the sulfide solid electrolyte. Therefore, the application range of the current collector material can be expanded.

It is sectional drawing which shows typically the cross-section of an all-solid-state battery as one embodiment of this invention. It is sectional drawing which shows typically the cross-section of the all-solid-state battery which connected two unit cells in series as another embodiment of this invention. It is sectional drawing which shows typically the cross-section of an all-solid-state battery as another embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, an all-solid battery 10 according to an embodiment of the present invention is constituted by a single battery including a positive electrode layer 11, a solid electrolyte layer 12, and a negative electrode layer 13. The positive electrode layer 11 is disposed on one surface of the solid electrolyte layer 12, and the negative electrode layer 13 is disposed on the other surface opposite to the one surface of the solid electrolyte layer 12. In other words, the positive electrode layer 11 and the negative electrode layer 13 are provided at positions facing each other via the solid electrolyte layer 12, and the solid electrolyte layer 12 is interposed between the positive electrode layer 11 and the negative electrode layer 13. Each of positive electrode layer 11 and negative electrode layer 13 includes a sulfide solid electrolyte and an electrode active material, and solid electrolyte layer 12 includes a sulfide solid electrolyte. Each of the positive electrode layer 11, the solid electrolyte layer 12, and the negative electrode layer 13 is formed into a green sheet, a printed layer, a film, or the like from a solid-liquid mixture such as slurry, paste, or colloid by a sheet method, a printing method, or the like. Alternatively, it may be formed from a powder of each material by a compression molding method.

The solid electrolyte layer 12 is laminated on one surface of the negative electrode layer 13, and the current collector 15 is disposed on the other surface opposite to the one surface of the negative electrode layer 13. The intervening layer 14 is disposed so as to be interposed between the negative electrode layer 13 and the current collector 15. The intervening layer 14 includes a material that is less reactive with the sulfide solid electrolyte than copper (Cu). Although not shown, the solid electrolyte layer 12 is laminated on one surface of the positive electrode layer 11, and the current collector 15 is disposed on the other surface opposite to the one surface of the positive electrode layer 11. The layer 14 may be disposed so as to be interposed between the positive electrode layer 11 and the current collector 15. That is, the current collector 15 is disposed on the surface on the other side opposite to the surface on one side (the surface on which the solid electrolyte layer 12 is laminated) of at least one of the positive electrode layer 11 and the negative electrode layer 13 and interposed. The layer 14 may be disposed so as to be interposed between the electrode layer and the current collector 15. The intervening layer 14 is most preferably disposed so as to be interposed between each electrode layer of the positive electrode layer 11 and the negative electrode layer 13 and the current collector 15, and at least between the negative electrode layer 13 and the current collector 15. It is preferable to arrange so as to intervene.

In the all solid state battery 10 of the present invention configured as described above, the intervening layer 14 interposed between at least one of the positive electrode layer 11 and the negative electrode layer 13 and the current collector 15 is a sulfide solid electrolyte. And the current collector 15 does not react with the sulfide solid electrolyte contained in at least one of the positive electrode layer 11 and the negative electrode layer 13. The application range of the material of the current collector 15 can be expanded.

Since the intervening layer 14 can prevent the reaction between the sulfide solid electrolyte and the current collector 15, the following effects can be obtained. It is possible to prevent deterioration of battery characteristics due to deterioration of the solid electrolyte. In addition, since the electric resistance between the battery and the current collector can be lowered, a high output battery can be obtained. Furthermore, since the corrosion of the current collector 15 containing a metal can be prevented, the reliability of the battery characteristics can be improved.

The intervening layer 14 is preferably conductive to electrons and not conductive to lithium ions. With this configuration, it is possible to obtain electronic conductivity between the electrode layer and the current collector 15 and to prevent doping of lithium ions from the electrode layer to the current collector 15.

The intervening layer 14 preferably contains a carbon material. In this case, the intervening layer 14 can be formed by printing, coating, or the like. Examples of the carbon material that has electronic conductivity and does not occlude lithium include carbon black, ketjen black, acetylene black, vapor-grown carbon fiber, and activated carbon.

The intervening layer 14 preferably contains a metal. In this case, the intervening layer 14 having excellent electron conductivity can be formed. Examples of metals include cobalt (Co), nickel (Ni), platinum (Pt), zinc (Zn), tin (Sn), gold (Au), rhodium (Rh), aluminum (Al), and stainless steel. The intervening layer 14 containing metal is formed on the surface of the current collector 15 by plating, sputtering, vapor deposition, or the like, and particularly preferably formed by plating. It is preferable to form the intervening layer 14 by plating a nickel-phosphorus (Ni-P) alloy on the surface of the copper foil as the current collector 15. Especially as a metal contained in the intervening layer 14, since stainless steel and aluminum are general purpose materials, they are preferable. As a material of the foil of the current collector 15, copper or aluminum is particularly preferable.

Note that the intervening layer 14 may be configured to include a resin. Examples of the resin include acrylic resin, polyvinylidene fluoride, polytetrafluoroethylene, and styrene butadiene rubber. The intervening layer may be a resin having electronic conductivity such as polypyrrole or polythiophene.

The thickness of the intervening layer 14 is preferably as thin as possible in consideration of electric resistance, and may be a thickness that does not allow pores to be formed. The thickness of the intervening layer 14 is preferably about 100 nm to 10 μm. When the intervening layer 14 is formed by printing or coating, it is about several μm to 10 μm. When formed by plating, sputtering, or vapor deposition, the thickness is several hundred nm. About several μm.

By interposing the intervening layer 14 containing the above-described material between at least one of the positive electrode layer 11 and the negative electrode layer 13 and the current collector 15, the materials listed below are applied to the current collector 15. can do. Examples of the material of the current collector 15 include copper (Cu), iron (Fe), nickel (Ni), gold (Au), platinum (Pt), aluminum (Al), aluminum alloy, brass, and stainless steel. Can do. In particular, copper is more preferably used as a material for the current collector 15 in terms of workability, manufacturing cost, and electronic conductivity.

As shown in FIG. 2, the present invention can be applied to an all solid state battery in which a plurality of unit cells are connected in series as another embodiment of the present invention. The all solid state battery 20 includes two all

solid state batteries

10 and 10 each including a laminate in which a positive electrode layer 11, a solid electrolyte layer 12, and a negative electrode layer 13 are sequentially laminated. The two all

solid state batteries

10 and 10 are connected in series. A current collector 15 is disposed between the positive electrode layer 11 of one all solid state battery 10 disposed on the lower side and the negative electrode layer 13 of the other all solid state battery 10 disposed on the upper side. Intervening layer 14 is interposed between positive electrode layer 11 and current collector 15 of one all-solid battery 10, and is interposed between negative electrode layer 13 and current collector 15 of the other all-solid battery 10. . The intervening layer 14 is either between the positive electrode layer 11 and the current collector 15 of one all solid state battery 10 or between the negative electrode layer 13 and the current collector 15 of the other all solid state battery 10. It is also possible to intervene only.

With this configuration, the single current collector 15 can be used as a current collector for both positive and negative electrodes, and can also be used as a connection layer for two batteries. As a result, when a plurality of unit cells are stacked, the total thickness and weight can be reduced, the movement of lithium ions between the unit cells can be surely prevented, and deterioration of the battery performance can be prevented. it can.

As shown in FIG. 3, an all-solid battery 30 according to another embodiment of the present invention is composed of a single battery including a positive electrode layer 11, a solid electrolyte layer 12, and a negative electrode layer 13, and the negative electrode layer 13 and a current collector. The intervening layers 141 and 142 are interposed between the positive electrode layer 11 and the current collector 15, and the intervening layer 14 is interposed between the positive electrode layer 11 and the current collector 15. The intervening layers 14 and 141 have electronic conductivity. An intervening layer 142 having a shape surrounding the electrode is formed around the intervening layer 141 between the negative electrode layer 13 and the current collector 15. The intervening layer 142 has electrical insulation.

With this configuration, the electron conductive intervening layer 141 can prevent a reaction between the sulfide solid electrolyte contained in the positive electrode layer 11 and the negative electrode layer 13 and the current collector 15, and also has an electrically insulating property. The interposition layer 142 can prevent an electrical short circuit between the positive electrode side and the negative electrode side. Thus, it is preferable that a part of the intervening layer contains an electrical insulator.

In the all solid state battery 10 of the present invention, the positive electrode layer 11 includes a positive electrode active material, and the positive electrode active material is a kind of element selected from the group consisting of sulfur, lithium, manganese, iron, copper, and nickel. Are preferably included. The positive electrode layer 11 is made of, for example, a general active material (LiMO ₂ (M = Co, Ni, Mn, Li _1/3 Mn _2/3, etc.) or a polyanion-based material (LiFePO ₄ ). By including the positive electrode layer 11 thus configured, the crystal structure of the compound forming the positive electrode active material can be strengthened, and the energy density during discharge can be increased, that is, the discharge capacity can be increased. The charge / discharge cycle characteristics can be improved because the resistance during charge / discharge can be reduced, and in this case, the charge / discharge cycle characteristics are further improved by including Li ₂ FeS ₂ in the positive electrode active material. In addition, since the positive electrode layer 11 contains a carbon material as a conductive agent, the electronic conductivity can be increased.

Specifically, the positive electrode layer 11 includes, for example, Li ₂ FeS ₂ as a positive electrode active material and a mixture of Li ₂ S and P ₂ S ₅ that are ion conductive compounds as a solid electrolyte. The negative electrode layer 13 includes, for example, a carbon material such as spherical graphite as a negative electrode active material, and a mixture of Li ₂ S and P ₂ S ₅ that are ion conductive compounds as a solid electrolyte. The solid electrolyte layer 12 sandwiched between the positive electrode layer 11 and the negative electrode layer 13 includes, for example, a mixture of Li ₂ S and P ₂ S ₅ that are ion conductive compounds as the solid electrolyte. The positive electrode layer 11, the solid electrolyte layer 12, and the negative electrode layer 13 are each formed by compressing a raw material, or a solid-liquid mixture such as a slurry, a paste, or a colloid containing the raw material as a green sheet, a printing layer It is produced by molding into a film or the like. The solid electrolyte only needs to contain at least lithium and sulfur as constituent elements. As such a compound, in addition to a mixture of Li ₂ S and P ₂ S ₅ , for example, Li ₂ S and B ₂ S ₃ can be used. A mixture etc. can be mention | raise | lifted. In addition to lithium and sulfur as constituent elements, the solid electrolyte preferably further contains phosphorus. As such a compound, in addition to a mixture of Li ₂ S and P ₂ S ₅ , for example, Li ₇ P Examples include ₃ S ₁₁ , Li ₃ PS _4, and those in which some of these anions are oxygen-substituted. The composition ratio of the elements constituting the solid electrolyte is not limited to the above-described ratio. The positive electrode active material more preferably contains lithium, iron, and sulfur as constituent elements. Examples of such a compound include compounds such as Li _2.33 Fe _0.67 S _{2 in} addition to Li ₂ FeS _2. be able to. Further, other positive electrode active materials include compounds such as lithium titanium sulfide and lithium vanadium sulfide. The composition ratio of the elements constituting the positive electrode active material is not limited to the above-described ratio.

Note that the all-solid-state battery of the present invention may be used in the form in which the battery element shown in FIGS. 1 to 3 is inserted into a ceramic container, for example, as shown in FIGS. It may be used in a self-supporting form.

Next, specific examples of the present invention will be described. In addition, the Example shown below is an example and this invention is not limited to the following Example.

Hereinafter, Examples 1 to 5 and Comparative Examples 1 and 2 in which an all-solid battery is formed by forming an intervening layer will be described.

(Example 1)
An all-solid battery 10 having the cross-sectional structure shown in FIG.

<Production of carbon paste>
Acrylic resin (polyethyl methacrylate) was dissolved using terpineol (boiling point: 218 ° C.) as a solvent. A carbon paste was prepared by dispersing acetylene black powder as a carbon material in this solution. Acetylene black and acrylic resin were mixed at a weight ratio of 9: 1.

<Intermediate layer coating>
The carbon paste was coated on the surface of the current collector 15 made of a copper foil having a thickness of 10 μm using a coater and dried at a temperature of 120 ° C., thereby forming an intervening layer 14 having a thickness of 10 μm. .

<Preparation of solid electrolyte>
In an argon gas atmosphere, Li ₂ S powder and P ₂ S ₅ powder were weighed and mixed so as to have a molar ratio of 7: 3. This mixture was mechanically milled with a planetary ball mill at a temperature of 25 ° C. and a rotation speed of 370 rpm for 20 hours to obtain a white-yellow glass powder. The obtained glass powder was put in a closed glass container and heated at a temperature of 200 to 300 ° C. for 2 hours to obtain a sulfide glass ceramic. In this way, a sulfide solid electrolyte was produced.

<Preparation of solid electrolyte paste>
The acrylic resin was dissolved using terpineol as a solvent. The above-mentioned sulfide solid electrolyte was dispersed in this solution to prepare a solid electrolyte paste. The sulfide solid electrolyte and the acrylic resin were mixed at a weight ratio of 9: 1.

<Preparation of positive electrode mixture paste>
Li ₂ FeS ₂ powder as the positive electrode active material and the sulfide solid electrolyte described above were mixed using a rocking mill to prepare a positive electrode mixture. The positive electrode active material and the sulfide solid electrolyte were mixed at a weight ratio of 1: 1. The acrylic resin was dissolved using terpineol as a solvent. The positive electrode mixture was dispersed in this solution to prepare a positive electrode mixture paste. As for the mixing ratio, the positive electrode mixture and the acrylic resin were mixed at a weight ratio of 9: 1.

<Preparation of negative electrode mixture paste>
The graphite powder as the negative electrode active material and the above sulfide solid electrolyte were mixed using a rocking mill to prepare a negative electrode mixture. The negative electrode active material and the sulfide solid electrolyte were mixed at a weight ratio of 1: 1. The acrylic resin was dissolved using terpineol as a solvent. The negative electrode mixture was dispersed in this solution to prepare a negative electrode mixture paste. As for the mixing ratio, the negative electrode mixture and the acrylic resin were mixed at a weight ratio of 9: 1.

<Preparation of all-solid battery>
The negative electrode mixture paste was printed on the surface of the current collector 15 on which the intervening layer 14 was formed, using a screen printing plate having an opening pattern with an opening diameter of 7 mm. The obtained printed layer was dried at 60 ° C. in an atmosphere under reduced pressure for 1 hour to form a negative electrode layer 13 having a thickness of about 50 μm.

Next, the above solid electrolyte paste was printed on the negative electrode layer 13 using a screen printing plate having an opening pattern with an opening diameter of 9 mm. The obtained printed layer was dried at 60 ° C. in an atmosphere under reduced pressure for 1 hour to form a solid electrolyte layer 12 having a thickness of about 50 μm.

Then, the above positive electrode mixture paste was printed on the solid electrolyte layer 12 using a screen printing plate having an opening pattern with an opening diameter of 7 mm. The obtained printed layer was dried at 60 ° C. in an atmosphere under reduced pressure for 1 hour to form a positive electrode layer 11 having a thickness of about 50 μm. As described above, a laminate including the negative electrode layer 13, the solid electrolyte layer 12, and the positive electrode layer 11 was produced on the surface of the current collector 15 on which the intervening layer 14 was formed.

Next, as a cell for battery evaluation, a die having a diameter of 10 mm, in which a die portion is made of polyethylene terephthalate (PET) resin and upper and lower punches are made of stainless steel, was prepared. The laminate obtained above was punched into a cylindrical shape with a diameter of 9 mm and placed in the mold, and a pressure of 300 MPa was applied. In this way, an all-solid battery 10 was produced. The all solid state battery 10 was sealed.

(Example 2)
An all-solid battery 10 was produced in the same manner as in Example 1 except that the intervening layer 14 made of a stainless steel film having a thickness of 200 nm was formed on the surface of the current collector 15 made of copper foil using a sputtering apparatus. .

(Comparative Example 1)
An all-solid battery was produced in the same manner as in Example 1 except that the current collector 15 made of copper foil on which no intervening layer 14 was formed was used.

<Charge / discharge test>
The all solid state batteries of Example 1, Example 2, and Comparative Example 1 were charged at a temperature of 20 ° C. with a constant current of 6.4 μA / cm ² until the voltage reached 3V. Thereafter, the battery was discharged at a constant current of 6.4 μA / cm ² until the voltage reached 0V.

The all solid state battery 10 of Example 1 and Example 2 exhibited a discharge capacity of 160 mAh / g. On the other hand, the all-solid-state battery of Comparative Example 1 exhibited a discharge capacity of 80 mAh / g. In the all-solid-state battery of the comparative example 1, compared with the all-solid-state battery of Example 1 and Example 2, charge / discharge capacity was small, and when charging / discharging was repeated, the charge / discharge curve changed. From this, the all-solid-state battery of Comparative Example 1 deteriorates due to the reaction between the sulfide solid electrolyte and the copper foil of the current collector 15, and the all-solid-state battery 10 of Example 1 and Example 2 has the intervening layer 14. It is considered that deterioration did not occur by preventing the reaction between the sulfide solid electrolyte and the copper foil of the current collector 15.

(Example 3)
An all-solid battery 20 having the cross-sectional structure shown in FIG.

<Production of carbon paste>
A carbon paste was prepared by mixing acetylene black powder as a carbon material, polyvinylidene fluoride (PVDF) as a binder resin, and N-methyl-2-pyrrolidone (NMP) as a solvent.

<Intermediate layer coating>
The carbon paste was applied on both sides of a current collector 15 made of copper foil having a thickness of 15 μm using a coater, and dried at a temperature of 120 ° C., thereby forming an intervening layer 14 having a thickness of 5 μm. .

<Preparation of solid electrolyte>
A sulfide solid electrolyte was produced in the same manner as in Example 1 except that the molar ratio of Li ₂ S powder to P ₂ S ₅ powder was 8: 2.

<Preparation of positive electrode mixture>
Li ₂ FeS ₂ powder as the positive electrode active material and the sulfide solid electrolyte described above were mixed using a rocking mill to prepare a positive electrode mixture. The positive electrode active material and the sulfide solid electrolyte were mixed at a weight ratio of 1: 1.

<Preparation of negative electrode mixture>
Spherical graphite powder as a negative electrode active material and the above sulfide solid electrolyte were mixed using a rocking mill to prepare a negative electrode mixture. The negative electrode active material and the sulfide solid electrolyte were mixed at a weight ratio of 1: 1.

<Preparation of all-solid battery>
A current collector 15 in which the above-described intervening layer 14 is formed on both sides in a mold having a diameter of 10 mm, a negative electrode composite, a solid electrolyte, a positive electrode composite, and a current collector 15 in which the above intervening layer 14 is formed on both sides Then, the negative electrode composite material, the solid electrolyte, the positive electrode composite material, and the current collector 15 having the intervening layer 14 formed on both surfaces thereof were put in this order, and a pressure of 330 MPa was applied, whereby an all-solid battery 20 was produced. The all solid state battery 20 was sealed.

<Charge / discharge test>
The obtained all solid state battery 20 was charged at a temperature of 20 ° C. with a constant current of 6.4 μA / cm ² until the voltage reached 6V. Thereafter, the battery was discharged at a constant current of 6.4 μA / cm ² until the voltage reached 0V.

The all solid state battery 20 of Example 3 showed a discharge capacity of 150 mAh / g. It is considered that the all-solid-state battery 20 did not deteriorate because the intervening layer 14 prevented the reaction between the sulfide solid electrolyte and the copper foil of the current collector 15.

Example 4
An all-solid battery 20 having the cross-sectional structure shown in FIG.

In the same manner as in Example 1, a carbon paste is applied on one surface of a current collector 15 made of copper foil to form an intervening layer 14 made of a carbon material, and aluminum is formed on the other surface of the current collector 15. The all-solid-state battery 20 was produced in the same manner as in Example 3 except that the intervening layer 14 made of an aluminum film having a thickness of 100 nm was formed by vapor deposition. The current collector 15 having the intervening layer 14 formed on both surfaces is disposed so that the intervening layer 14 made of an aluminum film is in contact with the positive electrode layer 11 and the intervening layer 14 made of a carbon material is in contact with the negative electrode layer 13. .

The all solid state battery 20 of Example 4 showed a discharge capacity of 150 mAh / g. It is considered that the all-solid-state battery 20 did not deteriorate because the intervening layer 14 prevented the reaction between the sulfide solid electrolyte and the copper foil of the current collector 15.

(Comparative Example 2)
An all-solid battery was produced in the same manner as in Example 3 except that the current collector 15 made of copper foil on which no intervening layer 14 was formed was used.

The all solid state battery of Comparative Example 2 exhibited a discharge capacity of 74 mAh / g. The all-solid-state battery of Comparative Example 2 is considered to have a reduced discharge capacity because the sulfide solid electrolyte and the copper foil of the current collector 15 reacted and deteriorated.

(Example 5)
An all-solid battery 30 having the cross-sectional structure shown in FIG. 3 was produced.

A carbon paste was produced in the same manner as in Example 1. The carbon paste was screen-printed on the surface of the current collector 15 made of copper foil in the same manner as in Example 1 to form a circular intervening layer 141 having a diameter of 9 mm. Further, an intervening layer 142 made of a ring-shaped insulating layer having an outer diameter of 10 mm was formed on the outer peripheral portion of the intervening layer 141 by screen printing a pasty acrylic resin.

Next, in the same manner as in Example 1, the negative electrode layer 13, the solid electrolyte layer, the solid electrolyte paste, and the positive electrode mixture paste were used to form the negative electrode layer 13, the solid electrolyte layer on the surface of the current collector 15 on which the intervening layer 141 was formed. A columnar laminate having a diameter of 9 mm and 12 and the positive electrode layer 11 was produced.

On the surface of the positive electrode layer 11 of this laminate, a current collector 15 in which an intervening layer 14 similar to that of Example 1 was formed was placed, and the laminate was placed in a mold having a diameter of 10 mm, and a pressure of 300 MPa Was added. In this way, an all-solid battery 30 was produced. This all solid state battery 30 was sealed.

In the obtained all-solid-state battery 30, the electron conductive intervening layer 141 can prevent the reaction between the sulfide solid electrolyte and the current collector 15, and the electrically insulating intervening layer 142 allows the positive electrode side and the negative electrode An electrical short circuit on the side can be prevented.

It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above embodiments and examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims. .

According to the present invention, since the current collector does not react with the sulfide solid electrolyte, the applicable range of the current collector material can be expanded in the sulfide-based solid battery.

10, 20, 30: all solid state battery, 11: positive electrode layer, 12: solid electrolyte layer, 13: negative electrode layer, 14, 141, 142: intervening layer, 15: current collector.

Claims

At least one of the positive electrode layer and the negative electrode layer;
A solid electrolyte layer laminated on one surface of the electrode layer;
A current collector disposed on the surface on the other side opposite to the surface on one side of the electrode layer;
An intervening layer interposed between the electrode layer and the current collector,
The electrode layer includes an electrode active material and a sulfide solid electrolyte,
The intervening layer is an all-solid-state battery including a material that is less reactive with a sulfide solid electrolyte than copper.
The all-solid-state battery according to claim 1, wherein the intervening layer has conductivity for electrons and does not have conductivity for lithium ions.
The all-solid-state battery according to claim 1 or 2, wherein the intervening layer includes a carbon material.
The all-solid-state battery according to any one of claims 1 to 3, wherein the intervening layer contains a metal.
The all-solid-state battery according to claim 4, wherein the intervening layer contains stainless steel or aluminum as a metal.
Each of the first and second batteries includes a laminate in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are sequentially laminated.
The first battery is connected to the second battery;
The current collector is disposed between the positive electrode layer of the first battery and the negative electrode layer of the second battery, and the intervening layer includes a positive electrode layer of the first battery and the current collector. The all-solid-state battery according to any one of claims 1 to 5, wherein the all-solid-state battery is interposed between or at least one of the negative electrode layer of the second battery and the current collector.
The all-solid-state battery according to any one of claims 1 to 6, wherein a part of the intervening layer includes an electrical insulator.