JP2022076417A - Composite solid electrolyte, all-solid-state battery, manufacturing method of composite solid electrolyte, and manufacturing method of all-solid-state battery - Google Patents

Abstract

To provide a composite solid electrolyte capable of suppressing a decrease in Coulomb efficiency in a charge/discharge cycle of an all-solid-state battery, and a manufacturing method thereof.SOLUTION: A composite solid electrolyte includes a sulfide solid electrolyte and an additive. The additive is a sulfur-based cyclic compound having an S=O bond, lithium nitrate, or a combination thereof. The content ratio of the additive is preferably 5 mass% or more and 20 mass% or less, and more preferably the sulfur-based cyclic compound is a cyclic sulfonic acid ester. A manufacturing method of the composite solid electrolyte includes mixing a sulfide solid electrolyte and an additive to prepare a composite solid electrolyte, and the additive is a sulfur-based cyclic compound having an S=O bond, lithium nitrate, or a combination thereof.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a composite solid electrolyte, an all-solid battery, a composite solid electrolyte, and a method for manufacturing an all-solid battery.

Non-aqueous electrolyte secondary batteries represented by lithium-ion non-aqueous electrolyte secondary batteries are widely used in personal computers, electronic devices such as communication terminals, automobiles, etc. due to their high energy density. The non-aqueous electrolyte secondary battery generally includes an electrode body having a pair of electrically isolated electrodes and a non-aqueous electrolyte interposed between the electrodes, and transfers ions between both electrodes. It is configured to charge and discharge with.

In recent years, for the purpose of improving the safety of a non-aqueous electrolyte secondary battery, an all-solid-state battery has been proposed in which a sulfide solid electrolyte or the like is used instead of a liquid electrolyte containing an organic solvent or the like as the non-aqueous electrolyte (). See Patent Document 1).

As the sulfide solid electrolyte, 70Li 2S ・ 30P ₂ S ₅ glass ceramics and 60Li ₂ S ・ 25P ₂ S ₅・_10Li 3N glass ceramics can ^{exhibit high ionic conductivity of 10 -3} _S / cm or more. It has been reported (Solid State Inics, 177, 2721 (2006), Solid State Inics, 304, 85 (2016)).

However, the pressure applied by the all-solid-state Li-Si half cell having a composition of Si: Cu: sulfide solid electrolyte (77.5 Li ₂ S / 22.5P ₂ S ₅ ) of 1: 1: 5 (m / m / m). When the relationship between the above and the cycle characteristics was evaluated, it was reported that the coulomb efficiency was low even when a high pressure (230 MPa) was applied so as not to cause isolation of silicon (Journal of the electrolyte solid state). , 160, 1, A77 (2013)). In addition, it has been clarified by first-principles calculation that the sulfide solid electrolyte has essentially low oxidation resistance and reduction resistance of the composite solid electrolyte (ACS Appl. Mater. Interfaces, 7, 23685 (2015). )).

Japanese Unexamined Patent Publication No. 2000-340257

In power storage elements such as non-aqueous electrolyte secondary batteries used in hybrid electric vehicles (hereinafter, also referred to as "HEV") and hybrid industrial machines (heavy machinery, construction machinery, etc.), the Coulomb efficiency in the charge / discharge cycle decreases. It is required to suppress the decrease in the Coulomb efficiency even in the all-solid-state battery.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a composite solid electrolyte capable of suppressing a decrease in Coulomb efficiency in the charge / discharge cycle of an all-solid-state battery.

One aspect of the present invention made to solve the above problems is a sulfur-based cyclic compound having an S = O bond, lithium nitrate, or a combination thereof, which comprises a sulfide solid electrolyte and an additive. A complex solid electrolyte.

Another aspect of the present invention comprises mixing a sulfide solid electrolyte with an additive to prepare a composite solid electrolyte, wherein the additive is a sulfur-based cyclic compound having an S = O bond, lithium nitrate or these. It is a method for producing a composite solid electrolyte which is a combination of the above.

The composite solid electrolyte according to one aspect of the present invention can suppress a decrease in Coulomb efficiency in the charge / discharge cycle of an all-solid-state battery.

FIG. 1 is a schematic cross-sectional view showing an all-solid-state battery according to an embodiment of the present invention. FIG. 2 is a graph showing the relationship between the number of charge / discharge cycles of Examples and Reference Examples and the Coulomb efficiency.

One aspect of the present invention is a composite solid electrolyte containing a sulfide solid electrolyte and an additive, wherein the additive is a sulfur-based cyclic compound having an S = O bond, lithium nitrate, or a combination thereof.

The present inventors consider that it is necessary to improve the reduction resistance of the sulfide solid electrolyte in order to improve the effect of suppressing the decrease in the Coulomb efficiency in the charge / discharge cycle of the all-solid-state battery. As a result, it was found that reduction resistance can be imparted to the sulfide solid electrolyte by using a specific additive. Then, it is considered that by combining a specific additive and a sulfide solid electrolyte, the reduction resistance of the solid electrolyte can be enhanced and the decrease in the Coulomb efficiency in the charge / discharge cycle of the all-solid-state battery can be suppressed. I arrived.

The composite solid electrolyte contains a sulfide solid electrolyte and an additive, and the additive is a sulfur-based cyclic compound having an S = O bond, lithium nitrate, or a combination thereof, whereby charging / discharging of an all-solid-state battery is performed. It is possible to suppress a decrease in the Coulomb efficiency in the cycle. The reason for this is not clear, but the following reasons are presumed. It is known that a general sulfide solid electrolyte is easily reduced and decomposed and exhibits a large reduction and decomposition capacity. The composite solid electrolyte is obtained by combining the sulfur-based cyclic compound having the S = O bond with the sulfide solid electrolyte and using it as the negative electrode or the solid electrolyte of the electrolyte layer interposed between the negative electrode and the positive electrode. = It is conceivable that the sulfur-based cyclic compound having an O bond opens by reduction to form electron-insulating Li _{2S and Li 2 O.} As a result, an ultrathin electron-insulating film is formed on the surface of the negative electrode or the electrolyte layer, so that continuous reduction decomposition of the sulfide solid electrolyte is suppressed, and it is presumed that the Coulomb efficiency is improved. Since the reduction decomposition potential of the non-aqueous electrolytic solution used in a general lithium ion non-aqueous electrolytic solution secondary battery is less than 1.0 V (for example, ethylene carbonate is about 0.6 V), for example, the lithium ion non-aqueous electrolytic solution 2 When 1,3-propensulton, which is a sulfur-based cyclic compound having an S = O bond, is used as an additive in the next battery, the above 1,3-propensulton precedes the other constituents of the non-aqueous electrolyte solution. It is presumed that the decomposition of the non-aqueous electrolytic solution can be suppressed by decomposing and forming a film on the surface of the negative electrode. On the other hand, since the sulfide solid electrolyte has a higher reduction decomposition potential than 1,3-propensulton, in the composite solid electrolyte, the lithium ion non-aqueous electrolyte solution is the non-aqueous electrolyte solution of the secondary battery. It is thought that the effect can be obtained by a mechanism different from that.
On the other hand, in the composite solid electrolyte, lithium nitrate, which has a higher reduction potential than the sulfide solid electrolyte, is combined with the sulfide solid electrolyte and used as the negative electrode or the solid electrolyte of the electrolyte layer interposed between the negative electrode and the positive electrode. , Lithium nitrate is reduced and decomposed before the sulfide solid electrolyte. As a result, a thin electronically insulating film (SEI: Solid Electrolyte Interphase) is formed on the surface of the negative electrode by reduction decomposition of lithium nitrate.
Therefore, the composite solid electrolyte can suppress the continuous reduction and decomposition of the solid electrolyte that occurs on the negative electrode side, and can suppress the decrease in the Coulomb efficiency in the charge / discharge cycle. Here, "SEI" is a film formed on the surface of the negative electrode due to the reduction and decomposition of the electrolyte during the first charge, and functions as a non-working state in which the subsequent reduction and decomposition of the electrolyte is suppressed, and at the same time, the negative electrode is subjected to lithium ion conduction. It provides a field for lithium ion deinsertion at the interface between the and the electrolyte.

The content ratio of the additive in the composite solid electrolyte is preferably 5% by mass or more and 20% by mass or less. When the content ratio of the additive is 5% by mass or more and 20% by mass or less, the reduction resistance of the composite solid electrolyte is further improved, and the effect of suppressing the decrease in the Coulomb efficiency in the charge / discharge cycle of the all-solid-state battery is further improved. Can be enhanced.

The sulfur-based cyclic compound is preferably a cyclic sulfonic acid ester. When the sulfur-based cyclic compound is a cyclic sulfonic acid ester, the reduction resistance of the composite solid electrolyte can be further improved, and the effect of suppressing a decrease in Coulomb efficiency in the charge / discharge cycle of the all-solid-state battery can be further enhanced.

The all-solid-state battery according to another aspect of the present invention includes a negative electrode, a positive electrode, and an electrolyte layer interposed between the negative electrode and the positive electrode, and the negative electrode, the electrolyte layer, or a combination thereof is the composite solid. Contains electrolytes. In the all-solid-state battery, since the negative electrode, the electrolyte layer, or a combination thereof contains the composite solid electrolyte, the additive is reduced and decomposed before the sulfide solid electrolyte. As a result, an electron-insulating film is formed on the negative electrode side by the reduction decomposition of the additive, and the continuous reduction decomposition of the sulfide solid electrolyte generated on the negative electrode side is suppressed, and the Coulomb efficiency in the charge / discharge cycle is reduced. Excellent effect of suppressing the decrease.

The method for producing a composite solid electrolyte according to another aspect of the present invention comprises mixing a sulfide solid electrolyte and an additive to prepare a composite solid electrolyte, in which the additive is sulfur having an S = O bond. Cyclic compounds, lithium nitrate or a combination thereof.

The method for producing the composite solid electrolyte comprises mixing a sulfide solid electrolyte and an additive to prepare a composite solid electrolyte, wherein the additive is a sulfur-based cyclic compound having an S = O bond, lithium nitrate, or these. By the combination of the above, it is possible to produce a composite solid electrolyte having reduction resistance and having an excellent effect of suppressing a decrease in Coulomb efficiency in the charge / discharge cycle of the all-solid-state battery.

In the method for producing the composite solid electrolyte, it is preferable that the content ratio of the additive in the composite solid electrolyte is 5% by mass or more and 20% by mass or less. When the content ratio of the above additive is 5% by mass or more and 20% by mass or less, the reduction resistance is further improved, and the composite solid electrolyte having a more excellent effect of suppressing the decrease in the Coulomb efficiency in the charge / discharge cycle of the all-solid-state battery is obtained. Can be manufactured.

In the method for manufacturing an all-solid-state battery according to another aspect of the present invention, at least one of a negative electrode and an electrolyte layer is manufactured using the composite solid electrolyte or the composite solid electrolyte obtained by the method for manufacturing the composite solid electrolyte. Be prepared to do. Since the method for manufacturing the all-solid-state battery comprises using the composite solid electrolyte or the composite solid electrolyte obtained by the method for manufacturing the composite solid electrolyte to prepare at least one of the negative electrode and the electrolyte layer, charging and discharging are provided. It is possible to manufacture an all-solid-state battery having an excellent effect of suppressing a decrease in Coulomb efficiency in a cycle.

Hereinafter, embodiments of a composite solid electrolyte, an all-solid-state battery, a method for manufacturing a composite solid electrolyte, and a method for manufacturing an all-solid-state battery according to the present invention will be described in detail.

<Composite solid electrolyte>
The composite solid electrolyte contains a sulfide solid electrolyte and an additive, and the additive is a sulfur-based cyclic compound having an S = O bond, lithium nitrate, or a combination thereof. The composite solid electrolyte contains a sulfide solid electrolyte and an additive, and the additive is a sulfur-based cyclic compound having an S = O bond, lithium nitrate, or a combination thereof, and thus has excellent reduction resistance. It is possible to suppress a decrease in sulfur efficiency in the charge / discharge cycle of an all-solid-state battery. The composite solid electrolyte can be used in any application that requires ionic conductivity. Above all, the composite solid electrolyte is preferably used for a lithium all-solid-state battery.

The sulfide solid electrolyte preferably has high lithium ion conductivity, for example, Li ₂ SP ₂ S ₅ , Li ₂ SP ₂ S ₅ -LiI, Li ₂ SP ₂ S ₅ -LiCl, and the like. Li ₂ SP 2 S 5-LiBr, Li ₂ SP ₂ S ₅ -Li ₂ O, Li ₂ SP ₂ S _{5 -Li 2} O-LiI, Li ₂ SP ₂ S _{5 -} Li ₃ N, Li ₂ S-SiS ₂ , Li ₂ S-SiS ₂ -LiI, Li ₂ S-SiS ₂ -LiBr, Li ₂ S-SiS ₂ -LiCl, Li ₂ S-SiS ₂ -B ₂ S ₃ -LiI, Li ₂ S-SiS ₂ -P ₂ S ₅ -LiI, Li ₂ SB ₂ S ₃ , Li ₂ SP ₂ S ₅ -Z _m S _2n (where m and n are positive numbers, Z is It is one of Ge, Zn, and Ga.), Li ₂ S-GeS ₂ , Li ₂ S-SiS ₂ -Li ₃ PO ₄ , Li ₂ S-SiS ₂ -Li _x MO _y (where x, y are Positive numbers, M is any of P, Si, Ge, B, Al, Ga, In), Li ₁₀ GeP ₂ S ₁₂ and the like. Among these, Li ₂ SP ₂ S ₅ is preferable, and xLi ₂ S · (100-x) P ₂ S ₅ (70 ≦ x ≦ 80) is more preferable from the viewpoint of good lithium ion conductivity.

The additive is a sulfur-based cyclic compound having an S = O bond, lithium nitrate, or a combination thereof. By using the sulfur-based cyclic compound having the S = O bond as an additive in the composite solid electrolyte, the sulfur-based cyclic compound is ring-opened by reduction to obtain electron-insulating Li _{2S and Li 2 O.} It is possible to form. As a result, it is considered that an ultrathin electronically insulating film is formed on the surface of the negative electrode or the electrolyte layer. On the other hand, in the composite solid electrolyte, lithium nitrate is reduced and decomposed before the sulfide solid electrolyte by using lithium nitrate, which has a higher reduction potential than the sulfide solid electrolyte, as an additive. As a result, SEI is formed on the surface of the negative electrode or the electrolyte layer. As described above, the composite solid electrolyte can suppress the continuous reduction and decomposition of the sulfide solid electrolyte generated on the negative electrode side, and can suppress the decrease in the Coulomb efficiency in the charge / discharge cycle.

Examples of the sulfur-based cyclic compound having an S = O bond include a sultone-based compound, a cyclic sulfate compound, a cyclic sulfate compound, a sulfolane-based compound, a cyclic disulfonate-based compound, and a sulfobenzoic acid anhydride.

Examples of the sultone compound include 1,3-propane sultone, 1,3-propene sultone, 2,4-butane sultone, and 1,4-butane sultone.

Examples of the cyclic sulphite compound include ethylene sulphite, 1,2-propylene glycol sulphite, trimethylene sulphite, and 1,3-butylene glycol sulphite.

Examples of the sulfolane compound include sulfolane, 3-sulfolene, 1,1-dioxothiophene, 3-methylsulfone, 3-methyl-2,5-dihydrothiophene-1,1-dioxide, and 3-sulfolen-3-carboxylic acid. Examples include methyl.

Examples of the cyclic disulfonate-based compound include methylene-methanedisulfonic acid ester and ethylene-methanedisulfonic acid ester.

The sulfur-based cyclic compound is preferably a cyclic sulfonic acid ester. When the sulfur-based cyclic compound is a cyclic sulfonic acid ester, the reduction resistance of the composite solid electrolyte can be further improved, and the effect of suppressing a decrease in Coulomb efficiency in the charge / discharge cycle of the all-solid-state battery can be further enhanced.

As the lower limit of the content ratio of the additive in the composite solid electrolyte, 1% by mass is preferable, 3% by mass is more preferable, and 5% by mass is further preferable. On the other hand, as the upper limit of the content ratio of the additive, 20% by mass is preferable, 18% by mass is more preferable, and 15% by mass is further preferable. When the content ratio of the additive is in the above range, the reduction resistance of the composite solid electrolyte is further improved, and the effect of suppressing the decrease in the Coulomb efficiency in the charge / discharge cycle of the all-solid-state battery can be further enhanced. The preferable range of the content ratio of the additive in the composite solid electrolyte is higher than the content ratio of the additive in the lithium ion non-aqueous electrolyte secondary battery. This is because, in a lithium ion non-aqueous electrolyte secondary battery, even if the additive is consumed at the negative electrode-non-aqueous electrolyte interface, the additive is supplied to the negative electrode-non-aqueous electrolyte interface by diffusion from the bulk. The effect can be obtained even in the range where the content ratio of the additive is small. On the other hand, in the all-solid-state battery, since the particulate additive is dispersed in the solid electrolyte, it is difficult for the state like the lithium ion non-aqueous electrolyte secondary battery to occur, and as a result, the additive is added. It is presumed that the effect is difficult to obtain in the range where the content ratio of the above is small as in the case of the lithium ion non-aqueous electrolyte secondary battery.

The lower limit of the ionic conductivity of the composite solid electrolyte at 25 ° C. is preferably 1.0 × ^10-5 S / cm, more preferably 5.0 × ^10-5 S / cm, and 1.0 × 10 ^-4 . Is even more preferable. When the ionic conductivity of the composite solid electrolyte at 25 ° C. is within the above range, the high rate charge / discharge performance of the all-solid-state battery can be improved.

The composite solid electrolyte can be suitably used as a solid electrolyte for a negative electrode and a solid electrolyte for an electrolyte layer of an all-solid-state battery.

<All-solid-state battery>
The all-solid-state battery includes a negative electrode, a positive electrode, and an electrolyte layer interposed between the negative electrode and the positive electrode. FIG. 1 is a schematic cross-sectional view showing an all-solid-state battery 10 according to an embodiment of the present invention. In the all-solid-state battery 10 which is a secondary battery, the negative electrode 1 and the positive electrode 2 are arranged via the solid electrolyte layer 3. The negative electrode 1 has a negative electrode base material 4 and a negative electrode mixture layer 5, and the negative electrode base material 4 is the outermost layer of the negative electrode 1. The positive electrode 2 has a positive electrode base material 7 and a positive electrode mixture layer 6, and the positive electrode base material 7 is the outermost layer of the positive electrode 2. In the all-solid-state battery 10 shown in FIG. 1, the positive electrode mixture layer 6, the solid electrolyte layer 3, the negative electrode mixture layer 5, and the negative electrode base material 4 are laminated in this order on the positive electrode base material 7.

In the all-solid-state battery, the negative electrode 1, the solid electrolyte layer 3, or a combination thereof contains the composite solid electrolyte. In the all-solid-state battery, since the negative electrode 1, the solid electrolyte layer 3 or a combination thereof contain the composite solid electrolyte, the effect of suppressing the decrease in Coulomb efficiency in the charge / discharge cycle is excellent.

The all-solid-state battery may be used in combination with other solid electrolytes other than the composite solid electrolyte. The other solid electrolyte may be a sulfide solid electrolyte other than the composite solid electrolyte, or may be an oxide-based solid electrolyte, a dry polymer electrolyte, a gel polymer electrolyte, or a pseudo-solid electrolyte.

As the sulfide solid electrolyte other than the composite solid electrolyte, the above-mentioned sulfide solid electrolyte can be used.

[Negative electrode]
The negative electrode 1 includes a negative electrode base material 4 and a negative electrode mixture layer 5 laminated on the surface of the negative electrode base material 4. The negative electrode 1 may have an intermediate layer (not shown) between the negative electrode base material 4 and the negative electrode mixture layer 5.

(Negative electrode base material)
The negative electrode base material 4 is a layer having conductivity. The material of the negative electrode base material 4 is not limited as long as it is a conductor. For example, alloys including copper, aluminum, titanium, nickel, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth, antimony, gold, silver, iron, platinum, chromium, tin, indium and one or more of these, as well as stainless alloys. One or more metals selected from the group consisting of can be mentioned.

The lower limit of the average thickness of the negative electrode base material 4 is preferably 3 μm, more preferably 5 μm, and even more preferably 8 μm. The upper limit of the average thickness of the negative electrode base material 4 is preferably 200 μm, more preferably 100 μm, and even more preferably 50 μm. By setting the average thickness of the negative electrode base material 4 to be equal to or greater than the above lower limit, the strength of the negative electrode base material 4 can be sufficiently increased, so that the negative electrode 1 can be formed satisfactorily. By setting the average thickness of the negative electrode base material 4 to be equal to or less than the above upper limit, it is possible to sufficiently secure the volumes of other components.

(Negative electrode mixture layer)
The negative electrode mixture layer 5 can be formed from a so-called negative electrode mixture containing a negative electrode active material. The negative electrode mixture may contain a mixture or a complex containing a negative electrode active material and a solid electrolyte. The solid electrolyte may be the composite solid electrolyte. Further, the negative electrode mixture may contain the composite solid electrolyte that does not form a mixture or a complex with the negative electrode active material. The negative electrode mixture contains optional components such as a solid electrolyte, a conductive agent, a binder, and a filler other than the composite solid electrolyte, if necessary.

<Negative electrode active material>
The negative electrode active material can be appropriately selected from known negative electrode active materials. As the negative electrode active material for a lithium ion secondary battery, a material capable of storing and releasing lithium ions is usually used. Examples of the negative electrode active material include metal Li; metal or semi-metal such as Si and Sn; metal oxide or semi-metal oxide such as Si oxide, Ti oxide and Sn oxide; Li ₄ Ti ₅ O ₁₂ ; Titanium-containing oxides such as LiTIO _{2 and} TiNb _{2O 7} ; polyphosphate compounds; silicon carbide; carbon materials such as graphite (graphitite) and non-graphitizable carbon (graphitizable carbon or non-graphitizable carbon). Be done. Among these materials, graphite and non-graphitic carbon are preferable. In the negative electrode active material layer, one of these materials may be used alone, or two or more thereof may be mixed and used.

“Graphite” refers to a carbon material having an average lattice spacing (d ₀₀₂ ) of (002) planes determined by X-ray diffraction before charging / discharging or in a discharged state of 0.33 nm or more and less than 0.34 nm. Examples of graphite include natural graphite and artificial graphite. Artificial graphite is preferable from the viewpoint that a material having stable physical properties can be obtained.

"Non-graphitic carbon" refers to a carbon material having an average lattice spacing (d ₀₀₂ ) of the (002) plane determined by X-ray diffraction before charging / discharging or in a discharged state of 0.34 nm or more and 0.42 nm or less. say. Examples of non-graphitizable carbon include non-graphitizable carbon and easily graphitizable carbon. Examples of the non-planar carbon include a resin-derived material, a petroleum pitch or a petroleum pitch-derived material, a petroleum coke or a petroleum coke-derived material, a plant-derived material, an alcohol-derived material, and the like.

Here, the "discharged state" means a state in which the open circuit voltage is 0.7 V or more in a single-pole battery using a negative electrode containing a carbon material as a negative electrode active material as a working electrode and metal Li as a counter electrode. Since the potential of the metal Li counter electrode in the open circuit state is substantially equal to the redox potential of Li, the open circuit voltage in the single pole battery is substantially equal to the potential of the negative electrode containing the carbon material with respect to the redox potential of Li. .. That is, the fact that the open circuit voltage in the single-pole battery is 0.7 V or more means that the carbon material, which is the negative electrode active material, sufficiently releases lithium ions that can be occluded and discharged by charging and discharging. ..

The “non-graphitizable carbon” refers to a carbon material having d ₀₀₂ of 0.36 nm or more and 0.42 nm or less.

The “graphitizable carbon” refers to a carbon material having d ₀₀₂ of 0.34 nm or more and less than 0.36 nm.

The lower limit of the content of the negative electrode active material in the negative electrode mixture is preferably 10% by mass, more preferably 15% by mass. The upper limit of the content of the negative electrode active material is preferably 60% by mass, more preferably 70% by mass, further preferably 80% by mass, further preferably 90% by mass, and particularly preferably 95% by mass. By setting the content of the negative electrode active material in the above range, the electric capacity of the all-solid-state battery can be increased.

<Mixture or complex>
The above-mentioned mixture is a mixture produced by mixing a negative electrode active material and the composite solid electrolyte by mechanical milling or the like. For example, the mixture of the negative electrode active material and the composite solid electrolyte can be obtained by mixing the negative electrode active material in the form of particles and the composite solid electrolyte in the form of particles.
Examples of the composite include a composite having a chemical or physical bond between the negative electrode active material and the composite solid electrolyte, a composite obtained by mechanically complexing the negative electrode active material and the composite solid electrolyte, and the like. .. The composite is one in which the negative electrode active material and the composite solid electrolyte are present in one particle, and for example, the negative electrode active material and the composite solid electrolyte forming an aggregated state, and the negative electrode active material. Examples thereof include those in which the composite solid electrolyte-containing film is formed on at least a part of the surface.
The mixture or complex may contain a solid electrolyte other than the composite solid electrolyte.
By forming a mixture or composite of the negative electrode active material and the composite solid electrolyte contained in the negative electrode mixture, the reduction resistance of the composite solid electrolyte can be improved while maintaining high ionic conductivity, so that the charge / discharge cycle can be performed. The effect of suppressing the decrease in the Coulomb efficiency is excellent.

When the negative electrode mixture contains the composite solid electrolyte, the lower limit of the content of the composite solid electrolyte in the negative electrode mixture may be 5% by mass, preferably 10% by mass. The upper limit of the content of the composite solid electrolyte in the negative electrode mixture is preferably 90% by mass, more preferably 85% by mass, further preferably 80% by mass, and particularly preferably 75% by mass. By setting the content of the composite solid electrolyte in the negative electrode mixture within the above range, it is possible to further improve the effect of suppressing the decrease in Coulomb efficiency in the charge / discharge cycle of the all-solid-state battery when the negative electrode contains the composite solid electrolyte. ..

The negative electrode mixture may contain a solid electrolyte other than the composite solid electrolyte. When the negative electrode mixture contains a solid electrolyte other than the composite solid electrolyte, the lower limit of the total content of the solid electrolyte in the negative electrode mixture may be 5% by mass, preferably 10% by mass. The upper limit of the total content of the solid electrolyte in the negative electrode mixture is preferably 90% by mass, more preferably 85% by mass, further preferably 80% by mass, and particularly preferably 75% by mass. By setting the total content of the solid electrolyte in the above range, the electric capacity of the all-solid-state battery can be increased.

<Any other ingredient>
The conductive agent is not particularly limited. Examples of such a conductive agent include natural or artificial graphite, carbon black such as furnace black, acetylene black, and Ketjen black, metal, and conductive ceramics. Examples of the shape of the conductive agent include powder and fibrous. The content of the conductive agent in the negative electrode mixture can be, for example, 0.5% by mass or more and 30% by mass or less. The negative electrode mixture does not have to contain a conductive agent.

The binder is not particularly limited. Examples of the binder include fluororesins (polytetrafluoroethylene (PTFE), polyfluorovinylidene (PVDF), etc.), thermoplastic resins such as polyethylene, polypropylene, polyacrylic, and polyimide; ethylene-propylene-diene rubber (EPDM), sulfone. Examples thereof include elastomers such as polyethyleneized EPDM, styrene butadiene rubber (SBR), and fluororubber; and polysaccharide polymers.

The filler is not particularly limited. Fillers include polyolefins such as polypropylene and polyethylene, silicon dioxide, alumina, titanium dioxide, calcium oxide, strontium oxide, barium oxide, magnesium oxide, inorganic oxides such as aluminosilicate, magnesium hydroxide, calcium hydroxide, and hydroxide. Hydroxides such as aluminum, carbonates such as calcium carbonate, sparingly soluble ion crystals such as calcium fluoride, barium fluoride, barium sulfate, nitrides such as aluminum nitride and silicon nitride, talc, montmorillonite, boehmite, zeolite, etc. Examples thereof include mineral resource-derived substances such as apatite, kaolin, mulite, spinel, olivine, sericite, bentonite, and mica, or man-made products thereof.

The lower limit of the average thickness of the negative electrode mixture layer 5 is preferably 30 μm, more preferably 60 μm. The upper limit of the average thickness of the negative electrode mixture layer 5 is preferably 1000 μm, more preferably 500 μm, and even more preferably 200 μm. By setting the average thickness of the negative electrode mixture layer 5 to be equal to or greater than the above lower limit, an all-solid-state battery having a high energy density can be obtained. By setting the average thickness of the negative electrode mixture layer 5 to be equal to or less than the above upper limit, it is possible to obtain an all-solid-state battery having a negative electrode having excellent high rate discharge performance and high active material utilization rate.

(Middle layer)
The intermediate layer is a coating layer on the surface of the negative electrode base material 4, and contains conductive particles such as carbon particles to reduce the contact resistance between the negative electrode base material 4 and the negative electrode mixture layer 5. The composition of the intermediate layer is not particularly limited, and can be formed by, for example, a composition containing a resin binder and conductive particles.

[Solid electrolyte layer]
The solid electrolyte layer 3 contains an electrolyte for the solid electrolyte layer. Examples of the electrolyte for the solid electrolyte layer include oxide-based solid electrolytes, other sulfide solid electrolytes, dry polymer electrolytes, gel polymer electrolytes, and pseudo-solid electrolytes, in addition to the above-mentioned composite solid electrolytes. Among these, a sulfide solid electrolyte is preferable from the viewpoint of good ionic conductivity and easy interface formation, and the composite solid electrolyte is more preferable. Since the solid electrolyte layer 3 contains the composite solid electrolyte, the reduction resistance of the composite solid electrolyte can be improved while maintaining high ionic conductivity, so that the effect of suppressing the decrease in Coulomb efficiency in the charge / discharge cycle is excellent. ..

The electrolyte for the solid electrolyte layer may have a crystal structure or may be amorphous without a crystal structure. Oxides such as Li ₃ PO ₄ , halogens, halogen compounds and the like may be added to the electrolyte for the solid electrolyte layer.

The lower limit of the average thickness of the solid electrolyte layer 3 is preferably 1 μm, more preferably 3 μm. The upper limit of the average thickness of the solid electrolyte layer 3 is preferably 50 μm, more preferably 20 μm. By setting the average thickness of the solid electrolyte layer 3 to be equal to or greater than the above lower limit, it is possible to reliably insulate the positive electrode and the negative electrode. By setting the average thickness of the solid electrolyte layer 3 to be equal to or less than the above upper limit, it is possible to increase the energy density of the all-solid-state battery.

[Positive electrode]
The positive electrode 2 includes a positive electrode base material 7 and a positive electrode mixture layer 6 laminated on the surface of the positive electrode base material 7. Like the negative electrode 1, the positive electrode 2 may have an intermediate layer between the positive electrode base material 7 and the positive electrode mixture layer 6. This intermediate layer can have the same configuration as the intermediate layer of the negative electrode 1.

(Positive electrode base material)
The positive electrode base material 7 can have the same configuration as the negative electrode base material 4. The material of the positive electrode base material 7 is not limited as long as it is a conductor. For example, copper, aluminum, titanium, nickel, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth, antimony, gold, silver, iron, platinum, chromium, tin, indium and alloys containing one or more of these, as well as stainless steel. One or more metals selected from the group consisting of alloys can be mentioned.

As the lower limit of the average thickness of the positive electrode base material 7, 3 μm is preferable, and 5 μm is more preferable. The upper limit of the average thickness of the positive electrode base material 7 is preferably 200 μm, more preferably 100 μm, and even more preferably 50 μm. By setting the average thickness of the positive electrode base material 7 to be equal to or greater than the above lower limit, the strength of the positive electrode base material 7 can be sufficiently increased, so that the positive electrode 2 can be formed satisfactorily. By setting the average thickness of the positive electrode base material 7 to be equal to or less than the above upper limit, it is possible to sufficiently secure the volume of other components.

(Positive electrode mixture layer)
The positive electrode mixture layer 6 can be formed from a so-called positive electrode mixture containing a positive electrode active material. The positive electrode mixture may contain a mixture or a composite containing the positive electrode active material and the above-mentioned sulfide solid electrolyte. The positive electrode mixture may contain the above-mentioned sulfide solid electrolyte which does not form a mixture or a complex with the positive electrode active material. The sulfide solid electrolyte may be the composite solid electrolyte. Like the negative electrode mixture, the positive electrode mixture forming the positive electrode mixture layer 6 contains optional components such as a solid electrolyte other than the sulfide solid electrolyte, a conductive agent, a binder, and a filler, if necessary.

<Positive electrode active material>
As the positive electrode active material contained in the positive electrode mixture layer 6, known materials usually used for all-solid-state batteries can be used. As the positive electrode active material, a material capable of occluding and releasing lithium ions is usually used as the positive electrode active material. Examples of the positive electrode active material include a lithium transition metal composite oxide having an α-NaFeO type ₂ crystal structure, a lithium transition metal composite oxide having a spinel type crystal structure, a polyanionic compound, a chalcogen compound, sulfur and the like. Examples of the lithium transition metal composite oxide having an α-NaFeO type ₂ crystal structure include Li [Li _x Ni _1-x ] O ₂ (0 ≦ x <0.5) and Li [Li _x Ni _γ Co _(1- ). _x-γ) ] O ₂ (0 ≦ x <0.5, 0 <γ <1), Li [Li _x Co _(1-x) ] O ₂ (0 ≦ x <0.5), Li [Li _x Ni _γ Mn _(1-x-γ) ] O ₂ (0 ≦ x <0.5, 0 <γ <1), Li [Li _x Ni _γ Mn _β Co _(1-x-γ-β) ] O ₂ (0≤x <0.5, 0 <γ, 0 <β, 0.5 <γ + β <1), Li [Li _x Ni _γ Co _β Al _(1-x-γ-β) ] O ₂ (0≤ Examples thereof include x <0.5, 0 <γ, 0 <β, 0.5 <γ + β <1). Examples of the lithium transition metal composite oxide having a spinel-type crystal structure include Li _x Mn ₂ O ₄ and Li _x Ni _γ Mn _(2-γ) O ₄ . Examples of the polyanionic compound include LiFePO ₄ , LiMnPO ₄ , LiNiPO ₄ , LiCoPO ₄ , Li ₃ V ₂ (PO ₄ ) ₃ , Li ₂ MnSiO ₄ , Li ₂ CoPO ₄ F and the like. Examples of the chalcogen compound include titanium disulfide, molybdenum disulfide, molybdenum dioxide and the like. The atoms or polyanions in these materials may be partially substituted with atoms or anion species consisting of other elements. The surface of these materials may be coated with other materials. In the positive electrode active material layer, one of these materials may be used alone, or two or more of them may be mixed and used. In the positive electrode mixture layer 6, one of these compounds may be used alone, or two or more thereof may be mixed and used.

Further, as the positive electrode active material, Li-Al, Li-In, Li-Sn, Li-Pb, Li-Bi, Li-Ga, Li-Sr, Li-Si, Li-Zn, Li-Cd, Li- The reaction potential of lithium alloys such as Ca and Li-Ba and compounds other than the compounds represented by the above general formulas such as MnO ₂ , FeO ₂ , TiO ₂ , V ₂ O ₅ , V ₆ O ₁₃ , and TiS ₂ is higher than that of the negative electrode material. Can also use precious materials.

The lower limit of the content of the positive electrode active material in the positive electrode mixture is preferably 10% by mass, more preferably 15% by mass. The upper limit of the content of the positive electrode active material is preferably 60% by mass, more preferably 70% by mass, further preferably 80% by mass, still more preferably 90% by mass, and particularly preferably 95% by mass. By setting the content of the positive electrode active material in the above range, the electric capacity of the all-solid-state battery can be increased.

<Mixture or complex>
The above-mentioned mixture is a mixture produced by mixing the positive electrode active material, the above-mentioned sulfide solid electrolyte, and the like by mechanical milling or the like. For example, the mixture of the positive electrode active material and the sulfide solid electrolyte and the like can be obtained by mixing the particulate positive electrode active material and the particulate sulfide solid electrolyte and the like.
The composite includes a composite having a chemical or physical bond between the positive electrode active material and the sulfide solid electrolyte, and a composite in which the positive electrode active material, the sulfide solid electrolyte, and the like are mechanically complexed. And so on. In the composite, the positive electrode active material, the sulfide solid electrolyte, and the like are present in one particle, and for example, the positive electrode active material and the sulfide solid electrolyte and the like form an aggregated state. Examples thereof include those in which a film containing the above-mentioned sulfide solid electrolyte or the like is formed on at least a part of the surface of the positive electrode active material.

When the positive electrode mixture contains a solid electrolyte, the lower limit of the content of the solid electrolyte may be 5% by mass, preferably 10% by mass. The upper limit of the content of the solid electrolyte in the positive electrode mixture is preferably 90% by mass, more preferably 85% by mass, further preferably 80% by mass, and particularly preferably 75% by mass. By setting the content of the solid electrolyte in the above range, the electric capacity of the all-solid-state battery can be increased.

The lower limit of the average thickness of the positive electrode mixture layer 6 is preferably 30 μm, more preferably 60 μm. The upper limit of the average thickness of the positive electrode mixture layer 6 is preferably 1000 μm, more preferably 500 μm, and even more preferably 200 μm. By setting the average thickness of the positive electrode mixture layer 6 to be equal to or greater than the above lower limit, an all-solid-state battery having a high energy density can be obtained. By setting the average thickness of the positive electrode mixture layer 6 to be equal to or less than the above upper limit, it is possible to obtain an all-solid-state battery having a positive electrode having excellent high rate discharge performance and high active material utilization rate.

<Manufacturing method of composite solid electrolyte>
The method for producing the composite solid electrolyte comprises mixing the sulfide solid electrolyte and the additive to prepare the composite solid electrolyte. As the additive, the above-mentioned sulfur-based cyclic compound having an S = O bond, lithium nitrate, or a combination thereof is used.

Examples of the method for producing the above-mentioned composite solid electrolyte include (1) a method of first synthesizing a sulfide solid electrolyte and then mixing an additive to synthesize a composite solid electrolyte, and (2) a starting material for the sulfide solid electrolyte. And an additive are mixed to prepare a composite solid electrolyte precursor containing the additive, and then a method of synthesizing the composite solid electrolyte from the composite solid electrolyte precursor and the like can be mentioned.

(1) Method for synthesizing a composite solid electrolyte containing an additive after synthesizing a sulfide solid electrolyte In this method, a composite solid electrolyte synthesis step is performed after the sulfide solid electrolyte synthesis step.

(Sulfide solid electrolyte synthesis process)
In this step, for example, a sulfide solid electrolyte is produced by the following procedure.
After mixing the starting materials (Li ₂ S, P ₂ S ₅ , etc.) of the sulfide solid electrolyte having a predetermined molar ratio in a mortar or the like, the sulfide solid electrolyte is prepared. As a method for producing the sulfide solid electrolyte, for example, a mechanical milling method, a melt quenching method, or the like can be used.
In the case of producing the sulfide solid electrolyte glass ceramics, the sulfide solid electrolyte glass ceramics can be produced by heat-treating at a crystallization temperature or higher after producing the sulfide solid electrolyte. The crystallization temperature can be determined by measurement with a differential scanning calorimetry (DSC).

(Composite solid electrolyte synthesis process)
In this step, for example, the sulfide solid electrolyte and the additive are mixed by using a mechanical milling method or the like, and the sulfide solid electrolyte and the additive are mixed to synthesize a composite solid electrolyte. The preferable range of the content ratio of the additive in the composite solid electrolyte is as described above.

(2) Method for synthesizing a composite solid electrolyte after mixing the starting material of the sulfide solid electrolyte and the additive In this method, the starting material of the sulfide solid electrolyte (Li ₂ S, P ₂ S ₅ , etc.) and the addition are added. Mix with the agent to make a composite solid electrolyte precursor containing the additive. After that, the composite solid electrolyte can be produced by, for example, a mechanical milling method, a melt quenching method, a heat treatment, or the like.

Since the method for producing the composite solid electrolyte comprises mixing the sulfide solid electrolyte and the above additive to prepare the composite solid electrolyte, it has reduction resistance and has a Coulomb efficiency in the charge / discharge cycle of the all-solid-state battery. It is possible to produce a composite solid electrolyte having an excellent effect of suppressing the decrease in the amount.

<Manufacturing method of all-solid-state battery>
The method for producing the all-solid-state battery comprises producing at least one of the negative electrode and the electrolyte layer using the composite solid electrolyte or the composite solid electrolyte obtained by the method for manufacturing the composite solid electrolyte. In addition, the method for manufacturing the all-solid-state battery includes, for example, a negative electrode mixture manufacturing step, an electrolyte manufacturing step for a solid electrolyte layer, a positive electrode mixture manufacturing step, and a negative electrode, a solid electrolyte layer, and a positive electrode as other steps. It may be provided with a laminating step. The details of the composite solid electrolyte and the composite solid electrolyte obtained by the method for producing the composite solid electrolyte are as described above.

(Negative electrode mixture manufacturing process)
In this step, a negative electrode mixture for forming a negative electrode is produced. When the negative electrode mixture contains a mixture or a composite containing the negative electrode active material and the composite solid electrolyte, in this step, the negative electrode active material and the composite solid electrolyte are mixed by using, for example, a mechanical milling method or the like. It is provided to prepare a mixture or a composite of the negative electrode active material and the composite solid electrolyte. Further, the negative electrode mixture may be prepared without using the above mechanical milling method. In this case, for example, it may be provided to prepare a negative electrode mixture paste containing a negative electrode active material, a solid electrolyte, a conductive agent, etc., and to apply it to a negative electrode base material. When the negative electrode mixture contains the composite solid electrolyte, the composite solid electrolyte or the composite solid electrolyte obtained by the method for producing the composite solid electrolyte is used.

(Solid electrolyte layer fabrication process)
In this step, a solid electrolyte layer is produced. In this step, a predetermined material of the electrolyte for the solid electrolyte layer can be obtained by treating it by a mechanical milling method. An electrolyte for a solid electrolyte layer may be produced by heating a predetermined material of an electrolyte for a solid electrolyte layer to a melting temperature or higher by a melt quenching method, melting and mixing the two at a predetermined ratio, and quenching. Other methods for synthesizing the electrolyte for the solid electrolyte layer include, for example, a solid phase method of encapsulating and firing under reduced pressure, a liquid phase method such as dissolution precipitation, a gas phase method (PLD), and a method of firing in an argon atmosphere after mechanical milling. Can be mentioned. When the electrolyte for the solid electrolyte layer is the composite solid electrolyte, the composite solid electrolyte or the composite solid electrolyte obtained by the method for producing the composite solid electrolyte is used as the electrolyte for the solid electrolyte layer.

(Positive electrode mixture manufacturing process)
In this step, a positive electrode mixture for forming a positive electrode is produced. The method for producing the positive electrode mixture is not particularly limited and may be appropriately selected depending on the intended purpose. For example, compression molding of the positive electrode active material, mechanical milling treatment of a predetermined material of the positive electrode mixture, sputtering using the target material of the positive electrode active material, and the like can be mentioned. When the positive electrode mixture contains a mixture or a composite containing a positive electrode active material and a sulfide solid electrolyte, in this step, the positive electrode active material and the sulfide solid electrolyte are mixed by using, for example, a mechanical milling method or the like. , A mixture or a composite of a positive electrode active material and a sulfide solid electrolyte. Further, as in the negative electrode mixture manufacturing step, the positive electrode mixture may be manufactured without using the mechanical milling method. In this case, for example, it may be provided to prepare a positive electrode mixture paste containing a positive electrode active material, a solid electrolyte, a conductive agent, etc., and to apply it to a positive electrode base material.

(Laminating process)
In this step, a negative electrode having a negative electrode base material and a negative electrode mixture layer, a solid electrolyte layer, and a positive electrode having a positive electrode base material and a positive electrode mixture layer are laminated. In this step, the negative electrode, the solid electrolyte layer, and the positive electrode may be sequentially laminated, or vice versa, and the order of laminating each layer is not particularly limited. The negative electrode is formed by, for example, pressure molding a negative electrode base material and a negative electrode mixture, the solid electrolyte layer is formed by pressure molding, for example, an electrolyte for a solid electrolyte layer, and the positive electrode is, for example, a positive electrode. It is formed by pressure molding the base material and the positive electrode mixture.

The negative electrode, the solid electrolyte layer, and the positive electrode may be laminated by pressure-molding the negative electrode base material, the negative electrode mixture, the electrolyte for the solid electrolyte layer, the positive electrode base material, and the positive electrode mixture at one time. The positive electrode, the negative electrode, or these layers may be preformed, pressure-molded with the solid electrolyte layer, and laminated.

The method for manufacturing the all-solid-state battery comprises using the composite solid electrolyte or the composite solid electrolyte obtained by the method for manufacturing the composite solid electrolyte to prepare at least one of the negative electrode and the electrolyte layer. It is possible to manufacture an all-solid-state battery having an excellent effect of suppressing a decrease in Coulomb efficiency in a cycle.

[Other embodiments]
The present invention is not limited to the above embodiment, and can be implemented in various modifications and improvements in addition to the above embodiment.

As another configuration, the all-solid-state battery according to the present invention may include a layer other than the negative electrode, the positive electrode, and the solid electrolyte layer, such as an intermediate layer and an adhesive layer.

<Example>
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

[Preparation of composite solid electrolyte]
(Example 1)
Li ₂ S (99.98% by mass, manufactured by Aldrich) and P ₂ S ₅ (99% by mass, manufactured by Aldrich) in a glove box having an argon atmosphere with a dew point of -50 ° C or less so as to have a molar ratio of 75:25. After weighing, it was mixed in a mortar. This mixed sample was placed in a closed zirconia pot. A planetary ball mill (manufactured by FRITSCH, model number Premium line P-7) was used for milling at a revolution speed of 510 rpm for 45 hours to obtain _75Li 2S / 25P ₂ S ₅ .

Next, _75Li 2S / _{25P 2S 5 and} lithium nitrate as an additive are weighed and mixed so as to have a mass ratio of 90:10, and then mechanically used at a revolution speed of 370 rpm for 2 hours using a planetary ball mill. By milling, the composite solid electrolyte of Example 1 was synthesized.

(Example 2)
The composite solid electrolyte of Example 2 was synthesized in the same manner as in Example 1 except that the additive was changed to 1,3-propensultone (PRS), which is a cyclic sulfonic acid ester.

(Comparative Example 1)
The 75Li ₂ S / 25P ₂ S ₅ before mixing the additive in Example 1 was designated as Comparative Example 1.

(Comparative Example 2)
The composite solid electrolyte of Comparative Example 2 was synthesized in the same manner as in Example 1 except that the additive was changed to lithium iodide.

[Preparation of reduction resistance evaluation cell]
120 mg of each of the solid electrolytes of Example 1, Example 2, Comparative Example 1 and Comparative Example 2 was inserted into a polycarbonate tube having an inner diameter of 10 mm, and then pressure-molded at 360 MPa. After the pressure was released, the metal Li foil was bonded to the counter electrode side and the metal ln foil was bonded to the working electrode side, and then pressure-molded at 120 MPa to obtain pellets. A cell for evaluation of reduction resistance was produced by inserting this into an HS cell manufactured by Hosen. The pellets in each reduction resistance evaluation cell are in a state of being pressurized by about 5 MPa by the spring in the HS cell.

[evaluation]
(Charge / discharge cycle test: Coulomb efficiency)
(1) Charge / discharge cycle test After each reduction resistance evaluation cell is stored in a constant temperature bath at 50 ° C. for 30 minutes, constant current constant voltage charge / discharge with a current density of 0.1 mAhcm ^-1 and a charge / discharge time of 10 hours is performed. gone. Charging was performed with a charge termination voltage of 0.2 V. The discharge was set to a discharge end voltage of 1.1 V. After the charging and discharging steps, there was a 30-minute rest, respectively. With these charging and discharging steps as one cycle, Example 1, Example 2, and Comparative Example 1 were repeated for 3 cycles, and Comparative Example 2 was repeated for 4 cycles. Charging, discharging and pausing were performed in a constant temperature bath at 50 ° C.
(2) Coulomb efficiency For each reduction resistance evaluation cell in the charge / discharge cycle test, the percentage of the discharge capacity (Ah) in 1 to 5 cycles to the charge electricity amount (Ah) in 1 to 5 cycles is set to "1 to 5 cycles". It was calculated as "Coulomb efficiency (%)". The results are shown in FIG.

As shown in FIG. 2, the composite solid electrolytes of Examples 1 and 2 containing a sulfur-based cyclic compound having an S = O bond or lithium nitrate as an additive are Comparative Example 1 and an additive containing no additive. As compared with Comparative Example 2 containing lithium iodide, the effect of suppressing the decrease in sulfur efficiency in the charge / discharge cycle was excellent.

From the above results, it was shown that the composite solid electrolyte according to one aspect of the present invention can suppress a decrease in the Coulomb efficiency in the charge / discharge cycle of the all-solid-state battery.

Since the composite solid electrolyte and the all-solid-state battery according to the present invention have an excellent effect of suppressing a decrease in Coulomb efficiency in the charge / discharge cycle, they are suitably used as, for example, an all-solid-state battery for HEV and a solid electrolyte used therein.

1 Negative electrode 2 Positive electrode 3 Solid electrolyte layer 4 Negative electrode base material 5 Negative electrode mixture layer 6 Positive electrode mixture layer 7 Positive electrode base material 10 All-solid-state battery

Claims (7)

Containing sulfide solid electrolytes and additives,
A composite solid electrolyte in which the additive is a sulfur-based cyclic compound having an S = O bond, lithium nitrate, or a combination thereof. The composite solid electrolyte according to claim 1, wherein the content ratio of the additive in the composite solid electrolyte is 5% by mass or more and 20% by mass or less. The composite solid electrolyte according to claim 1 or 2, wherein the sulfur-based cyclic compound is a cyclic sulfonic acid ester. A negative electrode, a positive electrode, and an electrolyte layer interposed between the negative electrode and the positive electrode are provided.
An all-solid-state battery in which the negative electrode, the electrolyte layer, or a combination thereof contains the composite solid electrolyte of claim 1, claim 2 or claim 3. The sulfide solid electrolyte and the additive are mixed to prepare a composite solid electrolyte.
A method for producing a sulfur-based cyclic compound having an S = O bond, lithium nitrate, or a combination thereof, wherein the additive is a composite solid electrolyte. The method for producing a composite solid electrolyte according to claim 5, wherein the content ratio of the additive in the composite solid electrolyte is 5% by mass or more and 20% by mass or less. Using the composite solid electrolyte of claim 1, claim 2 or claim 3 or the composite solid electrolyte obtained by the method for producing the composite solid electrolyte of claim 5, at least one of the negative electrode and the electrolyte layer can be produced. A method for manufacturing an all-solid-state battery.

Images