WO2021075420A1

WO2021075420A1 - All-solid-state lithium secondary battery and production method for all-solid-state lithium secondary battery

Info

Publication number: WO2021075420A1
Application number: PCT/JP2020/038603
Authority: WO
Inventors: 佐藤　一; 甲相朴; 博幸上田
Original assignee: Ｄａｒｅジャパン株式会社
Priority date: 2019-10-15
Filing date: 2020-10-13
Publication date: 2021-04-22
Also published as: CN114026727A; JP7275300B2; JPWO2021075420A1; CN114026727B

Abstract

An all-solid-state lithium secondary battery (1) comprising: an oxide solid electrolyte layer (11) including oxide solid electrolyte particles (11a) having lithium ion conductivity; a positive electrode active material layer (13) arranged on one surface side of the oxide solid electrolyte layer (11); a negative electrode active material layer (16) arranged on the other surface side of the oxide solid electrolyte layer (11); and a solid electrolyte dispersion polymer layer arranged between the oxide solid electrolyte layer (11) and at least either the positive electrode active material layer (13) or the negative electrode active material layer (16) and having oxide solid electrolyte particles dispersed in a lithium ion conductive polymer material that has lithium ion conductivity. The positive electrode active material layer (13), the negative electrode active material layer (16), the solid electrolyte dispersion polymer layer, and the oxide solid electrolyte layer (11) are integrated.

Description

Manufacturing method of all-solid-state lithium secondary battery and all-solid-state lithium secondary battery

The present invention relates to an all-solid-state lithium secondary battery and a method for manufacturing an all-solid-state lithium secondary battery.

Lithium-ion batteries using non-aqueous electrolytes are widely used. However, lithium-ion batteries are limited in operating temperature because the electrolytic solution is flammable and there is a risk of ignition, and an organic solvent is used. Therefore, an all-solid-state lithium secondary battery using a polymer electrolyte has been developed. However, the polymer electrolyte has low ionic conductivity at low temperature, and the operating temperature range is narrower than that of the lithium ion battery using the non-aqueous electrolyte solution. Therefore, an all-solid-state lithium secondary battery using a sulfide-based solid electrolyte has been developed. However, the operating temperature range is limited because sulfides can react with water to generate hydrogen sulfide. Therefore, it is expected to develop an all-solid-state battery using an oxide-based solid electrolyte that can compensate for such drawbacks of polymer electrolytes and sulfide-based electrolytes.

For example, in Patent Document 1 below, a composite solid electrolyte layer having lithium ion conductive oxide particles and a lithium ion conductive amorphous portion inserted between the oxide particles is a positive electrode having a positive electrode active material. An all-solid-state lithium secondary battery sandwiched between a negative electrode having a negative electrode active material and a negative electrode is described.

Further, Patent Document 2 below describes a solid electrolyte for an all-solid-state lithium-ion secondary battery using an oxide solid electrolyte. In this solid electrolyte, an adhesive layer having lithium ion conductivity is provided on the surface of the solid electrolyte main body for the purpose of reducing the resistance at the interface between the solid electrolyte main body and the electrode.

Japanese Unexamined Patent Publication No. 2015-138471 JP-A-2017-069036

An all-solid-state lithium secondary battery using an oxide solid electrolyte as described in Patent Document 1 is easy to handle because it does not easily generate hydrogen sulfide by reacting with water, but the sulfide electrolyte is used. Compared to the all-solid-state lithium secondary battery, the internal resistance is high and the conductivity is low.

Further, the adhesive layer of the solid electrolyte described in Patent Document 2 is preferably as thin as possible because the ionic conductivity is an order of magnitude lower than that of the solid electrolyte body. However, if the adhesive layer is made thin, it may not be possible to fill the gap between the electrode and the solid electrolyte body, and there is a concern that the internal resistance will increase.

Therefore, in an all-solid-state lithium secondary battery using an oxide solid electrolyte that is easy to handle, it is desired that the internal resistance is reduced and a large current is achieved.

Therefore, an object of the present invention is to provide a method for manufacturing an all-solid-state lithium secondary battery and an all-solid-state lithium secondary battery that are easy to handle and can achieve a large current.

In order to solve the above problems, the all-solid lithium secondary battery of the present invention has an oxide solid electrolyte layer containing oxide solid electrolyte particles having lithium ion conductivity and one surface side of the oxide solid electrolyte layer. The positive electrode active material layer to be arranged, the negative electrode active material layer arranged on the other surface side of the oxide solid electrolyte layer, at least one of the positive electrode active material layer and the negative electrode active material layer, and the oxide solid electrolyte. The positive electrode active material layer comprises a solid electrolyte-dispersed polymer layer in which the oxide solid electrolyte particles are dispersed in a lithium ion conductive polymer material which is arranged between the layers and has lithium ion conductivity. The negative electrode active material layer, the solid electrolyte-dispersed polymer layer, and the oxide solid electrolyte layer are integrated.

Unlike the above sulfides, oxides do not easily generate gases that require careful handling, such as hydrogen sulfide, even when they react with water. Therefore, the all-solid-state lithium secondary battery of the present invention using the oxide solid electrolyte is easy to handle.

Further, the state in which the layers are integrated in the present specification means a state in which the layers cannot be peeled off and destruction occurs when the layers are forcibly peeled off. Therefore, in the all-solid-state lithium secondary battery of the present invention, the positive electrode active material layer, the negative electrode active material layer, the solid electrolyte-dispersed polymer layer, and the oxide solid electrolyte layer cannot be separated from each other. The resistors between the positive electrode active material layer, the negative electrode active material layer, the solid electrolyte-dispersed polymer layer, and the oxide solid electrolyte layer integrated in this way are not integrated and are simply arranged adjacent to each other. The resistance between the positive electrode active material layer, the negative electrode active material layer, the solid electrolyte-dispersed polymer layer, and the oxide solid electrolyte layer is reduced.

Further, in the all-solid-state lithium secondary battery of the present invention, the solid electrolyte-dispersed polymer layer comprises a lithium ion conductive polymer material having lithium ion conductivity and oxide solid electrolyte particles dispersed in the material. Including. In general, the oxide solid electrolyte particles have higher lithium ion conductivity than the lithium ion conductive polymer material. Therefore, the ion conductivity of the solid electrolyte dispersed polymer layer is the lithium ion conductivity as in the adhesive layer of Patent Document 2. Higher than a layer consisting only of a conductive polymer material. Therefore, the solid electrolyte-dispersed polymer layer of the present invention can be formed thicker than the layer made of only the lithium ion conductive polymer material such as the adhesive layer of Patent Document 2. Therefore, unlike the adhesive layer of Patent Document 2, it is not possible to fill the gap between the electrode and the solid electrolyte main body, so that it is possible to suppress an increase in internal resistance. Therefore, according to the all-solid-state lithium secondary battery of the present invention, the internal resistance can be reduced and a large current can be achieved.

Further, in the method for producing an all-solid lithium secondary battery of the present invention, a positive electrode active material layer is located on one surface side of an oxide solid electrolyte layer containing oxide solid electrolyte particles and having lithium ion conductivity, and an oxide is formed. The negative electrode active material layer is located on the other surface side of the solid electrolyte layer, and lithium having lithium ion conductivity between at least one of the positive electrode active material layer and the negative electrode active material layer and the oxide solid electrolyte layer. The oxide solid electrolyte layer, the positive electrode active material layer, the negative electrode active material layer, and the negative electrode active material layer so that the solid electrolyte dispersed polymer layer in which the oxide solid electrolyte particles are dispersed is located in the ion conductive polymer material. The step of arranging the solid electrolyte-dispersed polymer layer, the integration of the positive electrode active material layer, the negative electrode active material layer, the solid electrolyte-dispersed polymer layer, and the oxide solid electrolyte layer. It is characterized by having a process.

According to such a method for manufacturing an all-solid-state lithium secondary battery, an all-solid-state lithium secondary battery capable of achieving a large current with reduced internal resistance by using an oxide solid electrolyte that is easy to handle is manufactured. Can be done.

As described above, according to the present invention, there is provided a method for manufacturing an all-solid-state lithium secondary battery and an all-solid-state lithium secondary battery that are easy to handle and can achieve a large current.

It is a figure which shows the sectional view of the all-solid-state lithium secondary battery which concerns on embodiment of this invention. It is an enlarged view from the positive electrode active material layer to the oxide solid electrolyte layer in FIG. It is an enlarged view from the negative electrode active material layer to the oxide solid electrolyte layer in FIG. It is a flowchart of the manufacturing method of the all-solid-state lithium secondary battery which concerns on embodiment of this invention. It is a figure which shows the state of the preparation process. It is a figure which shows the state of the arrangement process. It is a figure which shows the state of the integration process. It is a call call plot which shows the measurement result of an Example.

Hereinafter, preferred embodiments of the method for manufacturing the all-solid-state lithium secondary battery and the all-solid-state lithium secondary battery according to the present invention will be described in detail with reference to the drawings. It should be noted that the embodiments illustrated below are for facilitating the understanding of the present invention, and are not for limiting the interpretation of the present invention. The present invention can be modified and improved without departing from the spirit of the present invention. In addition, for ease of understanding, some parts may be exaggerated in each figure.

FIG. 1 is a cross-sectional view of an all-solid-state lithium secondary battery according to an embodiment of the present invention. As shown in FIG. 1, the all-solid-state lithium secondary battery 1 of the present embodiment has a battery body 1b arranged in a packaging material 10. The battery element 1b includes an oxide solid electrolyte layer 11, a positive electrode side solid electrolyte dispersion polymer layer 12, a positive electrode active material layer 13, a positive electrode current collector layer 14, and a negative electrode side solid electrolyte dispersion polymer layer 15. The negative electrode active material layer 16 and the negative electrode current collector layer 17 are mainly provided.

<Oxide solid electrolyte layer>
FIG. 2 is an enlarged view from the positive electrode active material layer 13 to the oxide solid electrolyte layer 11 in FIG. As shown in FIG. 2, in the oxide solid electrolyte layer 11, the lithium ion conductive polymer material 11b has entered at least a part between the particles of the oxide solid electrolyte particles 11a, that is, the oxide solid electrolyte particles 11a. The structure is such that the lithium ion conductive polymer material 11b is arranged at least a part between the particles.

The oxide solid electrolyte constituting the oxide solid electrolyte particles 11a is not particularly limited as long as it is an oxide solid electrolyte having lithium ion conductivity, and for example, lithium aluminum titanium phosphate (LATP), lithium lanthanum zirconium oxide. (LLZO), lithium lanthanum titanium oxide (LLTO), aluminum-substituted germanium lithium phosphate (LAGP), and the like can be mentioned. In addition, silicon (Si) or germanium (Ge) may be added to LATP.

The average particle size of the oxide solid electrolyte particles 11a is, for example, 0.1 μm or more and 5 μm or less. In the present specification, the particle size refers to, for example, the average particle size measured by a 1090L type laser diffraction type particle size distribution measuring device manufactured by CILAS.

The lithium ion conductive polymer material 11b that penetrates between the particles of the oxide solid electrolyte particles 11a has lithium ion conductivity. Examples of such a lithium ion conductive polymer material 11b include those in which the polymer material has lithium ion conductivity. Examples of such a polymer material include polyethylene oxide (PEO), polyethylene glycol (PEG), polyvinylidene fluoride (PVDF) and the like. Further, as the lithium ion conductive polymer material 11b, a polymer containing a lithium salt can be mentioned. That is, the polymer does not have lithium ion conductivity, and the polymer contains a lithium salt as a supporting salt, so that the polymer has lithium ion conductivity. Examples of such lithium salts include lithium hexafluorophosphate (LiPF ₆ ), lithium borofluoride (LiBF ₄ ), lithium bis (oxalate) borate (LiBOB), and lithium bis (trifluoromethanesulfonyl) imide (LiTFSI). ), Lithium bis (fluorosulfonyl) imide (LiFSI) can be mentioned. In addition, a polymer having lithium ion conductivity such as PEO, PEG, and PVDF may be configured to contain a lithium salt. Further, it is preferable that the lithium ion conductive polymer is mixed with the lithium ion conductive oxide solid electrolyte particles. Examples of the oxide solid electrolyte particles in this case include particles similar to the oxide solid electrolyte particles that can be used for the oxide solid electrolyte particles 11a. In particular, lithium ion conductive oxides such as LATP and LLZO tend to have high lithium ion conductive polymer ion conductivity, so that the lithium ion conductivity can be further increased by mixing them.

As described above, the oxide solid electrolyte layer 11 of the present embodiment has a structure in which the lithium ion conductive polymer material 11b is inserted between the oxide solid electrolyte particles 11a, so that the oxide solid electrolyte layer 11 is an oxide solid. It is composed of only the electrolyte particles 11a, and the resistance can be made lower than that in the case where the lithium ion conductive polymer material 11b does not enter between the oxide solid electrolyte particles 11a. The oxide solid electrolyte layer 11 having such a structure may be referred to as a composite solid electrolyte layer.

<Positive electrode active material layer>
The positive electrode active material layer 13 of the present embodiment has a structure in which the lithium ion conductive polymer material 13b is inserted between the positive electrode active materials 13a and has lithium ion conductivity.

The material constituting the positive electrode active material 13a is not particularly limited as long as it contains lithium and can take in and release lithium ions, but for example, lithium manganate (LMO), lithium cobalt oxide (LCO), and the like. Lithium nickel oxide (LNO), ternary (NMC or NCA), lithium iron phosphate (LFP), vanadium phosphate oxide (LVP), cobalt manganese phosphate oxide (LCMP), and mixtures thereof. Can be mentioned. The ternary system referred to here refers to containing, for example, nickel, manganese, aluminum, or cobalt.

Examples of the lithium ion conductive polymer material 13b that penetrates between the positive electrode active materials 13a include materials similar to those that can be used for the lithium ion conductive polymer material 11b. In the present embodiment, the lithium ion conductive polymer material 13b that penetrates between the positive electrode active materials 13a and the lithium ion conductive polymer material 11b that penetrates between the particles of the oxide solid electrolyte particles 11a are the same material. However, they may be made of different materials.

Further, a conductive auxiliary agent such as acetylene black may be dispersed in the lithium ion conductive polymer material 13b of the positive electrode active material layer 13.

<Solid electrolyte dispersion polymer layer on the positive electrode side>
In the present embodiment, the solid electrolyte-dispersed polymer layer is formed by dispersing the oxide solid electrolyte particles 12a in the lithium ion conductive polymer material 12b between the positive electrode active material layer 13 and the oxide solid electrolyte layer 11. The positive electrode side solid electrolyte-dispersed polymer layer 12 is interposed. Examples of the lithium ion conductive polymer material 12b constituting the positive electrode side solid electrolyte dispersed polymer layer 12 include materials similar to the materials that can be used for the lithium ion conductive polymer material 11b of the oxide solid electrolyte layer 11. be able to.

Further, as the oxide solid electrolyte constituting the oxide solid electrolyte particles 12a of the positive electrode side solid electrolyte dispersion polymer layer 12, the oxide solid electrolyte that can be used for the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11 The same oxide solid electrolyte as above can be mentioned. From the viewpoint of reducing contact resistance, the oxide solid electrolyte particles 12a of the positive electrode side solid electrolyte dispersion polymer layer 12 and the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11 are made of the same oxide solid electrolyte. preferable. Further, the oxide solid electrolyte particles 12a of the positive electrode side solid electrolyte dispersion polymer layer 12 and the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11 may be made of different oxide solid electrolytes. In this case, for example, LAGP and LLZO are used as the oxide solid electrolyte constituting the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11, and the oxide solid electrolyte particles of the positive electrode side solid electrolyte dispersed polymer layer 12 are used. LATP is used as the oxide solid electrolyte constituting 12a. With such a combination, the reduction resistance of the oxide solid electrolyte can be improved.

Further, the particle size of the oxide solid electrolyte particles 12a of the positive electrode side solid electrolyte dispersion polymer layer 12 may be the same as the particle size of the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11. In this case, the average particle size of the oxide solid electrolyte particles 12a is, for example, 0.1 μm or more and 5 μm or less. However, the particle size of the oxide solid electrolyte particles 12a of the positive electrode side solid electrolyte-dispersed polymer layer 12 may be different from the particle size of the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11. For example, if the particle size of the oxide solid electrolyte particles 12a of the positive electrode side solid electrolyte dispersion polymer layer 12 is smaller than the particle size of the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11, the positive electrode side solid electrolyte dispersion height is high. It is preferable because the molecular layer 12 can be made thin and the resistance of the all-solid-state lithium secondary battery 1 can be reduced. Further, when the positive electrode side solid electrolyte-dispersed polymer layer 12 is formed by coating as described later, the oxide solid electrolyte particles 12a are formed between the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11 with lithium ion conductivity. It can be penetrated with the polymer material 12b. However, the particle size of the oxide solid electrolyte particles 12a of the positive electrode side solid electrolyte dispersion polymer layer 12 may be larger than the particle size of the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11.

The average thickness of the positive electrode side solid electrolyte-dispersed polymer layer 12 may be smaller than the particle size of the oxide solid electrolyte particles 12a. In this case, the positive electrode side solid electrolyte-dispersed polymer layer 12 becomes thicker at the portion where the oxide solid electrolyte particles 12a are located, and becomes thinner at the portion where the oxide solid electrolyte particles 12a are not located. Therefore, the oxide solid electrolyte particles 12a are likely to come into contact with the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11 and the positive electrode active material 13a.

Further, in the positive electrode side solid electrolyte-dispersed polymer layer 12, it is preferable that the volume ratio of the oxide solid electrolyte particles 12a is larger than the volume ratio of the lithium ion conductive polymer material 12b. By doing so, the resistance of the positive electrode side solid electrolyte-dispersed polymer layer 12 can be further reduced.

In the present embodiment, the oxide solid electrolyte layer 11 and the positive electrode side solid electrolyte dispersed polymer layer 12 are integrated, and the positive electrode active material layer 13 and the positive electrode side solid electrolyte dispersed polymer layer 12 are integrated. The oxide solid electrolyte layer 11 and the positive electrode active material layer 13 are integrated with each other via the positive electrode side solid electrolyte dispersed polymer layer 12. Therefore, when the oxide solid electrolyte layer 11 and the positive electrode active material layer 13 are peeled off, the cell structure is destroyed.

The lithium ion conductive polymer material 15b constituting the positive electrode side solid electrolyte dispersed polymer layer 12 and the lithium ion conductive polymer material 11b that penetrates between the oxide solid electrolyte particles 11a may be the same material. , The positive electrode side solid electrolyte dispersion polymer layer 12 and the oxide solid electrolyte layer 11 are preferable from the viewpoint of being able to increase the integrated strength. Further, in this case, it is also preferable from the viewpoint that the positive electrode side solid electrolyte-dispersed polymer layer 12 and the lithium ion conductive polymer material 11b that penetrates between the oxide solid electrolyte particles 11a can be formed at the same time by coating. However, even if the lithium ion conductive polymer material 12b of the positive electrode side solid electrolyte dispersed polymer layer 12 and the lithium ion conductive polymer material 11b that has entered between the oxide solid electrolyte particles 11a are the same material. , The positive electrode side solid electrolyte dispersion polymer layer 12 may be provided on the positive electrode side surface of the oxide solid electrolyte layer 11 in a state where the lithium ion conductive polymer material 11b is inserted between the oxide solid electrolyte particles 11a. Further, the lithium ion conductive polymer material constituting the positive electrode side solid electrolyte dispersed polymer layer 12 and the lithium ion conductive polymer material 11b that penetrates between the oxide solid electrolyte particles 11a may be different materials from each other. .. In this case, for example, PVDF is used as the lithium ion conductive polymer material constituting the positive electrode side solid electrolyte dispersed polymer layer 12, and the lithium ion conductive polymer material 11b that penetrates between the oxide solid electrolyte particles 11a is used. PEO is preferably used. With such a combination, the cell voltage can be increased by using PVDF, which is less likely to be decomposed than PEO on the high potential side. Therefore, it is possible to contribute to high potential and high energy of the all-solid-state lithium secondary battery 1.

Further, the positive electrode side is that the lithium ion conductive polymer material constituting the positive electrode side solid electrolyte-dispersed polymer layer 12 and the lithium ion conductive polymer material 13b that penetrates between the positive electrode active material 13a are the same material as each other. It is preferable from the viewpoint that the integrated strength between the solid electrolyte-dispersed polymer layer 12 and the positive electrode active material layer 13 can be increased. Further, the lithium ion conductive polymer material constituting the positive electrode side solid electrolyte-dispersed polymer layer 12 and the lithium ion conductive polymer material 13b that penetrates between the positive electrode active material 13a may be different materials from each other. In this case, for example, PEO is used as the lithium ion conductive polymer material 12b constituting the positive electrode side solid electrolyte-dispersed polymer layer 12, and PVDF is used as the lithium ion conductive polymer material 13b that penetrates between the positive electrode active materials 13a. Is preferably used. With such a combination, the cell voltage can be increased by using PVDF, which is less likely to be decomposed than PEO on the high potential side. Therefore, it is possible to contribute to high potential and high energy of the all-solid-state lithium secondary battery 1.

<Positive current collector layer>
The positive electrode current collector layer 14 is arranged on the surface side of the positive electrode active material layer 13 opposite to the oxide solid electrolyte layer 11 side, and is integrated with the positive electrode active material layer 13. The positive electrode current collector layer 14 is made of a conductive and non-ionic conductive material. Examples of such a material include a metal and a carbon sheet, and examples of such a metal include copper, aluminum, an iron-nickel alloy, and the like.

<Negative electrode active material layer>
FIG. 3 is an enlarged view from the negative electrode active material layer 16 to the oxide solid electrolyte layer 11 in FIG. The negative electrode active material layer 16 of the present embodiment has a structure in which the lithium ion conductive polymer material 16b is inserted between the negative electrode active materials 16a and has lithium ion conductivity.

The material constituting the negative electrode active material 16a is not particularly limited as long as it can take in and release lithium ions, and is, for example, easily graphitized carbon, non-graphitized carbon, LTO, LMO, Si, Li, and A mixture of these can be mentioned.

Examples of the lithium ion conductive polymer material 16b that penetrates between the negative electrode active materials 16a include materials that can be used for the lithium ion conductive polymer material 11b. In the present embodiment, the lithium ion conductive polymer material 16b that penetrates between the negative electrode active materials 16a and the lithium ion conductive polymer material 11b that penetrates between the particles of the oxide solid electrolyte particles 11a are the same material. However, they may be made of different materials. Further, the lithium ion conductive polymer material 16b that enters between the negative electrode active materials 16a and the lithium ion conductive polymer material 13b that enters between the positive electrode active materials 13a may be the same material or different materials. ..

Further, a conductive auxiliary agent such as acetylene black may be dispersed in the lithium ion conductive polymer material 16b of the negative electrode active material layer 16.

<Negative electrode side solid electrolyte dispersion polymer layer>
In the present embodiment, the solid electrolyte-dispersed polymer layer is formed by dispersing the oxide solid electrolyte particles 15a in the lithium ion conductive polymer material 15b between the negative electrode active material layer 16 and the oxide solid electrolyte layer 11. The negative electrode side solid electrolyte dispersion polymer layer 15 is interposed. Examples of the lithium ion conductive polymer material 15b constituting the negative electrode side solid electrolyte-dispersed polymer layer 15 include materials that can be used for the lithium ion conductive polymer material 11b.

Further, as the oxide solid electrolyte constituting the oxide solid electrolyte particles 15a of the negative electrode side solid electrolyte dispersion polymer layer 15, the oxide solid electrolyte that can be used for the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11 The same oxide solid electrolyte as above can be mentioned. From the viewpoint of reducing contact resistance, the oxide solid electrolyte particles 15a of the negative electrode side solid electrolyte dispersion polymer layer 15 and the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11 are made of the same oxide solid electrolyte. preferable. Further, the oxide solid electrolyte particles 15a of the negative electrode side solid electrolyte dispersion polymer layer 15 and the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11 may be made of different oxide solid electrolytes. In this case, for example, LATP is used as the oxide solid electrolyte constituting the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11, and the oxide solid electrolyte particles 15a of the negative electrode side solid electrolyte dispersion polymer layer 15 are used. LAGP and LLZO are used as the constituent oxide solid electrolytes. With such a combination, the reduction resistance at the negative electrode can be improved.

Further, the particle size of the oxide solid electrolyte particles 15a of the negative electrode side solid electrolyte dispersion polymer layer 15 may be the same as the particle size of the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11. However, the particle size of the oxide solid electrolyte particles 15a of the negative electrode side solid electrolyte dispersion polymer layer 15 may be different from the particle size of the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11. For example, if the particle size of the oxide solid electrolyte particles 15a of the negative electrode side solid electrolyte dispersion polymer layer 15 is smaller than the particle size of the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11, the negative electrode side solid electrolyte dispersion height is high. It is preferable because the molecular layer 15 can be made thin and the resistance of the all-solid-state lithium secondary battery 1 can be reduced. Further, when the negative electrode side solid electrolyte-dispersed polymer layer 15 is formed by coating as described later, the oxide solid electrolyte particles 15a are formed between the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11 with lithium ion conductivity. It can be incorporated with the polymer material 15b. However, the particle size of the oxide solid electrolyte particles 15a of the negative electrode side solid electrolyte dispersion polymer layer 15 may be larger than the particle size of the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11.

The average thickness of the negative electrode side solid electrolyte-dispersed polymer layer 15 may be smaller than the particle size of the oxide solid electrolyte particles 15a. In this case, the negative electrode side solid electrolyte-dispersed polymer layer 15 becomes thicker at the portion where the oxide solid electrolyte particles 15a are located, and becomes thinner at the portion where the oxide solid electrolyte particles 15a are not located. Therefore, the oxide solid electrolyte particles 15a are likely to come into contact with the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11 and the positive electrode active material 13a.

Further, in the negative electrode side solid electrolyte-dispersed polymer layer 15, it is preferable that the volume ratio of the oxide solid electrolyte particles 15a is larger than the volume ratio of the lithium ion conductive polymer material 15b. By doing so, the resistance of the negative electrode side solid electrolyte-dispersed polymer layer 15 can be further reduced.

In the present embodiment, the oxide solid electrolyte layer 11 and the negative electrode side solid electrolyte dispersed polymer layer 15 are integrated, and the negative electrode active material layer 16 and the negative electrode side solid electrolyte dispersed polymer layer 15 are integrated. The oxide solid electrolyte layer 11 and the negative electrode active material layer 16 are integrated with each other via the negative electrode side solid electrolyte dispersed polymer layer 15. Therefore, when the oxide solid electrolyte layer 11 and the negative electrode active material layer 16 are peeled off, destruction occurs.

The lithium ion conductive polymer material 15b constituting the negative electrode side solid electrolyte dispersed polymer layer 15 and the lithium ion conductive polymer material 11b that penetrates between the oxide solid electrolyte particles 11a may be the same material. , The negative electrode side solid electrolyte dispersion polymer layer 15 and the oxide solid electrolyte layer 11 are preferable from the viewpoint of being able to increase the integrated strength. Further, in this case, it is also preferable from the viewpoint that the negative electrode side solid electrolyte-dispersed polymer layer 15 and the lithium ion conductive polymer material 11b that penetrates between the oxide solid electrolyte particles 11a can be formed at the same time by coating. However, even if the lithium ion conductive polymer material 15b of the negative electrode side solid electrolyte dispersed polymer layer 15 and the lithium ion conductive polymer material 11b that has entered between the oxide solid electrolyte particles 11a are the same material. , The negative electrode side solid electrolyte dispersion polymer layer 15 may be provided on the negative electrode side surface of the oxide solid electrolyte layer 11 in a state where the lithium ion conductive polymer material 11b is inserted between the oxide solid electrolyte particles 11a. Further, the lithium ion conductive polymer material constituting the negative electrode side solid electrolyte dispersed polymer layer 15 and the lithium ion conductive polymer material 11b that penetrates between the oxide solid electrolyte particles 11a may be different materials from each other. .. In this case, for example, PVDF, SBR, acrylate and the like can be appropriately used as the lithium ion conductive polymer material constituting the negative electrode side solid electrolyte dispersion polymer layer 15, and the lithium ions entering between the oxide solid electrolyte particles 11a. It is preferable that PEO is used as the conductive polymer material 11b.

Further, the negative electrode side is that the lithium ion conductive polymer material constituting the negative electrode side solid electrolyte-dispersed polymer layer 15 and the lithium ion conductive polymer material 16b that penetrates between the negative electrode active material 16a are the same material as each other. It is preferable from the viewpoint that the integrated strength between the solid electrolyte-dispersed polymer layer 15 and the negative electrode active material layer 16 can be increased. Further, the lithium ion conductive polymer material constituting the negative electrode side solid electrolyte-dispersed polymer layer 15 and the lithium ion conductive polymer material 16b that penetrates between the negative electrode active material 16a may be different materials from each other. In this case, for example, PVDF is used as the lithium ion conductive polymer material constituting the negative electrode side solid electrolyte-dispersed polymer layer 15, and PEO and PEO are used as the lithium ion conductive polymer material 13b that penetrates between the negative electrode active materials 16a. A mixture of PVDFs is preferably used. With such a combination, the degree of adhesion between the negative electrode side solid electrolyte dispersion polymer layer 15 and the negative electrode active material layer 16 can be improved.

<Negative electrode current collector layer>
The negative electrode current collector layer 17 is arranged on the surface side of the negative electrode active material layer 16 opposite to the oxide solid electrolyte layer 11 side, and is integrated with the negative electrode active material layer 16. Examples of the material of the negative electrode current collector layer 17 include the same materials as those of the positive electrode current collector layer 14.

<Packaging material>
The packaging material 10 includes a positive electrode current collector layer 14, a positive electrode active material layer 13, a positive electrode side solid electrolyte dispersed polymer layer 12, an oxide solid electrolyte layer 11, a negative electrode side solid electrolyte dispersed polymer layer 15, and a negative electrode active material layer 16. , And a member that accommodates and seals the negative electrode current collector layer 17. A part of the positive electrode current collector layer 14 and the negative electrode current collector layer 17 is led out as electrodes to the outside of the packaging material 10.

The structure of the packaging material 10 is not particularly limited as long as external oxygen, moisture and the like are suppressed from entering the region surrounded by the packaging material 10 and do not conduct with the region, but for example, a metal such as aluminum. A foil laminated with a resin layer can be used.

As described above, the all-solid-state lithium secondary battery 1 of the present embodiment uses an oxide solid electrolyte, and unlike sulfide, it is difficult to generate a gas such as hydrogen sulfide that requires careful handling even if the oxide reacts with water. Therefore, it is easy to handle. Further, in the all-solid-state lithium secondary battery 1 of the present embodiment, the positive electrode active material layer 13, the negative electrode active material layer 16, the positive electrode side solid electrolyte dispersed polymer layer 12, and the negative electrode side solid electrolyte dispersed polymer layer 15 , The oxide solid electrolyte layer 11 is integrated so as not to be peeled off. The resistance between each of the layers thus integrated is less than the resistance between the layers that are not integrated and are simply arranged adjacent to each other.

Further, in the all-solid-state lithium secondary battery 1 of the present embodiment, the positive electrode-side solid electrolyte-dispersed polymer layer 12 interposed between the positive electrode current collector layer 14 and the oxide solid electrolyte layer 11 has high lithium ion conductivity. The oxide solid electrolyte particles 12a are dispersed in the molecular material 12b. Further, in the all-solid-state lithium secondary battery 1 of the present embodiment, the negative electrode side solid electrolyte-dispersed polymer layer 15 interposed between the negative electrode active material layer 16 and the oxide solid electrolyte layer 11 is a lithium ion conductive polymer. The oxide solid electrolyte particles 15a are dispersed in the material 15b. Generally, the oxide solid electrolyte particles have higher lithium ion conductivity than the lithium ion conductive polymer material, so that the ion conductivity of the positive electrode side solid electrolyte dispersed polymer layer 12 and the negative electrode side solid electrolyte dispersed polymer layer 15 is lithium. Higher than a layer consisting only of ionic conductive polymer material. Therefore, the positive electrode side solid electrolyte-dispersed polymer layer 12 and the negative electrode side solid electrolyte-dispersed polymer layer 15 of the present embodiment are between the positive electrode active material layer 13 and the oxide solid electrolyte layer 11 and the negative electrode active material layer 16. It can be formed thicker than the case where a layer made of only a lithium ion conductive polymer material is arranged between the oxide solid electrolyte layer 11 and the oxide solid electrolyte layer 11. Therefore, it is possible to suppress an increase in internal resistance due to the inability to fill the gap between the positive electrode active material layer 13 and the negative electrode active material layer 16 and the oxide solid electrolyte layer 11.

As described above, according to the all-solid-state lithium secondary battery 1 of the present embodiment, the internal resistance can be reduced and a large current can be achieved.

Next, a method for manufacturing the all-solid-state lithium secondary battery 1 of the present embodiment will be described.

FIG. 4 is a flowchart of a method for manufacturing the all-solid-state lithium secondary battery 1 according to the embodiment. As shown in FIG. 4, the method for manufacturing the all-solid-state lithium secondary battery 1 of the present embodiment includes a preparation step P1, an arrangement step P2, an integration step P3, and a sealing step P4.

<Preparation process P1>
This step is a step of mainly preparing the oxide solid electrolyte layer 11, the positive electrode active material layer 13, the positive electrode current collector layer 14, the negative electrode active material layer 16, and the negative electrode current collector layer 17. .. FIG. 5 is a diagram showing a state of the preparation process.

(Preparation of oxide solid electrolyte layer)
In the preparation of the oxide solid electrolyte layer 11, first, a green sheet in which the oxide solid electrolyte particles 11a are dispersed in the binder is prepared, and then the oxide solid electrolyte particles 11a are integrated with each other by firing. A porous sheet-like member to be the oxide solid electrolyte layer 11 can be obtained. Alternatively, even if the oxide solid electrolyte particles 11a are placed in a mold and molded into a sheet shape, a predetermined pressure is applied and fired to obtain a porous sheet-like member to be the oxide solid electrolyte layer 11. Good. Alternatively, the oxide solid electrolyte particles 11a may be dispersed in the binder and then molded into a sheet to harden the binder. The binder may be made of the lithium ion conductive polymer material 11b. Alternatively, the binder does not have to be made of the lithium ion conductive polymer material 11b, but in the present embodiment, the lithium ion conductive polymer material 11b is inserted between the oxide solid electrolyte particles 11a. In this case, the amount of the binder is such that voids are formed between the oxide solid electrolyte particles 11a. In this way, a sheet-like member containing the oxide solid electrolyte particles 11a is obtained.

Next, a dispersion liquid in which the oxide solid electrolyte particles are dispersed in the lithium ion conductive polymer material is applied to both surfaces of the sheet-like member containing the oxide solid electrolyte particles 11a and solidified. At this time, the lithium ion conductive polymer material coated between the oxide solid electrolyte particles 11a enters, and becomes the lithium ion conductive polymer material 11b arranged between the oxide solid electrolyte particles 11a. In this way, the oxide solid electrolyte layer 11 in which the lithium ion conductive polymer material 11b is inserted between the oxide solid electrolyte particles 11a shown in FIG. 5 is obtained. At this time, it is more preferable that the oxide solid electrolyte particles in the dispersion liquid enter between the oxide solid electrolyte particles 11a from the viewpoint of lowering the resistance. In this case, if the particle size of the oxide solid electrolyte particles in the dispersion liquid is smaller than the particle size of the oxide solid electrolyte particles 11a of the sheet-like member, the oxide solid electrolyte particles in the dispersion liquid are the oxide solid electrolyte particles 11a. It is preferable because it easily gets in between. As described above, the oxide solid electrolyte particles 11a are dispersed in the binder made of the lithium ion conductive polymer material 11b, and then molded into a sheet to harden the binder, whereby the sheet-like member is described. In this case, since the lithium ion conductive polymer material 11b has entered between the oxide solid electrolyte particles 11a before the coating, the lithium ion conductive polymer material 11b coated between the oxide solid electrolyte particles 11a by the coating. The polymer material does not have to enter.

Further, in the present embodiment, when the lithium ion conductive polymer material is applied to both sides of the sheet-like member made of the oxide solid electrolyte particles 11a, the lithium ion conductive polymer is applied on both sides of the sheet-like member. Apply a lithium-ion conductive polymer material to the extent that the material becomes a layer. As a result, the lithium ion conductive polymer material on one surface of the oxide solid electrolyte layer 11 solidifies to become the positive electrode side solid electrolyte dispersed polymer layer 12 shown in FIG. 5, and the other of the oxide solid electrolyte layer 11 The lithium ion conductive polymer material on the surface solidifies to form the negative electrode side solid electrolyte-dispersed polymer layer 15 shown in FIG.

(Preparation of positive electrode active material layer and positive electrode current collector)
In the preparation of the positive electrode active material layer and the positive electrode current collector, the positive electrode active material 13a and, if necessary, the conductive auxiliary agent are dispersed in the lithium ion conductive polymer material 13b, and the positive electrode current collector layer 14 is topped. Apply to and dry. In this way, the positive electrode active material layer 13 is provided on the positive electrode current collector layer 14.

(Preparation of negative electrode active material layer and negative electrode current collector)
In the preparation of the negative electrode active material layer and the negative electrode current collector, the negative electrode active material 16a and, if necessary, a conductive auxiliary agent are dispersed in the lithium ion conductive polymer material 16b, and the negative electrode current collector layer 17 is topped. Apply to and dry. In this way, the negative electrode active material layer 16 is provided on the negative electrode current collector layer 17.

<Placement process P2>
FIG. 6 is a diagram showing a state of this process. As shown in FIG. 6, after the preparation step P1, the positive electrode active material layer 13 and the positive electrode current collector layer 14 are laminated on one surface side of the oxide solid electrolyte layer 11, and the positive electrode active material layer 13 is an oxide solid. The electrolyte layer 11 is arranged so as to face the side. However, since the positive electrode side solid electrolyte dispersion polymer layer 12 is located on one surface of the oxide solid electrolyte layer 11 as described above, the positive electrode active material layer 13 is on the positive electrode side solid electrolyte dispersion polymer layer 12. Is placed in.

Further, a laminate of the negative electrode active material layer 16 and the negative electrode current collector layer 17 is arranged on the other surface side of the oxide solid electrolyte layer 11 so that the negative electrode active material layer 16 faces the oxide solid electrolyte layer 11 side. However, since the negative electrode side solid electrolyte dispersion polymer layer 15 is located on the other surface of the oxide solid electrolyte layer 11 as described above, the negative electrode active material layer 16 is on the negative electrode side solid electrolyte dispersion polymer layer 15. Is placed in.

Thus, as shown in FIG. 6, the oxide solid electrolyte layer 11, the positive electrode side solid electrolyte dispersed polymer layer 12, the positive electrode active material layer 13, the positive electrode current collector layer 14, the negative electrode side solid electrolyte dispersed polymer layer 15, and the negative electrode A battery element 1b in which the active material layer 16 and the negative electrode current collector layer 17 are laminated is obtained.

<Integration process P3>
After the arrangement step P2, the laminated oxide solid electrolyte layer 11, the positive electrode side solid electrolyte dispersed polymer layer 12, the positive electrode active material layer 13, the positive electrode current collector layer 14, the negative electrode side solid electrolyte dispersed polymer layer 15, and the negative electrode The active material layer 16 and the negative electrode current collector layer 17 are integrated. The oxide solid electrolyte layer 11, the positive electrode side solid electrolyte dispersion polymer layer 12, and the negative electrode side solid electrolyte dispersion polymer layer 15 are already integrated, and the positive electrode active material layer 13 and the positive electrode current collector layer 14 are integrated. The negative electrode active material layer 16 and the negative electrode current collector layer 17 are integrated. Therefore, in this step, the positive electrode side solid electrolyte-dispersed polymer layer 12 and the positive electrode active material layer 13 are integrated, and the negative electrode side solid electrolyte-dispersed polymer layer 15 and the negative electrode active material layer 16 are integrated.

FIG. 7 is a diagram showing this process. As shown in FIG. 7, in the present embodiment, integration is performed by a hot press. Specifically, the battery element 1b is sandwiched between a pair of heated

heat press molds

21 and 22. Then, each of the

heat press molds

21 and 22 is pressed in a heated state. At this time, the temperature of the

hot press molds

21 and 22 is higher than the temperature at which the lithium ion conductive polymer material constituting the positive electrode side solid electrolyte-dispersed polymer layer 12 and the negative electrode side solid electrolyte-dispersed polymer layer 15 softens. It is preferable to have. For example, if the lithium ion conductive polymer material is PEO, the temperature at which it softens is approximately 100 ° C., so that the temperature of the

heat press molds

21 and 22 is preferably higher than this temperature. Further, for example, when the lithium ion conductive polymer material is PEO as described above, setting the temperature to 130 ° C. or lower causes the lithium ion conductive polymer material to flow out due to the high fluidity. It is preferable from the viewpoint of suppressing. Further, for example, when the lithium ion conductive polymer material is PEO as described above, the temperature of the

hot press molds

21 and 22 is more preferably between 110 ° C. and 120 ° C. Further, the pressure for pressing the battery element 1b is, for example, preferably 1 MPa or more and 50 MPa or less from the viewpoint of being able to suppress the outflow of the lithium ion conductive polymer material while firmly integrating the respective layers.

Further, in this step, a part of the lithium ion conductive polymer material constituting the positive electrode side solid electrolyte dispersed polymer layer 12 may enter the positive electrode active material layer 13, and the negative electrode side solid electrolyte dispersed polymer layer 15 may be formed. A part of the constituent lithium ion conductive polymer material may enter the negative electrode active material layer 16.

In this way, the positive electrode side solid electrolyte-dispersed polymer layer 12 and the positive electrode active material layer 13 are integrated, and the negative electrode side solid electrolyte-dispersed polymer layer 15 and the negative electrode active material layer 16 are integrated. The battery element 1b in the material 10 is obtained.

<Seal step P4>
Next, the integrated battery body 1b is placed in the packaging material 10 and the packaging material 10 is sealed. It is preferable that heat fusion or the like is used for sealing.

In this way, the all-solid-state lithium secondary battery 1 shown in FIG. 1 is obtained.

As described above, according to the manufacturing method of the all-solid-state lithium secondary battery 1 of the present embodiment, the positive electrode active material layer 13, the negative electrode active material layer 16, and the oxide solid electrolyte layer 11 are integrated. Therefore, an oxide solid electrolyte that is easy to handle is used, and resistance between the positive electrode active material layer 13 and the oxide solid electrolyte layer 11 and between the negative electrode active material layer 16 and the oxide solid electrolyte layer 11 is increased. It is possible to manufacture the all-solid-state lithium secondary battery 1 which can reduce the current and achieve a large current.

Further, in the present embodiment, the integration step P3 is performed by thermocompression bonding. Therefore, for example, the integration step P3 can be performed more easily than when the integration step P3 is performed by using ultrasonic waves.

Although the present invention has been described above by taking embodiments as examples, the present invention is not limited thereto.

For example, in the above embodiment, the oxide solid electrolyte layer 11 is configured such that the lithium ion conductive polymer material 11b is inserted into at least a part between the particles of the oxide solid electrolyte particles 11a. However, in the present invention, as long as the oxide solid electrolyte layer 11 has lithium ion conductivity, the oxide solid electrolyte layer 11 does not have to have the lithium ion conductive polymer material 11b. However, from the viewpoint that the oxide solid electrolyte layer 11 maintains good lithium ion conductivity, it is preferable that the lithium ion conductive polymer material 11b is inserted into at least a part between the particles of the oxide solid electrolyte particles 11a.

Further, the lithium ion conductive polymer material 12b constituting the positive electrode side solid electrolyte dispersed polymer layer 12, the lithium ion conductive polymer material 15b constituting the negative electrode side solid electrolyte dispersed polymer layer 15, and the oxide solid electrolyte particles 11a. The material may be different from the lithium ion conductive polymer material 11b that penetrates between the particles of. In this case, in the preparation step P1, when the lithium ion conductive polymer material 11b that penetrates between the particles of the oxide solid electrolyte particles 11a is applied, the lithium ion conductive polymer material 11b is the oxide solid electrolyte particles 11a. The oxide solid electrolyte layer 11 is obtained by applying the coating so as not to form a layer on the sheet member. Then, a lithium ion conductive polymer material to be the positive electrode side solid electrolyte dispersion polymer layer 12 and the negative electrode side solid electrolyte dispersion polymer layer 15 may be coated on the obtained oxide solid electrolyte layer 11.

Further, the lithium ion conductive polymer material 13b does not have to enter between the positive electrode active material 13a of the positive electrode active material layer 13, and the lithium ion conductive polymer material between the negative electrode active material 16a of the negative electrode active material layer 16. 16b does not have to enter.

Further, in the above embodiment, the integration step P3 is performed by thermocompression bonding, but the integration step P3 may be performed by a method other than thermocompression bonding such as ultrasonic fusion.

Next, the polymer arranged between the particles of the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11 is a polymer having lithium ion conductivity, and lithium in the case where the lithium salt is dispersed in the polymer. The amount of salt was investigated.

(Example 1)
In order to prepare the battery body 1b, a laminate in which solid electrolyte dispersion polymer layers were provided on both sides of the oxide solid electrolyte layer 11 was prepared. In this preparation, first, a porous oxide solid electrolyte particle bonding layer to which the oxide solid electrolyte particles 11a were bonded was prepared. The oxide solid electrolyte particles consist of LLZO.

Next, a coating liquid made of a lithium ion conductive polymer material in which oxide solid electrolyte particles and lithium salts were dispersed was applied to both sides of the oxide solid electrolyte particle bonding layer. PEO was used as the lithium ion conductive polymer material, LiFSI was used as the lithium salt, and particles made of LLZO were used as the oxide solid electrolyte particles. The weight ratio of PEO and LiFSI was set to 1: 1. By this coating, at least the lithium ion conductive polymer material and the lithium salt are allowed to enter between the oxide solid electrolyte particles in the oxide solid electrolyte particle bonding layer, whereby the oxide solid electrolyte layer 11 shown in FIGS. 2 and 3 is formed. The positive electrode side solid electrolyte-dispersed polymer layer 12 was prepared from a layer made of a coating liquid formed on one surface of the oxide solid electrolyte layer 11 and formed on the other surface of the oxide solid electrolyte layer 11. A negative electrode side solid electrolyte-dispersed polymer layer 15 was prepared from a layer made of a coating liquid.

Further, a laminated body in which the positive electrode active material layer 13 is provided on one surface of the positive electrode current collector layer 14 was prepared. Specifically, an aluminum foil is used as the positive electrode current collector layer 14, and lithium nickelate (NCA), carbon black, acrylate, and carboxymethyl cellulose (CMC) are dispersed on one surface of the positive electrode current collector layer 14. The positive electrode active material layer 13 was obtained by applying and drying the solution to obtain the above-mentioned laminate.

Further, a laminated body in which the negative electrode active material layer 16 is provided on one surface of the negative electrode current collector layer 17 was prepared. Specifically, a copper foil is used as the negative electrode current collector layer 17, and graphitized carbon, styrene-butadiene block copolymer (SBR), and CMC are dispersed on one surface of the negative electrode current collector layer 17. The negative electrode active material layer 16 was obtained by applying and drying the solution to obtain the above-mentioned laminate.

Next, the above three laminated bodies were overlapped and integrated. Specifically, the positive electrode side solid electrolyte dispersion polymer layer 12 provided on one surface of the oxide solid electrolyte layer 11 and the positive electrode active material layer 13 provided on one surface of the positive electrode current collector layer 14. The negative electrode side solid electrolyte dispersion polymer layer 15 provided on the other surface of the oxide solid electrolyte layer 11 and the negative electrode active material layer 16 provided on one surface of the negative electrode current collector layer 17 are laminated. Overlaid. Next, the laminated bodies that were overlapped were integrated by thermocompression bonding.

In this way, the battery body 1b was obtained.

Next, an AC voltage was applied to the positive electrode current collector layer 14 and the negative electrode current collector layer 17 of the battery body 1b while sweeping the frequency, and impedance measurement was performed. The resulting call-call plot is shown in FIG. In FIG. 8, the horizontal axis represents the resistance component and the vertical axis represents the reactance component. As a result, the resistance of the battery body of Example 1 was about 50Ω.

(Example 2)
A battery element 1b was prepared in the same manner as in Example 1 except that the weight ratio of PEO and LiFSI was 4: 1. When PEO and LiFSI are used in a general all-solid-state lithium secondary battery other than the present invention, the weight ratio thereof is the same as that in this example. Impedance measurement was performed on the battery body 1b in the same manner as in Example 1. The resulting call-call plot is shown in FIG. As a result, the resistance of the battery element of the reference example was approximately 2000Ω.

Even the resistance of Example 2 is a sufficiently practical low resistance, but the resistance of Example 1 is about 1/40 of the resistance of Example 2. Therefore, the lithium ion height of the lithium ion conductive polymer material 11b that penetrates between the oxide solid electrolyte particles 11a of the oxide solid electrolyte layer 11, the positive electrode side solid electrolyte dispersed polymer layer 12, and the lithium ion conductive polymer material 13b. It was found that when the molecular material is PEO and LiFSI is dispersed in the lithium ion polymer material, the weight of LiFSI with respect to PEO is preferably 1 times or more.

If the weight of LiFSI with respect to PEO is more than twice, there is a concern about strength, so it is preferable that the weight of LiFSI with respect to PEO is twice or less.

As described above, according to the present invention, there is provided a method for manufacturing an all-solid-state lithium secondary battery and an all-solid-state lithium secondary battery that are easy to handle and can achieve a large current, and are used for automobile batteries and industrial equipment. It is expected to be used in the fields of batteries, batteries for consumer devices, etc.

Claims

An oxide solid electrolyte layer containing oxide solid electrolyte particles having lithium ion conductivity and
A positive electrode active material layer arranged on one surface side of the oxide solid electrolyte layer,
A negative electrode active material layer arranged on the other surface side of the oxide solid electrolyte layer,
The oxide solid electrolyte particles are arranged in at least one of the positive electrode active material layer and the negative electrode active material layer and the oxide solid electrolyte layer, and the oxide solid electrolyte particles are contained in a lithium ion conductive polymer material having lithium ion conductivity. The solid electrolyte dispersion polymer layer to be dispersed and
With
An all-solid-state lithium secondary battery characterized in that the positive electrode active material layer, the negative electrode active material layer, the solid electrolyte dispersed polymer layer, and the oxide solid electrolyte layer are integrated.
The first aspect of claim 1, wherein the lithium ion conductive polymer material of the solid electrolyte-dispersed polymer layer is contained in at least a part of the oxide solid electrolyte layer between the oxide solid electrolyte particles. All-solid-state lithium secondary battery.
The oxide solid electrolyte layer further comprises a lithium ion conductive polymer material that penetrates between the oxide solid electrolyte particles.
The lithium ion conductive polymer material that penetrates between the oxide solid electrolyte particles of the oxide solid electrolyte layer and the lithium ion conductive polymer material of the solid electrolyte dispersed polymer layer are the same material. The all-solid-state lithium secondary battery according to claim 1.
The solid electrolyte-dispersed polymer layer is arranged between the positive electrode active material layer and the negative electrode active material layer and the oxide solid electrolyte layer.
Lithium salts are dispersed in the lithium ion conductive polymer material of the oxide solid electrolyte layer and the lithium ion conductive polymer material of the solid electrolyte dispersed polymer layer, respectively.
The lithium ion conductive polymer material of the oxide solid electrolyte layer and the lithium ion conductive polymer material of the solid electrolyte dispersed polymer layer are polyethylene oxides.
The lithium salt is a lithium bis (fluorosulfonyl) imide and is
The all-solid-state lithium secondary battery according to claim 3, wherein the weight of the lithium salt with respect to the weight of the lithium ion conductive polymer material is 1 time or more and 2 times or less.
The oxide solid electrolyte layer further comprises a lithium ion conductive polymer material that penetrates between the oxide solid electrolyte particles.
The lithium ion conductive polymer material that penetrates between the oxide solid electrolyte particles of the oxide solid electrolyte layer and the lithium ion conductive polymer material of the solid electrolyte dispersed polymer layer are different materials. The all-solid-state lithium secondary battery according to claim 1, wherein the all-solid-state lithium secondary battery is characterized.
Any of claims 1 to 5, wherein the particle size of the oxide solid electrolyte particles in the solid electrolyte-dispersed polymer layer is smaller than the particle size of the oxide solid electrolyte particles in the oxide solid electrolyte layer. The all-solid-state lithium secondary battery according to item 1.
The positive electrode active material layer is located on one surface side of the oxide solid electrolyte layer containing oxide solid electrolyte particles and having lithium ion conductivity, and the negative electrode active material layer is located on the other surface side of the oxide solid electrolyte layer. The oxide solid electrolyte particles are dispersed in a lithium ion conductive polymer material having lithium ion conductivity between at least one of the positive electrode active material layer and the negative electrode active material layer and the oxide solid electrolyte layer. The arrangement step of arranging the oxide solid electrolyte layer, the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte dispersed polymer layer so that the solid electrolyte dispersed polymer layer is located.
An integration step of integrating the positive electrode active material layer, the negative electrode active material layer, the solid electrolyte-dispersed polymer layer, and the oxide solid electrolyte layer.
A method for manufacturing an all-solid-state lithium secondary battery.
The method for manufacturing an all-solid-state lithium secondary battery according to claim 7, wherein the integration step is performed by thermocompression bonding.