JP2013069415A - Negative electrode mixture and all-solid lithium-ion battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a negative electrode mixture which is capable of suppressing a voltage abnormality during charging with at least 0.4 C when used for an all-solid lithium-ion battery.SOLUTION: The negative electrode mixture for a lithium-ion battery contains an Si powder doped with a dopant into a P-type, and an inorganic solid electrolyte powder.

Description

  The present invention relates to a negative electrode mixture and an all solid lithium ion battery using the same.

  In the current lithium ion battery, an organic electrolyte is mainly used as an electrolyte. Although organic electrolytes exhibit high ionic conductivity, the electrolytes are liquid and flammable, so there are concerns about risks such as leakage and ignition when used as batteries. As a next-generation lithium ion battery that solves this problem, an all-solid-state lithium ion battery that uses a safer solid electrolyte is expected.

As an all-solid-state lithium ion battery, a sulfide-based solid electrolyte containing sulfur, lithium and phosphorus as main components is used, a metal or an alloy is used for the negative electrode active material, and LiMO ₂ (M = Ni) is used for the positive electrode active material. , Co, etc.) is disclosed (Patent Document 1).
As described in Patent Document 1, although the capacity of the battery can be increased by using a metal or alloy as the negative electrode active material, the voltage was not stable during high-rate charging, for example, charging at 0.4C. . There has been a demand for further stabilization of all-solid-state lithium ion batteries.

JP 2010-003679 A

An object of the present invention is to provide a negative electrode mixture capable of suppressing voltage abnormality during charging at least at 0.4 C when used in a lithium ion battery.
The objective of this invention is providing the lithium ion battery which can suppress the voltage abnormality at the time of charge by at least 0.4C.

  As a result of intensive research, the present inventors have found that in an all-solid-state lithium ion battery using a metal or alloy as a negative electrode active material, the voltage does not increase monotonously during charging, and the phenomenon of unstable voltage ( In the following, it was found that voltage abnormality is likely to occur), and voltage abnormality can be suppressed by using a negative electrode mixture containing Si powder doped with P-type dopant and inorganic solid electrolyte powder.

According to the present invention, the following negative electrode mixture and the like are provided.
1. A negative electrode mixture for a lithium ion battery, comprising Si powder doped in a P-type with a dopant and an inorganic solid electrolyte powder.
2. 2. The negative electrode composite material according to 1, wherein the dopant contains one or more selected from B, Al, Ga, and In.
3. 3. The negative electrode composite material according to 1 or 2, wherein the Si powder has an average particle size of 20 μm or less.
4). The negative electrode composite material according to any one of 1 to 3, wherein an electronic conductivity of the green compact obtained by pressing the Si powder at 141 MPa is 10 ⁻⁴ S / cm or more.
5. The negative electrode composite material according to any one of 1 to 4, wherein the inorganic solid electrolyte powder is a sulfide-based solid electrolyte powder.
6). The negative electrode mixture according to any one of 1 to 5, wherein a weight ratio of the Si powder to the inorganic solid electrolyte powder is 95: 5 to 30:70.
A negative electrode layer comprising the negative electrode mixture according to any one of 7.1 to 6.
The negative electrode layer manufactured using the negative electrode compound material in any one of 8.1-6.
An all-solid-state lithium ion battery including the negative electrode layer according to 9.7 or 8, a solid electrolyte layer, and a positive electrode layer.
10. An all-solid-state lithium ion battery including a negative electrode layer containing Si powder doped in a P-type with a dopant, a solid electrolyte layer, and a positive electrode layer.

ADVANTAGE OF THE INVENTION According to this invention, when using for an all-solid-state lithium ion battery, the negative electrode compound material which can suppress the voltage abnormality at the time of charge by at least 0.4C can be provided.
According to the present invention, it is possible to provide an all-solid-state lithium ion battery capable of suppressing voltage abnormality during charging at at least 0.4C.

It is a figure which shows the method of measuring the electronic conductivity of the green compact of P type dope Si powder. It is a figure which shows the potential-capacitance curve of a half cell at the time of performing Li ion insertion by 0.5 mA / cm < ² > by constant current (CC) about the half cell of Example 1. FIG.

The negative electrode mixture of the present invention includes Si powder (hereinafter sometimes simply referred to as P-type doped Si powder) doped with P-type by a dopant, and inorganic solid electrolyte powder.
By doping the Si particles with a dopant P-type, it is possible to suppress the precipitation of Li metal on the Si surface when Li ions are inserted into the Si particles, thereby causing voltage abnormalities during charging of the all-solid-state lithium ion battery. Can be suppressed.

In addition, the generation mechanism of the voltage abnormality at the time of charging is considered as follows.
When Si particles are used as the negative electrode active material, a Li insertion reaction into the Si particles occurs during charging. When the charge rate is increased, current concentrates at the Li insertion reaction site into the Si particles, and a part of Li is not inserted into the Si particles, and Li metal may be deposited on the surface of the Si particles. As the deposition of Li metal proceeds, Li metal extends through the electrolyte to the positive electrode, causing a short circuit and a voltage drop. Thereafter, the Li metal in the vicinity of the positive electrode is instantly ionized, so that the voltage rises again. By repeating this voltage drop and rise, the voltage at the time of charging becomes unstable. Thus, it is considered that the deposition of Li metal on the surface of the Si particles causes the voltage abnormality.
This voltage abnormality at the time of charging is a phenomenon that is not considered much because the contact area between the Si particles and the electrolyte is sufficiently secured in a lithium ion battery using a liquid electrolyte, and is a solid electrolyte with few reaction sites. It is considered that this phenomenon is likely to occur during use.

Hereinafter, each member of the negative electrode mixture of the present invention will be described.
[P-type doped Si powder]
In the present invention, when the Si particles are doped into P-type, the electronic conductivity of the Si particles is increased, and the Li insertion reaction site existing at the interface between the Si particles and the inorganic solid electrolyte becomes more functional. During charging, Li is smoothly inserted into the Si particles. Thereby, it is considered that Li metal hardly deposits on the surface of the Si particles, and voltage abnormality hardly occurs.
In addition, Li atoms are easily cationized, and dopant atoms such as B and Al atoms in P-doped Si particles are anionized. Therefore, Li ions are easily cationized when Li ions are inserted into Si particles. An attractive force is generated between the atom and the dopant atom. This attractive force makes it easier for Li ions to be inserted into the Si particles and makes it difficult for Li metal to precipitate on the surface of the Si particles.
On the other hand, when Si particles doped with N-type dopants are used, dopant atoms such as P and Sb are cationized. Therefore, when Li is inserted into Si particles, between Li atoms and dopant atoms that are easily cationized. Repulsive force is generated. This repulsive force makes it difficult for Li ions to be inserted into the Si particles, and Li metal is likely to be deposited on the surface of the Si particles, so that voltage abnormality is likely to occur.

A P-type semiconductor is a semiconductor in which current is generated by the movement of positively charged holes and the holes become majority carriers. For example, a small amount of a trivalent element is added to an intrinsic semiconductor of Si, which is a tetravalent element. It can be prepared by adding as an impurity.
Accordingly, the dopant of the Si particles is preferably one or more elements selected from B, Al, Ga and In, more preferably one or more elements selected from B and Al, having a trivalent element form. It is.

It is preferable that the dopant amount of the P-type doped Si powder is doped with 1 × 10 ¹⁷ to 1 × 10 ²⁰ dopant atoms with respect to 1 cm ³ of Si powder.

The average particle size of the P-type doped Si powder is preferably 20 μm or less and 1 nm or more, more preferably 10 μm or less and 10 nm or more, and further preferably 5 μm or less and 50 nm or more.
In the case of the P-type doped Si powder used as the wafer plate and the P-type doped Si powder having an average particle size of 20 μm or less, the contact between the inorganic solid electrolyte particles and the Si particles is better maintained, and the number of reaction sites increases. Li metal is less likely to be deposited on the surface, which makes voltage abnormality less likely to occur. On the other hand, if the P-type doped Si powder has an average particle size of 1 nm or more, the production cost is lower than that of the P-type doped Si powder having an average particle size of less than 1 nm.

The average particle diameter of the P-type doped Si powder is measured by a laser diffraction particle size distribution measuring method. The laser diffraction particle size distribution measurement method can measure the particle size distribution without drying the composition, and the particle size distribution is measured by irradiating a particle group in the composition with laser and analyzing the scattered light. can do.
As the expression method of average particle size, expressed by the median diameter (50% _{diameter, D 50).} Median diameter represents the particle size distribution in the distribution of the number of particles accumulated, in which the particle size when the cumulative number particle is 50% of the total number expressed as D _50.

P-type doped Si powder having the above average particle diameter is obtained by using a mortar, ball mill, bead mill, jet mill, planetary ball mill, vibrating ball mill, sand mill, cutter mill, etc. It can obtain easily by grind | pulverizing and sieving the obtained ground material.
The pulverization may be performed by either wet pulverization or dry pulverization, and the implementation means is not limited to the above.

The P-type doped Si powder preferably has a green compact of P-type doped Si powder having an electron conductivity of 10 ⁻⁴ S / cm or more, more preferably 10 ⁻³ S / cm or more, and even more preferably 10 ^-2 S / cm or more.
In the P-type doped Si powder whose green powder has an electron conductivity of less than 10 ⁻⁴ S / cm, Li ions are hard to be occluded inside the Si particles, and deposition of metallic Li occurs on the surface of the Si particles. There is a risk of abnormal voltage.

The electronic conductivity of the green compact of the P-type doped Si powder can be measured by the method shown in FIG.
First, the P-type doped Si powder 20 is put in a ceramic cylindrical container 10, and the resistance of the Si powder compact is measured by the two-terminal method while applying pressure from the upper and lower parts of the cylindrical container 10 by the pressurizing means 30 and 32. Measure. At this time, pressurization is performed until the resistance value of the green compact of the P-type doped Si powder becomes constant, and the thickness of the green compact at this time is also measured.
The resistance and thickness of the green compact are measured while pressing at 141 MPa.

By applying the resistance and thickness values of the green compact obtained by the above method to the following equation, the electronic conductivity of the green compact of the P-type doped Si powder can be obtained:
σ = L / (R · S)
σ: electron conductivity [S / cm]
L: Green compact thickness [cm]
R: Resistance value [Ω]
S: Cross-sectional area of cylindrical container [cm ² ]

The P-type doped Si powder can be produced, for example, by pulverizing a commercially available P-type doped Si wafer.
The dopant doping method can be carried out by a known method disclosed in JP-A-10-199524, for example, CZ method (Czochralski method or pulling method), FZ method (floating zone method), alloy method, Examples include, but are not limited to, diffusion methods, ion implantation methods, and epitaxial methods.

[Inorganic solid electrolyte powder]
The average particle size of the inorganic solid electrolyte powder is preferably 10 nm to 50 μm, more preferably 30 nm to 20 μm.
The inorganic solid electrolyte powder having the above average particle diameter is, for example, an inorganic solid electrolyte wafer, lump or coarse particle having an average particle diameter larger than the above, mortar, ball mill, bead mill, jet mill, planetary ball mill, vibration ball mill, It can obtain easily by grind | pulverizing using a sand mill, a cutter mill, etc., and sieving the obtained ground material. The inorganic solid electrolyte powder having the above average particle diameter can be used as it is.

The average particle diameter of the inorganic solid electrolyte powder is a volume-based average particle diameter (Mean Volume Diameter), and is measured by a laser diffraction particle size distribution measurement method.
In the present invention, the average particle size of the inorganic solid electrolyte powder is determined by measuring the average particle size of the dried inorganic solid electrolyte powder.

When the laser diffraction type particle size distribution measuring device for measuring the average particle size is Master Sizer 2000 manufactured by Malvern Instruments Ltd, the specific measurement procedure is as follows.
First, 110 ml of dehydrated toluene (Wako Pure Chemicals, product name: special grade) was placed in the dispersion tank of the apparatus, and 6% of dehydrated tertiary butyl alcohol (Wako Pure Chemicals, special grade) was added as a dispersant. Added. After sufficiently mixing this mixture, “dry solid electrolyte powder” is added and the particle size is measured. The amount of the dried solid electrolyte powder added is adjusted so that the laser scattering intensity corresponding to the particle concentration falls within the specified range (10 to 20%) on the operation screen specified by the master sizer 2000. If this range is exceeded, multiple scattering may occur, and an accurate particle size distribution may not be obtained. On the other hand, when the amount is less than this range, the SN ratio is deteriorated, and there is a possibility that accurate measurement cannot be performed. In Master Sizer 2000, the laser scattering intensity is displayed based on the added amount of the dried solid electrolyte powder.
The amount of the dried solid electrolyte powder added is generally about 0.01 g to 0.05 g, although the optimum amount varies depending on the type of the ion conductive substance.

  Examples of the inorganic solid electrolyte particles constituting the inorganic solid electrolyte powder include particles made of (1) an oxide solid electrolyte or (2) a sulfide solid electrolyte.

(1) Oxide-based solid electrolytes As oxide-based solid electrolytes, LiN, LISICONs; Thio-LISICONs; LiTi ₂ P ₃ O ₁₂ having a NASICON type structure, and an electrolyte obtained by crystallizing them; La _0. A crystal having a perovskite structure such as ₅₅ Li _0.35 TiO ₃ can be used.

(2) Sulfide-based solid electrolyte The sulfide-based solid electrolyte is a lithium ion conductive inorganic solid electrolyte that satisfies the composition represented by the following formula (1), for example.
Li _{a Mb} P _c S _d (1)
(In the formula, M represents an element selected from B, Zn, Si, Cu, Ga and Ge. Ad represents the composition ratio of each element, and a: b: c: d represents 1 to 12: 0-0.2: 1: 2-9 are satisfied.)

In the formula (1), the composition ratio of Li, M, P and S is preferably such that b is 0, more preferably b = 0 and the ratio of a, c and d (a: c: d) is a. : C: d = 1-9: 1: 3-7, more preferably b = 0 and a: c: d = 1.5-4: 1: 3.25-4.5.
The composition ratio of each element can be controlled by adjusting the blending amount of the raw material compound when producing the sulfide-based solid electrolyte as described below.

The sulfide-based solid electrolyte may be amorphous (glass) or crystallized (glass ceramic), or only a part may be crystallized.
Here, when crystallized, the ion conductivity may be higher than that of glass. In that case, it is preferable to crystallize.

The crystal structure of the crystallized sulfide-based solid electrolyte is preferably Li ₇ PS ₆ structure, Li ₄ P ₂ S ₆ structure, Li ₃ PS ₄ structure, Li ₄ SiS ₄ structure disclosed in JP-A-2002-109955, Li ₂ SiS ₃ structure, or Li ₇ P ₃ S ₁₁ structure disclosed in Japanese Patent Application Laid-Open No. 2005-228570 and WO 2007/066539, and most preferably Li ₇ P ₃ S ₁₁ structure.
The crystallized portion of the crystallized sulfide solid electrolyte only needs to have any one of these crystal structures, and may have a plurality of crystal structures. Crystallized sulfide solid electrolytes having these crystal structures can exhibit higher ionic conductivity than amorphous sulfide solid electrolytes.
For example, the Li ₇ P ₃ S ₁₁ structure has 2θ = 17.8 ± 0.3 deg, 18.2 ± 0.3 deg, 19.8 ± 0. 0 in X-ray diffraction (CuKα: λ = 1.5418４). It has diffraction peaks at 3 deg, 21.8 ± 0.3 deg, 23.8 ± 0.3 deg, 25.9 ± 0.3 deg, 29.5 ± 0.3 deg, 30.0 ± 0.3 deg.

The degree of crystallinity of the crystallized sulfide-based solid electrolyte (the degree of crystallinity of the crystal structure having higher ionic conductivity than that of the amorphous body) is preferably 50% or more, more preferably 60% or more.
When the crystallinity of the crystallized sulfide-based solid electrolyte is less than 50%, the effect of increasing the ionic conductivity by crystallization may be reduced.

The degree of crystallinity can be measured by using an NMR spectrum apparatus. Specifically, the solid ³¹ P-NMR spectrum of the crystallized sulfide-based solid electrolyte is measured, and the resonance line observed at 70-120 ppm is converted into a Gaussian curve using a nonlinear least square method. It can measure by isolate | separating and calculating | requiring the area ratio of each curve.

As raw materials used for the production of the sulfide-based solid electrolyte, Li ₂ S (lithium sulfide), P ₂ S ₃ (phosphorus trisulfide), P ₂ S ₅ (phosphorus pentasulfide), SiS ₂ (silicon sulfide), Li ₄ SiO ₄ (lithium orthosilicate), Al ₂ S ₃ (aluminum sulfide), simple phosphorus (P), simple sulfur (S), silicon (Si), GeS ₂ (germanium sulfide), B ₂ S ₃ (trisulfide) Diarsenic), Li ₃ PO ₄ (lithium phosphate), Li ₄ GeO ₄ (lithium germanate), LiBO ₂ (lithium metaborate), LiAlO ₃ (lithium aluminate), etc. can be used, and Li ₂ S (sulfurized) Lithium) and P ₂ S ₅ (phosphorus pentasulfide) are preferably used.

A method for producing a sulfide-based solid electrolyte in the case where Li ₂ S (lithium sulfide) and P ₂ S ₅ (diphosphorus pentasulfide) are used as raw materials for the sulfide-based solid electrolyte will be described.
As the raw material lithium sulfide, those commercially available without particular limitation can be used. For example, JP-A-7-330312, JP-A-9-283156, JP-A 2010-163356, JP-A-2011. Lithium sulfide that can be produced by the method disclosed in Japanese Patent No. 084438 can be used.
In JP 2010-163356 A, lithium hydroxide and hydrogen sulfide are reacted at 70 ° C. to 300 ° C. in a hydrocarbon-based organic solvent to produce lithium hydrosulfide, and this reaction solution is then desulfurized. Lithium sulfide is synthesized by hydrogenation. Moreover, in the said Unexamined-Japanese-Patent No. 2011-084438, lithium hydroxide and hydrogen sulfide are made to react at 10 to 100 degreeC in a water solvent, lithium lithium sulfide is produced | generated, and this reaction liquid is then dehydrosulfurized. To synthesize lithium sulfide.

Lithium sulfide preferably has a total content of lithium salt of sulfur oxide of 0.15% by mass or less, more preferably a total content of lithium salt of sulfur oxide of 0.1% by mass or less. The lithium sulfide preferably has a lithium N-methylaminobutyrate content of 0.15% by mass or less, and more preferably a lithium N-methylaminobutyrate content of 0.1% by mass or less.
When the total content of the lithium salt of sulfur oxide is 0.15% by mass or less, the solid electrolyte obtained by the melt quenching method or the mechanical milling method can be made into a glassy electrolyte (fully amorphous). On the other hand, if the total content of the lithium salt of sulfur oxide exceeds 0.15% by mass, the obtained electrolyte may become a crystallized product from the beginning, and the ionic conductivity of this crystallized product is low. Further, even if this crystallized product is subjected to a heat treatment, the crystallized product is not changed, and there is a possibility that a sulfide-based solid electrolyte having high ion conductivity cannot be obtained.
In addition, when the content of lithium N-methylaminobutyrate is 0.15% by mass or less, a deteriorated product of lithium N-methylaminobutyrate does not deteriorate the cycle performance of the lithium ion battery.
By using lithium sulfide with reduced impurities in this way, a high ion conductive electrolyte can be obtained.

In the method for producing lithium sulfide described in JP-A-7-330312 and JP-A-9-283156, the obtained lithium sulfide contains a lithium salt of sulfur oxide and the like, and thus it is preferably purified. On the other hand, in the method for producing lithium sulfide described in JP 2010-163356 A, the obtained lithium sulfide can be used as it is without purification because it contains a very small amount of lithium oxide lithium salt or the like.
In the case of purifying lithium sulfide, a preferable purification method includes, for example, a purification method disclosed in International Publication WO2005 / 40039, and the obtained lithium sulfide is washed at a temperature of 100 ° C. or higher using an organic solvent. To be purified.

P ₂ S ₅ (phosphorus pentasulfide) used as a raw material for the sulfide-based solid electrolyte can be used without particular limitation as long as it is industrially produced and sold diphosphorus pentasulfide.

Sulfide-based solid electrolytes (sulfide-based glass solid electrolytes) are prepared by melting and quenching a mixture of lithium sulfide and phosphorous pentasulfide, a mechanical milling method (MM method), a slurry method in which raw materials are reacted in an organic solvent, etc. It can be produced by reacting.
The mixing ratio (molar ratio) of lithium sulfide and phosphorous pentasulfide is usually Li ₂ S: P ₂ S ₅ = 50: 50 to 80:20, preferably Li ₂ S: P ₂ S ₅ = 60: 40. 75: a 25, particularly preferably _{Li 2 S: P 2 S 5} = 68: 32~74: a 26 (molar ratio).

In the case of producing a sulfide-based glass solid electrolyte by a melt quenching method, for example, the melt quenching method disclosed in JP-A-6-279049 or WO2005 / 119706 may be carried out.
Specifically, P ₂ S ₅ and Li ₂ S are mixed in a predetermined amount in a mortar to form a pellet, and the pellet is placed in a carbon-coated quartz tube and vacuum-sealed. Then, it is made to react at a predetermined reaction temperature, put into ice and rapidly cooled to obtain a sulfide-based glass solid electrolyte.
The reaction temperature is preferably 400 ° C to 1000 ° C, more preferably 800 ° C to 900 ° C. Moreover, reaction time becomes like this. Preferably it is 0.1 to 12 hours, More preferably, it is 1 to 12 hours.
The quenching temperature of the reaction product is usually 10 ° C. or less, preferably 0 ° C. or less, and the cooling rate is usually about 1 to 10,000 K / sec, preferably 10 to 10,000 K / sec.

In the case of producing a sulfide-based glass solid electrolyte by a mechanical milling method, for example, the mechanical milling method disclosed in JP-A-11-134937, JP-A-2004-348972, or JP-A-2004-348993 may be performed.
Specifically, a predetermined amount of P ₂ S ₅ and Li ₂ S are mixed in a mortar, and the mixture is reacted for a predetermined time using, for example, various ball mills, etc., thereby obtaining a sulfide-based glass solid electrolyte.
In the MM method, the reaction can be performed at room temperature, and the glass solid electrolyte can be produced at room temperature. Therefore, there is an advantage that the raw material is not thermally decomposed and a glass solid electrolyte having a charged composition can be obtained. Further, the MM method has an advantage that the glass solid electrolyte can be made into fine powder simultaneously with the production of the glass solid electrolyte.
Note that the MM method is not limited to room temperature, and as disclosed in JP 2010-30889 A, the temperature in the mill during the mechanical milling process may be adjusted. It is preferable that the raw material be 60 ° C. or higher and 160 ° C. or lower during mechanical milling.

In the MM method, various types such as a rotating ball mill, a rolling ball mill, a vibrating ball mill, and a planetary ball mill can be used. As described in Japanese Patent Application Laid-Open No. 2010-90003, balls of different diameters are used for balls of a ball mill. You may mix and use.
As conditions for the MM method, for example, when a planetary ball mill is used, the rotational speed is set to several tens to several hundreds of revolutions / minute, and the treatment may be performed for 0.5 hours to 100 hours.
In addition to the above, as disclosed in JP2009-110920A and JP2009-2111950A, an organic solvent is added to a mixture of P ₂ S ₅ and Li ₂ S to form a slurry, and this slurry May be mechanically milled.

When the sulfide-based glass solid electrolyte is produced by a slurry method, for example, the slurry method disclosed in WO2004 / 093099 or WO2009 / 047977 may be carried out.
Specifically, a sulfide-based glass solid electrolyte is obtained by reacting a predetermined amount of P ₂ S ₅ particles and Li ₂ S particles in an organic solvent for a predetermined time. Moreover, a finer sulfide-based glass solid electrolyte can be obtained by further pulverizing the obtained slurry containing the solid electrolyte with a bead mill or the like.
The reaction temperature is preferably 20 ° C. or higher and 80 ° C. or lower, more preferably 20 ° C. or higher and 60 ° C. or lower. The reaction time is preferably 1 hour or longer and 16 hours or shorter, more preferably 2 hours or longer and 14 hours or shorter.

  When carrying out the slurry method, it is preferable to add an organic solvent to the raw materials lithium sulfide and diphosphorus pentasulfide to form a solution or slurry, and the raw materials (total amount) per liter of the organic solvent. Usually, 0.001 kg or more and 1 kg or less are added, preferably 0.005 kg or more and 0.5 kg or less are added, and particularly preferably 0.01 kg or more and 0.3 kg or more are added.

  The organic solvent to be added is not particularly limited, but is preferably an aprotic organic solvent, such as an aprotic organic solvent (for example, a hydrocarbon organic solvent), an aprotic polar organic compound (for example, an amide compound, a lactam). Compounds, urea compounds, organic sulfur compounds, cyclic organophosphorus compounds, etc.) can be used as a single solvent or as a mixed solvent thereof.

As the hydrocarbon organic solvent, a saturated hydrocarbon solvent, an unsaturated hydrocarbon solvent, or an aromatic hydrocarbon solvent can be used.
Examples of the saturated hydrocarbon solvent include hexane, pentane, 2-ethylhexane, heptane, decane, and cyclohexane; examples of the unsaturated hydrocarbon solvent include hexene, heptene, cyclohexene, and the like. Include toluene, xylene, decalin, 1,2,3,4-tetrahydronaphthalene and the like. Of these hydrocarbon organic solvents, toluene and xylene are particularly preferable.

When a hydrocarbon organic solvent is used in the slurry method, the hydrocarbon organic solvent is preferably dehydrated in advance, and specifically, a hydrocarbon organic solvent having a moisture content of 100 ppm by weight or less is preferable. A hydrocarbon organic solvent having a water content of 30 ppm by weight or less is particularly preferable.
In addition, you may add another solvent to a hydrocarbon type organic solvent as needed. Specific examples of other solvents that can be added include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; alcohols such as ethanol and butanol; esters such as ethyl acetate; halogenated carbonization such as dichloromethane and chlorobenzene. Hydrogen etc. are mentioned.

  In carrying out the slurry method, the reaction disclosed in Japanese Patent Application Laid-Open No. 2010-140893 may be performed by circulating the slurry containing the raw material between the bead mill and the reaction vessel. The raw material lithium sulfide may be pulverized in advance in order to advance the reaction efficiently as disclosed in JP-A-2011-136899, in order to increase the specific surface area of the raw material lithium sulfide, You may immerse in a polar solvent (for example, methanol, diethylcarnate, acetonitrile) whose solubility parameter is 9.0 or more for a predetermined time.

  The case where the sulfide-based glass solid electrolyte is produced by the melt quenching method, the mechanical milling method, or the slurry method has been described, but the production conditions such as temperature conditions, processing time, and charge when carrying out these methods are limited to the above. However, it can be adjusted appropriately according to the equipment used.

A sulfide-based crystallized glass solid electrolyte (sulfide-based glass ceramic solid electrolyte) can be produced by heat-treating the sulfide-based glass solid electrolyte at a predetermined temperature.
A method for producing a sulfide-based solid electrolyte (glass ceramic) is disclosed in, for example, JP-A-2005-228570, WO2007 / 065539, and JP-A-2002-109955.
Although described below a method of manufacturing a sulfide-based glass ceramic solid electrolyte, a sulfide-based glass solid electrolyte used in the preparation of the sulfide-based glass ceramic solid electrolyte material in Li 2 _{S (lithium} sulfide) and P ₂ S It is not limited to the sulfide type glass solid electrolyte obtained using ₅ (diphosphorus pentasulfide).

The heat treatment temperature for producing a sulfide-based glass ceramic solid electrolyte having a Li ₇ P ₃ S ₁₁ structure is preferably 180 ° C. or higher and 330 ° C. or lower, more preferably 200 ° C. or higher and 320 ° C. or lower, and particularly preferably It is 210 degreeC or more and 310 degrees C or less.
When the heat treatment temperature is less than 180 ° C., it may be difficult to obtain a crystallized glass with a high degree of crystallinity, and when the heat treatment temperature exceeds 330 ° C., there is a possibility that a crystallized glass with a low degree of crystallinity will be produced.

The heat treatment time for producing a sulfide-based glass ceramic solid electrolyte having a Li ₇ P ₃ S ₁₁ structure is preferably 3 hours or more and 240 hours or less when the heat treatment temperature is 180 ° C. or more and 210 ° C. or less, Especially preferably, it is 4 hours or more and 230 hours or less. In the case where the heat treatment temperature is higher than 210 ° C. and 330 ° C. or lower, it is preferably 0.1 hours or longer and 240 hours or shorter, more preferably 0.2 hours or longer and 235 hours or shorter, and even more preferably 0.3 hours or shorter. It is more than time and less than 230 hours.
When the heat treatment time is less than 0.1 hour, it may be difficult to obtain a crystallized glass with a high degree of crystallinity, and when the heat treatment time is over 240 hours, a crystallized glass with a low degree of crystallinity may be generated.

The heating conditions for producing a sulfide-based glass ceramic solid electrolyte having a Li ₇ PS ₆ structure, a Li ₄ P ₂ S ₆ structure, a Li ₃ PS ₄ structure and / or a Li ₄ SiS ₄ structure are known heating conditions. For example, the heating conditions disclosed in JP-A-2002-109955 can be applied.
Incidentally, sulfide-based glass ceramic solid electrolyte having the above-mentioned _Li 4 SiS ₄ structure, it is conceivable to produce, for example, from SiS ₂ and Li ₂ S.

A sulfide-based glass-ceramic solid electrolyte having a Li ₇ P ₃ S ₁₁ structure, and a sulfide-based glass having a Li ₇ PS ₆ structure, a Li ₄ P ₂ S ₆ structure, a Li ₃ PS ₄ structure, and / or a Li ₄ SiS ₄ structure. Whichever ceramic solid electrolyte is manufactured, the heat treatment is preferably performed in an environment having a dew point of −40 ° C. or lower, more preferably in an environment having a dew point of −60 ° C. or lower.
The pressure at the time of heating may be a normal pressure or a reduced pressure. The heating atmosphere may be air or an inert atmosphere.
In addition to the above, the heat treatment may be performed in a solvent disclosed in JP 2010-186744 A.

[Negative electrode mixture]
The mixing ratio (mass ratio) of the P-type doped Si powder and the inorganic solid electrolyte powder contained in the negative electrode mixture of the present invention is preferably P-type doped Si powder: inorganic solid electrolyte powder = 95: 5 to 30:70, Particularly preferred is P-type doped Si powder: inorganic solid electrolyte powder = 85: 15-40: 60.
When the ratio of the P-type doped Si powder to the inorganic solid electrolyte powder is 95 mass% or less, the lithium ion conduction path in the negative electrode mixture is increased, the reaction sites are increased, and the charge / discharge capacity is further increased. On the other hand, when the ratio of the P-type doped Si powder to the inorganic solid electrolyte powder is 30 mass% or more, the amount of the negative electrode in the negative electrode mixture is increased, and the charge / discharge capacity is further increased.

  The ratio of the average particle size of the P-type doped Si powder and the inorganic solid electrolyte powder in the negative electrode mixture is, for example, the average particle size of the P-type doped Si powder: The average particle size of the inorganic solid electrolyte powder is 10,000: 1 to 1: 10000. It is.

The negative electrode mixture can be produced by mixing a P-type doped Si powder, an inorganic solid electrolyte powder, and a conductive additive as necessary.
As a means for mixing the P-type doped Si powder, the inorganic solid electrolyte powder, the conductive auxiliary agent, etc., for example, suitable by dry mixing using a mortar, ball mill, bead mill, jet mill, planetary ball mill, vibration ball mill, sand mill, cutter mill In addition, after the raw materials are dispersed in an organic solvent, wet mixing using a mortar, ball mill, bead mill, planetary ball mill, vibration ball mill, sand mill, fill mix, and removal of the solvent is also preferably performed. it can.
The mixing means is not limited to the above.

[Negative electrode layer]
The negative electrode mixture of the present invention can be suitably used as a material for the negative electrode layer of an all-solid lithium ion battery. An all-solid lithium ion battery comprising a negative electrode layer containing the negative electrode mixture of the present invention is at least 0.4 C. Voltage abnormality during charging can be suppressed.
The negative electrode layer of the present invention may contain the negative electrode mixture of the present invention, and may further contain a conductive additive and / or a binder.

The conductive auxiliary agent only needs to have conductivity, and its electronic conductivity is preferably 1 × 10 ³ S / cm or more, more preferably 1 × 10 ⁵ S / cm or more.
Examples of the conductive aid include carbon materials and mixtures thereof.
Carbon materials include carbon and carbon materials other than carbon. Specific examples include carbon black such as ketjen black, acetylene black, denka black, thermal black, channel black; graphite, carbon fiber, activated carbon, etc. These may be used alone or in combination of two or more. Among these, acetylene black, denka black, and ketjen black having high electron conductivity are preferable.

The binder can improve battery moldability and bondability of particles in the battery, thereby improving charge / discharge capacity.
Examples of the binder include fluorine-containing resins such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and fluorine rubber; thermoplastic resins such as polypropylene and polyethylene; ethylene-propylene-dienemer (EPDM) and sulfonated EPDM. Natural butyl rubber (NBR) or the like can be used alone or as a mixture of two or more. In addition, an aqueous dispersion of cellulose or styrene butadiene rubber (SBR), which is an aqueous binder, can also be used.

[First All Solid Lithium Ion Battery of the Present Invention]
The 1st all-solid-state lithium ion battery of this invention is a battery which has the negative electrode layer of this invention, a solid electrolyte layer, and a positive electrode layer.
The 1st all-solid-state lithium ion battery of this invention should just be a laminated body on which the negative electrode layer, the solid electrolyte layer, and the positive electrode layer were laminated | stacked in this order, and may also have a collector.
Hereinafter, each layer which comprises the 1st all-solid-state lithium ion battery of this invention is demonstrated.

(1) Current collector A known current collector can be used as the current collector.
The current collector is a layer in which a layer made of a metal that reacts with a sulfide-based solid electrolyte, such as Au, Pt, Al, or Cu, is further coated with Au or the like.

(2) Solid electrolyte layer The solid electrolyte layer contains a solid electrolyte.
The solid electrolyte layer may contain a binder or the like, and the binder is as described above.
Examples of the solid electrolyte constituting the solid electrolyte layer include an inorganic solid electrolyte and a polymer solid electrolyte. The inorganic solid electrolyte is as described above, but the solid electrolyte contained in the negative electrode mixture and the solid electrolyte contained in the solid electrolyte layer may be the same or different. That is, it is not limited to the inorganic solid electrolyte particles contained in the negative electrode mixture of the present invention, and may be an inorganic solid electrolyte sheet or a polymer solid electrolyte.
Examples of the polymer solid electrolyte include materials used as polymer electrolytes such as fluororesin, polyethylene oxide, polyacrylonitrile, polyacrylate, derivatives thereof, and copolymers thereof disclosed in JP2010-262860A. It is done.
Examples of the fluororesin include resins containing as constituent units vinylidene fluoride (VdF), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), derivatives thereof, and the like. Homopolymers such as vinylidene (PVdF), polyhexafluoropropylene (PHFP), polytetrafluoroethylene (PTFE), and copolymers of VdF and HFP (hereinafter this copolymer is referred to as “P (VdF-HFP)”. Binary copolymers, ternary copolymers, etc. may be mentioned.

As described above, the shape of the solid electrolyte that is a raw material of the solid electrolyte layer may be either a particle shape or a sheet shape.
If it is a solid electrolyte particle, when forming a solid electrolyte layer, it can form by apply | coating the slurry containing a sulfide type solid electrolyte, for example, and can form simply. Moreover, if it is a solid electrolyte particle, an electrolyte layer can also be manufactured using an electrostatic method.

When the solid electrolyte layer is formed of a solid electrolyte powder, the solid electrolyte particles of the solid electrolyte layer are preferably fused together. The fusion means that a part of the solid electrolyte particles is dissolved and the dissolved part is integrated with other solid electrolyte particles.
Further, the solid electrolyte layer may be a solid electrolyte plate, and the plate solid electrolyte layer is formed by dissolving a part or all of the solid electrolyte particles and bonding them together to form a plate. Including the case.

(3) Positive electrode layer The positive electrode layer is formed of a positive electrode mixture composed of a positive electrode active material and a solid electrolyte. The positive electrode layer may further contain a conductive additive and / or a binder.
The solid electrolyte contained in the positive electrode layer can be the same as the solid electrolyte of the solid electrolyte layer, and the conductive auxiliary agent and binder of the positive electrode layer are the same as the conductive auxiliary agent and binder of the negative electrode layer of the present invention. Things can be used.

The positive electrode active material is a material capable of inserting and desorbing lithium ions, and those known as a positive electrode active part in the battery field can be used.
Specific examples of the positive electrode active material include V ₂ O ₅ , LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , Li (Ni _a Co _b Mn _c ) O ₂ (where 0 <a <1,0 <B <1, 0 <c <1, a + b + c = 1), LiNi _1-Y Co _{Y 2} O ₂ , LiCo _1-Y Mn _{Y 2} O ₂ , LiNi _1-Y Mn _{Y 2} O ₂ (where 0 ≦ Y < _{1), Li (Ni a Co} b Mn c) O 4 (0 <a <2,0 <b <2,0 <c <2, a + b + c = 2), LiMn 2-Z Ni Z O 4, LiMn 2- _Z CoZO ₄ (where 0 <Z <2), LiCoPO ₄ , LiFePO ₄ , Li _x CoO ₂ , Li _x NiO ₂ , Li _x Mn ₂ O ₄ , Li _x FePO ₄ , Li _x CoPO ₄ , Li _x Mn _{1 / 3} Ni _1/3 Co _1/3 O ₂ , Li _x Mn _1.5 Ni _0.5 O ₂ (X is 0.1 to 0.9); titanium sulfide (TiS ₂ ), molybdenum sulfide (MoS ₂ ), iron sulfide (FeS, FeS ₂ ), sulfide copper (CuS), nickel sulfide _(Ni 3 _{S 2)} sulfide positive electrode active material such (preferably _TiS 2); bismuth oxide _{(Bi 2 O} 3), lead-acid bismuth _{(Bi 2 Pb 2 O 5)} , oxide Oxide-based positive electrode active materials (preferably cobalt acid) such as copper (CuO), vanadium oxide (V ₆ O ₁₃ ), lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ) Lithium) and the like.
These positive electrode active materials can be used singly or as a mixture of two or more.

（式（Ａ）〜（Ｃ）において、Ｘはそれぞれ置換基であり、ｎ及びｍはそれぞれ独立に１〜２の整数であり、ｐ及びｑはそれぞれ独立に１〜４の整数である。
式（Ｄ）において、Ｚはそれぞれ−Ｓ−又は−ＮＨ−であり、ｎは繰返数２〜３００の整数である。）

（式中、ｎ、ｍは、それぞれ１以上の整数である。） In addition to the above, niobium selenide (NbSe ₃ ), organic disulfide compounds shown below, carbon sulfide compounds shown below, sulfur, indium metal, and the like can be used as the positive electrode active material.

(In Formulas (A) to (C), X is a substituent, n and m are each independently an integer of 1 to 2, and p and q are each independently an integer of 1 to 4.
In formula (D), Z is -S- or -NH-, respectively, and n is an integer of 2 to 300 repetitions. )

(In the formula, n and m are each an integer of 1 or more.)

(4) Negative electrode layer The negative electrode layer of a 1st all-solid-state lithium ion battery is a negative electrode layer containing the negative electrode compound material of this invention.
The negative electrode layer of the first all-solid-state lithium ion battery can be manufactured using the negative electrode mixture of the present invention. The negative electrode layer of the first all solid lithium ion battery may be a negative electrode layer made of the negative electrode mixture of the present invention.

[Second All Solid Lithium Ion Battery of the Present Invention]
The second all solid lithium battery of the present invention is a battery having a negative electrode layer containing a P-type doped Si powder, a solid electrolyte layer, and a positive electrode layer.
The second all solid lithium battery of the present invention is the same as the first all solid lithium ion battery of the present invention except that the negative electrode layer is a negative electrode layer containing P-type doped Si powder. Accordingly, since the same configuration is the same as described above, the description is omitted.
The negative electrode layer of the second all solid lithium ion battery is a negative electrode layer containing P-type doped Si powder. The negative electrode layer may include P-type doped Si powder. For example, when it includes a solid electrolyte, the negative electrode layer can include the same solid electrolyte as the solid electrolyte layer, and is not limited to the inorganic solid electrolyte powder. Further, when the negative electrode layer of the second all-solid-state lithium ion battery is composed of only P-type doped Si powder, the ratio of the active material in the negative electrode layer is maximized, so that the capacity is increased.

The thickness of each layer of the first all solid lithium ion battery and the second all solid lithium ion battery of the present invention (hereinafter, these may be collectively referred to as the all solid lithium ion battery of the present invention) is the thickness of the positive electrode layer. Is preferably 0.01 mm or more and 10 mm or less, the thickness of the solid electrolyte layer is preferably 0.001 mm or more and 1 mm or less, and the thickness of the negative electrode layer is preferably 0.01 mm or more and 10 mm or less.
When the all-solid-state lithium ion battery of this invention contains a collector, the thickness of the said collector is although it does not specifically limit, For example, they are 5 nm-10 mm, Preferably they are 30 nm-2 mm.
The all solid lithium ion battery of the present invention can be manufactured by a known method, for example, by a coating method or an electrostatic method (an electrostatic spray method, an electrostatic screen method, etc.).

Example 1
[Preparation of all solid lithium battery components]
(1) Preparation of solid electrolyte 0.6508 g (0.01417 mol) of high purity Li ₂ S produced according to the method disclosed in International Publication WO 2005/40039 and 1.3492 g (0) of P ₂ S ₅ (manufactured by Aldrich) .0060mol) was mixed well, and the mixed powder was put into an alumina pot and completely sealed. This pot was attached to a planetary ball mill. First, milling was performed at a low speed (85 rpm) for several minutes in order to sufficiently mix the starting materials. Thereafter, the rotational speed was gradually increased to 370 rpm, and mechanical milling was performed for 20 hours. When X-ray measurement was performed on the powder obtained by mechanical milling, it was confirmed that the powder was vitrified. Next, this vitrified powder was heat-treated at 300 ° C. for 2 hours to obtain an inorganic solid electrolyte powder.
When the ionic conductivity of the obtained inorganic solid electrolyte powder was measured by the alternating current impedance method (measurement frequency: 100 Hz to 15 MHz), it was 1.0 × 10 ⁻³ S / cm at room temperature.

(2) Preparation of P-type doped Si powder A P-type semiconductor Si wafer (made by SUMCO, 4 ″ P (100) 0-0.02) doped with 35 × 10 ¹⁷ B (boron atoms) per 1 cm ³ of Si powder. P-type doped Si powder was obtained by pulverizing with a nanojet mizer (NJ-50 manufactured by Aisin Nanotechnology).
When the average particle diameter of the obtained P-type Si powder was measured with a laser diffraction particle size distribution analyzer (manufactured by CILAS, type 1064), the D ₅₀ diameter was 4.2 μm.

The electronic conductivity of the green compact of the obtained P-type doped Si powder was 3.0 × 10 ⁻¹ S / cm.
The electronic conductivity of the Si powder compact was measured by the procedure shown in FIG. 50 mg of the obtained powder of P-type doped Si particles was placed in a ceramic cylindrical container 10 (diameter 6 mm, height 3 cm), and the upper and lower pressurizing means 30 and 32 in the longitudinal direction of the cylindrical container 10 at 141 MPa. The Si particle powder was pressed into a green compact. The resistance of this green compact was measured by the two-terminal method, the thickness of the green compact was also measured, and the electron conductivity was calculated using the following formula (1).
σ = L / (R · S) (1)
σ: electron conductivity [S / cm]
L: Green compact thickness [cm]
R: Resistance value [Ω]
S: Cross-sectional area of cylindrical container [cm ² ]

(3) Preparation of negative electrode mixture The boron atom P-type doped semiconductor Si powder (negative electrode active material) prepared in (2) above and the inorganic solid electrolyte powder prepared in (1) above were mixed at a mass ratio of 70:30. Thus, a negative electrode mixture was prepared.

(4) Preparation of positive electrode mixture After mixing 0.500 g of sulfur (Aldrich, purity 99.998%) and 0.214 g of carbon (Lion, Ketjen Black (KB) EC600JD) in a mortar, the mixture of sulfur carbon was sealed In a stainless steel container. This container was heat-treated in an electric furnace to prepare a sulfur carbon composite. In the heat treatment, the temperature was raised from room temperature to 150 ° C. at 10 ° C./min, held at 150 ° C. for 6 hours, further heated to 300 ° C. at 10 ° C./min, held for 2.75 hours, and then It was carried out by natural cooling.
The obtained sulfur carbon composite and the solid electrolyte powder prepared in (1) were mixed at a mass ratio of 50:50, and this mixture was mixed with a planetary ball mill (manufactured by Fritsch: model number P-7) in argon at room temperature (25 C.), a positive electrode mixture was obtained by mechanical milling at 370 rpm for 5 hours.

[Production and evaluation of all-solid-state lithium-ion batteries]
60 mg of the inorganic solid electrolyte powder prepared in (1) is put into a ceramic cylinder having a diameter of 10 mm, pressed to form an electrolyte layer (electrolyte sheet), and 6.9 mg of the positive electrode mixture prepared in (4). The positive electrode layer was formed by injection and pressure molding. 4.3 mg of the negative electrode mixture prepared in (3) was added from the side opposite to the positive electrode layer, and further pressure-molded to form a negative electrode layer. As a lithium source, 2.1 mg of lithium foil (made by Honjo Metal Co., Ltd.) was bonded to the negative electrode layer side and subjected to pressure molding to produce a lithium ion battery having a four-layer structure.

The prepared lithium ion battery was discharged at a charge / discharge rate of 0.1 C until the voltage reached 0.6 V, and then charged at a constant current (CC) at 0.1 C until the voltage reached 2.65 V. The battery was charged at a constant voltage (CV) until it reached 0.01C. After charging, the battery was discharged at 0.1 C until the voltage reached 0.6V.
After the next cycle, the charging rate that was 0.1 C is gradually increased to 0.2, 0.3, 0.4, and 0.5 C, and to what rate the voltage becomes unstable. It was evaluated whether the behavior (voltage abnormality) was resistant. Table 1 shows the limit charge rates that are resistant to voltage anomalies.

[Production and Evaluation of Half Cell Using Negative Electrode Compound]
60 mg of the inorganic solid electrolyte powder prepared in (1) is put into a ceramic cylinder having a diameter of 10 mm, pressed to form an electrolyte layer (electrolyte sheet), and 4.3 mg of the negative electrode mixture prepared in (3). The working electrode was formed by charging and pressure molding. From the opposite side of the working electrode, a LiIn alloy foil was bonded and pressure-molded as a reference electrode and a counter electrode, and a half cell having a three-layer structure was produced.
When the atomic ratio Li / In is 0.8 or less, the LiIn alloy can be used as a reference electrode because the Li desorption reaction potential is kept constant (0.62 V vs. Li / Li ⁺ ). Is possible.

The prepared half cell was 0.5 mA / cm ² and 0.01 Vvs. Li insertion was performed at a constant current (CC) up to Li / Li ⁺ , and Li insertion was performed at a constant voltage (CV) until the current reached 63.7 · A / cm ^{2 at} that voltage. Thereafter, at 0.5 mA / cm ² , 1.52 Vvs. Li was desorbed at a constant current (CC) to Li / Li ⁺ , and Li was inserted at a constant current (CC) at 0.5 mA / cm ² to evaluate the potential at which Li precipitation occurred. The results are shown in Table 1.

FIG. 2 is a diagram showing a potential-capacitance curve of the half cell when Li is inserted with a constant current (CC) at 0.5 mA / cm ² for the half cell of Example 1. FIG. As shown in FIG. 2, -0.75 Vvs. In ^{LiIn / Li + (-0.13Vvs.Li/Li +)} , the potential rise occurs, the reaction potential is occurring behavior becomes unstable. This behavior indicates that a Li precipitation reaction has occurred.

Comparative Example 1
Si simple substance powder in place of the P-type doped Si powder prepared in (2) (manufactured by Kojundo Chemical Laboratory Co., _Ltd., 99.9%, _{D 50} diameter: 4.5 [mu] m) other using in the same manner as in Example 1 Lithium ion batteries and half cells were manufactured and evaluated. The results are shown in Table 1.
In addition, the electronic conductivity of the green compact of the Si simple powder is 4.5 × 10 ⁻⁴ S / cm.

Comparative Example 2
A lithium ion battery and a half cell were produced and evaluated in the same manner as in Example 1 except that N-type doped Si powder was used instead of the P-type doped Si powder prepared in (2). The results are shown in Table 1.
The N-type doped Si powder is a nanojet of an N-type semiconductor Si wafer doped with 15 × 10 ¹⁷ Sb (antimony atoms) per ³ cm ³ Si powder (manufactured by SUMCO, 4 ″ N (100) 0-0.02). The average particle size of the N-type doped Si powder was measured with a laser diffraction particle size distribution measuring device (CILAS, type 1064), and the D ₅₀ size was obtained. The electron conductivity of the green compact of the N-type semiconductor Si particles was 1.8 × 10 ⁻¹ S / cm.

As shown in Table 1, in Example 1, the voltage abnormality was suppressed even when charged at a relatively high rate of 0.5 C, whereas in Comparative Examples 1 and 2, 0.3 C and 0.1 C, respectively. And it has voltage abnormality resistance only in the low rate region.
Further, as shown in Table 1, in Example 1, the potential at which Li deposition occurs was −0.12 Vvs. Li precipitation is suppressed to some extent even in the Li / Li ⁺ and Li precipitation potential regions, and Li is inserted into Si, whereas in Comparative Example 1, −0.10 Vvs. Li / Li ⁺ , -0.04 Vvs. Li precipitation occurs near Li / Li ⁺ and the Li precipitation potential. In this way, the Si material with N-type doping is more susceptible to voltage abnormality than Si alone, but Si with P-type doping has an electrochemical Li surface on the Si surface compared to Si alone. Resistant to precipitation of the metal, and also resistant to voltage abnormalities.

  The negative electrode mixture of the present invention can be used for a negative electrode layer of an all-solid-state lithium ion battery. The all-solid-state lithium ion battery of the present invention uses a portable information terminal, a portable electronic device, a small electric power storage device for home use, and a motor as a power source. It can be used as a battery for motorcycles, electric vehicles, hybrid electric vehicles and the like.

10 Cylindrical container 20 Si powder 30, 32 Compression means

Claims (10)

  A negative electrode mixture for a lithium ion battery, comprising Si powder doped in a P-type with a dopant and an inorganic solid electrolyte powder.   The negative electrode composite material according to claim 1, wherein the dopant includes one or more selected from B, Al, Ga, and In.   The negative electrode composite material according to claim 1 or 2, wherein an average particle diameter of the Si powder is 20 µm or less. The negative electrode composite material according to any one of claims 1 to 3, wherein an electronic conductivity of the green compact obtained by pressing the Si powder at 141 MPa is ^10-4 S / cm or more.   The negative electrode composite material according to claim 1, wherein the inorganic solid electrolyte powder is a sulfide-based solid electrolyte powder.   The negative electrode composite material according to claim 1, wherein a weight ratio of the Si powder to the inorganic solid electrolyte powder is 95: 5 to 30:70.   A negative electrode layer comprising the negative electrode mixture according to claim 1.   The negative electrode layer manufactured using the negative electrode compound material in any one of Claims 1-6.   An all-solid-state lithium ion battery comprising the negative electrode layer according to claim 7, a solid electrolyte layer, and a positive electrode layer.   An all-solid-state lithium ion battery including a negative electrode layer containing Si powder doped in a P-type with a dopant, a solid electrolyte layer, and a positive electrode layer.

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