WO2025004754A1 - ハロゲン化物固体電解質、正極材料、および電池 - Google Patents

ハロゲン化物固体電解質、正極材料、および電池 Download PDF

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WO2025004754A1
WO2025004754A1 PCT/JP2024/020795 JP2024020795W WO2025004754A1 WO 2025004754 A1 WO2025004754 A1 WO 2025004754A1 JP 2024020795 W JP2024020795 W JP 2024020795W WO 2025004754 A1 WO2025004754 A1 WO 2025004754A1
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solid electrolyte
halide solid
particles
compound
particle
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French (fr)
Japanese (ja)
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英一 古賀
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Panasonic Intellectual Property Management Co Ltd
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Panasonic Intellectual Property Management Co Ltd
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Priority to CN202480037827.1A priority Critical patent/CN121263855A/zh
Priority to JP2025529593A priority patent/JPWO2025004754A1/ja
Publication of WO2025004754A1 publication Critical patent/WO2025004754A1/ja
Priority to US19/429,500 priority patent/US20260121113A1/en
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • This disclosure relates to halide solid electrolytes, positive electrode materials, and batteries.
  • Patent Document 1 discloses a halide-based solid electrolyte material that contains Li, Al, Ti, and F.
  • Patent Document 2 discloses a halide-based solid electrolyte material as a solid electrolyte material that coats the surface of a positive electrode active material.
  • the objective of this disclosure is to provide a halide solid electrolyte with excellent ionic conductivity and reliability.
  • the halide solid electrolyte of the present disclosure is a halide solid electrolyte containing Li, Al, M, and X
  • the M is at least one element selected from the group consisting of metal elements (excluding Li and Al) and metalloid elements
  • X is at least one selected from the group consisting of F, Cl, Br, and I
  • the halide solid electrolyte is a first particle group consisting of first particles constituted by a compound A containing Al and the X; a second particle group consisting of second particles constituted of a compound B that does not contain Al and contains the M and the X; Including, In the first particle group, a coefficient of variation CV Al calculated by the following formula (A) using a standard deviation ⁇ Al of the ratio Al/X of the mass of Al to the mass of X and an average value A Al of the ratio Al /X is 10% or less, In the second particle group, a coefficient of variation CV M calculated by the following formula (B) using the standard deviation ⁇ M of the ratio M/
  • the present disclosure provides a halide solid electrolyte with excellent ionic conductivity and reliability.
  • FIG. 1 shows a schematic diagram of the microstructure of a halide solid electrolyte in a first embodiment of the present disclosure.
  • FIG. 2 is a flow diagram of a method for producing a halide solid electrolyte in the first embodiment of the present disclosure.
  • FIG. 3 is a flow diagram of a method for producing a solid electrolyte according to the first modification.
  • FIG. 4 shows a cross-sectional view of a battery 1000 according to a second embodiment.
  • FIG. 5 is a flow diagram of the method for producing the halide solid electrolyte of Example 1.
  • the halide solid electrolyte in the first embodiment of the present disclosure contains Li, Al, M, and X.
  • M is at least one element selected from the group consisting of metal elements (excluding Li and Al) and metalloid elements
  • X is at least one element selected from the group consisting of F, Cl, Br, and I.
  • the halide solid electrolyte in this embodiment includes a first particle group made of first particles composed of compound A containing Al and X, and a second particle group made of second particles composed of compound B not containing Al and containing M and X.
  • the coefficient of variation CV Al calculated by the following formula (A) using the standard deviation ⁇ Al of the ratio Al/X of the mass of Al to the mass of X and the average value A Al of the ratio Al/X is 10% or less.
  • the coefficient of variation CV M calculated by the following formula (B) using the standard deviation ⁇ M of the ratio M/X of the mass of M to the mass of X and the average value A M of the ratio M/X is 20% or less.
  • the mass of M is the total mass of all the elements contained as M.
  • the halide solid electrolyte of this embodiment has excellent ionic conductivity due to the above-mentioned configuration. Furthermore, the halide solid electrolyte of this embodiment has excellent stability (e.g., heat resistance and atmospheric environment resistance) and can have high reliability. Therefore, the halide solid electrolyte of this embodiment can have excellent ionic conductivity and reliability. For example, by having a coefficient of variation CV Al of 10% or less and a coefficient of variation CV M of 20% or less, the halide solid electrolyte of this embodiment can achieve a high ionic conductivity of, for example, 1 ⁇ S/cm or more.
  • Identification of the first and second particles contained in the halide solid electrolyte i.e., identification of whether Al is included or not
  • the mass of Al and X in the first particles, and the mass of M and X in the second particles can be determined by elemental analysis using energy dispersive X-ray spectroscopy (EDS) or electron probe microanalyzer (EPMA).
  • EDS energy dispersive X-ray spectroscopy
  • EPMA electron probe microanalyzer
  • a cross section of the compact is formed by an ion polisher or the like, and a plurality of spots having a spot diameter (diameter) of, for example, 1 ⁇ m are set on the cross section.
  • identification of the first and second particles, the mass of Al and X in the first particles, and the mass of M and X in the second particles may be determined by, for example, point analysis using EPMA.
  • the ratio of the mass of Al to the mass of X, Al/X is determined from the results of elemental analysis.
  • the ratio of the mass of M to the mass of X, M/X is determined from the results of elemental analysis.
  • the results of the ratio Al/X of any 20 spots identified as the first particles are used to determine the standard deviation ⁇ Al and average value A Al of the ratio Al/X, and the coefficient of variation CV Al is calculated from these values using the above formula (A).
  • the results of the ratio M/X of any 20 spots identified as the second particles are used to determine the standard deviation ⁇ M and average value A M of the ratio M/X, and the coefficient of variation CV M is calculated from these values using the above formula (B).
  • the coefficient of variation CV Al may be, for example, 9% or less, 8% or less, or 7% or less.
  • the coefficient of variation CV M may be, for example, 18% or less, 15% or less, or 12% or less.
  • the ratio Al/X may be equal to or greater than (average value A Al - 3 ⁇ standard deviation ⁇ Al ) and equal to or less than (average value A Al + 3 ⁇ standard deviation ⁇ Al ). That is, in the halide solid electrolyte of the present embodiment, the relational expression A Al - 3 ⁇ Al ⁇ ratio Al/X ⁇ A Al + 3 ⁇ Al may be satisfied. This reduces particles having a composition with low ionic conductivity, and therefore a halide solid electrolyte with higher ionic conductivity (for example, 1.0 ⁇ S/cm or more, or 3.0 ⁇ S/cm or more) can be obtained.
  • the ratio M/X may be equal to or greater than (average value A M - 3 ⁇ standard deviation ⁇ M ) and equal to or less than (average value A M + 3 ⁇ standard deviation ⁇ M ). That is, in the halide solid electrolyte of the present embodiment, the relational expression A M - 3 ⁇ M ⁇ ratio M/X ⁇ A M + 3 ⁇ M may be satisfied. This reduces particles having a composition with low ionic conductivity, making it possible to obtain a halide solid electrolyte with higher ionic conductivity (for example, 1.0 ⁇ S/cm or more, or 3.0 ⁇ S/cm or more).
  • the ratio Al/X may be equal to or greater than (average value A Al - 3 ⁇ standard deviation ⁇ Al ) and equal to or less than (average value A Al + 3 ⁇ standard deviation ⁇ Al ), and the ratio M/X may be equal to or greater than (average value A M - 3 ⁇ standard deviation ⁇ M ) and equal to or less than (average value A M + 3 ⁇ standard deviation ⁇ M ).
  • the first and second particles, compound A and compound B, and the method for producing the halide solid electrolyte are described in more detail below.
  • FIG. 1 shows a schematic diagram of the microstructure of the halide solid electrolyte in this embodiment.
  • the halide solid electrolyte in this embodiment includes a first particle 10 and a second particle 20.
  • the halide solid electrolyte in this embodiment is composed of an aggregate of a plurality of particles including a plurality of first particles 10 (i.e., a first particle group) and a plurality of second particles 20 (i.e., a second particle group).
  • the first particle 10 is composed of a compound A containing Al and X.
  • the second particle 20 is composed of a compound B containing M and X without containing Al.
  • the second particle 20 is hatched in order to distinguish the first particle 10 from the second particle 20.
  • the halide solid electrolyte in this embodiment may be in a powder state or may be a pressed powder.
  • the halide solid electrolyte in this embodiment may be, for example, a compact formed of the first particles 10 and the second particles 20.
  • the halide solid electrolyte in this embodiment is, for example, a compact formed of the first particles 10 and the second particles 20
  • the halide solid electrolyte in this embodiment can realize a solid electrolyte layer of a battery or a coating layer of active material particles that has excellent ionic conductivity and reliability.
  • the first particles 10 and the second particles 20 may each have an average particle diameter of, for example, 0.1 ⁇ m or more and 10 ⁇ m or less.
  • the first particles 10 and the second particles 20 may each have a BET specific surface area of, for example, 0.2 m 2 /g or more and 20 m 2 /g or less.
  • the particle shape of the first particles 10 and the second particles 20 may be any shape, such as spherical, acicular, or scaly.
  • At least one particle selected from the group consisting of the first particle 10 and the second particle 20 may contain an amorphous phase.
  • the amorphous phase includes not only an amorphous phase, but also a phase with disordered crystallinity, in other words, a distorted crystal phase.
  • This configuration makes it possible to obtain a halide solid electrolyte that has both high ionic conductivity (e.g., 1.0 ⁇ S/cm or more) and low electronic conductivity (e.g., 0.01 ⁇ S/cm or less).
  • the amorphous phase portion is generally softer and more easily deformed than the highly crystalline crystalline phase.
  • the halide solid electrolyte having the above configuration is likely to form an interface where the particles are in close contact with each other, and is likely to be densified and thinned, and further, an improvement in ionic conductivity can be expected. Therefore, when the halide solid electrolyte having the above configuration is used in, for example, a solid electrolyte layer of a battery, the solid electrolyte layer can be thinned, or it can be suitably used in the coating layer of the active material particles.
  • the volume of the amorphous phase contained in the second particle 20 may be larger than the volume of the amorphous phase contained in the first particle 10.
  • This configuration can further improve ionic conductivity and reliability.
  • the above configuration makes the halide solid electrolyte softer and easier to deform, improving the adhesion between particles and reducing the gaps between particles. Therefore, the halide solid electrolyte having the above configuration can be densified when made into a pressed powder.
  • the solid electrolyte layer can be densified, and it can be suitably used as a coating layer for active material particles.
  • the amorphous phase contained in the first particles 10 may have a higher ionic conductivity than the amorphous phase contained in the second particles 20. With this configuration, the softer second particles 20 can bond the first particles 10, which have a higher ionic conductivity, and therefore high ionic conductivity can be obtained.
  • the amorphous phase may have lower electronic conductivity than the portions of the first particle 10 and the second particle 20 other than the amorphous phase.
  • the amorphous phase has lower electronic conductivity (e.g., 0.01 ⁇ S/cm or less) than the portions of the first particle 10 and the second particle 20 other than the amorphous phase, a halide solid electrolyte with superior ionic conductivity is obtained.
  • the particle surface layer may contain more of the amorphous phase than the particle interior.
  • an amorphous phase is generally softer than a crystalline phase with high crystallinity.
  • the bonding i.e., the binding
  • the halide solid electrolyte in this embodiment can achieve a dense powder structure and improved mechanical strength of the powder compact.
  • the region containing the amorphous phase may have a higher ionic conductivity and a lower electronic conductivity than the region not containing the amorphous phase (e.g., the inside of the particle).
  • the ionic conductivity of the region containing the amorphous phase may be, for example, 1 ⁇ S/cm or more.
  • the electronic conductivity of the region containing the amorphous phase may be, for example, 0.01 ⁇ S/cm or less.
  • a halide solid electrolyte containing the first particle 10 and the second particle 20 having such a configuration can form a solid electrolyte that is dense in the powder compact, has high ionic conductivity, and has low electronic conductivity, and is useful for improving the performance of batteries.
  • the amorphous region contained in the particle surface layer becomes a bonding interface between particles in the powder compact, and can form a network formed three-dimensionally in a mesh shape with high ionic conductivity (e.g., 1 ⁇ S/cm or more) and low electronic conductivity (e.g., 0.01 ⁇ S/cm or less).
  • Such differences in crystallinity between the inside of a particle, the surface of a particle, and the interface of a particle can be observed with a high-resolution transmission electron microscope (TEM) as images of highly regular regions of the lattice image and regions of disordered lattice images.
  • TEM transmission electron microscope
  • the mechanical strength and electrical properties within the particle can be evaluated by mechanical strength measurements such as micro Vickers, or by a nanoprober used in semiconductor evaluation.
  • the amorphous nature that is primarily formed on the particle surface is formed from the particle surface where the impact acts directly, by mechanochemical treatment using a ball mill with general zirconia balls.
  • the surface becomes amorphous before the interior of the particle, making it easier for the particles to bond together and reducing friction between particles during the pressure application process.
  • the mechanochemical treatment method and the zirconia balls that are the grinding media for the grinding media, and any material that can be made amorphous, such as alumina, that is hard and less susceptible to contamination, can be used.
  • first particles 10 and the second particles 20, which have different compositions, are uniformly dispersed.
  • the dispersibility of the first particles 10 and the second particles 20 can be observed, for example, by elemental analysis (area analysis or point analysis) using EDS or EPMA on the cross section of the powder compact using an ion polisher, etc.
  • the first particle 10 is composed of compound A
  • the second particle 20 is composed of compound B.
  • Compound A contains Al and X.
  • Compound B does not contain Al, and contains M and X.
  • Compound A may be represented by the following composition formula (1), and compound B may be represented by the following composition formula (2).
  • Composition formula (1) Li 3 (Al 1-y1 M y1 )X 6
  • Composition formula (2) Li 2 MX 6 In the composition formula (1), y1 satisfies 0 ⁇ y1 ⁇ 1.
  • the average composition of compound A constituting each first particle 10 may be represented by the above composition formula (1), or compound A in all first particles 10 may be represented by the above composition formula (1).
  • the average composition of compound A constituting first particles 10 can be determined using the results of elemental analysis by EDS or EPMA when identifying the above-mentioned first particles and second particles.
  • the average composition of compound A in first particles 10 can be determined from the results of elemental analysis for any 20 spots identified as first particles 10.
  • the average composition of compound B constituting each second particle 20 may be represented by the above composition formula (2), or compound B in all second particles 20 may be represented by the above composition formula (2).
  • the average composition of compound B constituting second particles 20 can be determined using the results of elemental analysis by EDS or EPMA when identifying the above-mentioned first particles and second particles.
  • the average composition of compound B in second particles 20 can be determined from the results of elemental analysis for any 20 spots identified as second particles 20.
  • a halide solid electrolyte with improved reliability can be obtained by using a mixed structure of compound A and compound B, which have a high Li ion content and high ionic conductivity.
  • the two compounds A and B which have different compositions, are different from each other in mechanical properties, thermal expansion, heat resistance, etc. Furthermore, the temperature characteristic dependencies of these properties do not match. Therefore, when the halide solid electrolyte of this embodiment is made into a compact, particles with different properties such as mechanical properties, thermal expansion, and heat resistance are dispersed in the compact structure, and critical destruction and deterioration are suppressed. This is presumably because the presence of particles with different properties in a dispersed state makes damage sporadic and does not lead to destruction all at once, making it difficult for property deterioration to become apparent. Therefore, the halide solid electrolyte of this embodiment, which includes the two compounds A and B, which have different compositions, has high ionic conductivity, while further improving bending resistance, thermal shock resistance, and heat resistance, and provides high reliability.
  • the halide solid electrolyte in this embodiment includes a first particle 10 composed of compound A represented by composition formula (1) and a second particle 20 composed of compound B represented by composition formula (2)
  • the halide solid electrolyte in this embodiment can also be represented by the following composition formula (6).
  • Composition formula (6) xLi 3 (Al 1-y1 M y1 )X 6 -(1-x)Li 2 MX 6 (0 ⁇ x ⁇ 1)
  • x satisfies 0 ⁇ x ⁇ 1.
  • Compound A may be represented by the following composition formula (3).
  • Composition formula (3) Li 3 AlX 6
  • a halide solid electrolyte with improved reliability can be obtained by using a mixed structure of compound A and compound B, which have a high Li ion content and high ionic conductivity.
  • the first particle group may include particles including a first crystal phase represented by the following composition formula (4) and a second crystal phase represented by the following composition formula (5).
  • Composition formula (4) Li 3 (Al 1-y2 M y2 )X 6
  • Composition formula (5) Li 2 MX 6 In the composition formula (4), y2 satisfies 0 ⁇ y2 ⁇ 1.
  • the first crystal phase and the second crystal phase are contained in one particle.
  • a halide solid electrolyte with improved reliability can be obtained.
  • the molar ratio of the first crystal phase to the sum of the first crystal phase and the second crystal phase may be 0.05 or more and 0.95 or less.
  • X may contain F.
  • a halide solid electrolyte with excellent stability e.g., electrochemical stability and heat resistance
  • electrochemical stability and heat resistance e.g., electrochemical stability and heat resistance
  • This suppresses characteristic fluctuations during the manufacturing process, making it possible to obtain a battery with good performance and excellent reliability.
  • the ion conductivity and particle shape e.g., BET specific surface area, etc.
  • M may contain Ti. This configuration makes it possible to obtain a halide solid electrolyte with higher ionic conductivity. Furthermore, by including Ti, the solid-phase reaction temperature can be lowered (for example, to 750°C or less), that is, the reaction can be accelerated. Therefore, a homogeneous halide solid electrolyte with excellent ionic conductivity can be obtained.
  • M may contain Ti, and y1 may satisfy 0 ⁇ y1 ⁇ 0.3. This configuration makes it possible to obtain a halide solid electrolyte with higher ionic conductivity.
  • M may contain Ti, and y2 may satisfy 0 ⁇ y2 ⁇ 0.3. This configuration makes it possible to obtain a halide solid electrolyte with higher ionic conductivity.
  • Compound A represented by composition formula (3) may have a monoclinic crystal structure. This configuration makes it possible to obtain a halide solid electrolyte with higher ionic conductivity (e.g., 1.0 ⁇ S/cm or more).
  • the first crystal phase may have an orthorhombic crystal structure.
  • M may contain Ti.
  • a halide solid electrolyte having an even higher ionic conductivity e.g., 6.0 ⁇ S/cm or more.
  • the halide solid electrolyte compact in this embodiment can be used, for example, as a solid electrolyte layer of a battery, a coating layer that coats an active material of a battery, and a composite material for an electrode layer.
  • the halide solid electrolyte in this embodiment can form a compact with high packing (for example, a relative density of 95% or more). This allows a compact with high ionic conductivity and excellent mechanical performance (for example, high bending strength and high impact resistance) to be obtained.
  • the relative density of the solid electrolyte for example, 90% or less
  • the heat capacity is reduced, and the thermal shock resistance can be improved.
  • the density of such a compact of the solid electrolyte can be controlled, for example, by the pressure at which the compact is formed. Since the halide solid electrolyte in this embodiment is a material with excellent interparticle adhesion, a wide density range can be controlled according to the intended use.
  • the active material when the solid electrolyte of this embodiment is used for the coating layer of the active material, the active material can be densified by increasing the shear stress when coating the active material.
  • the shear stress is, for example, 29.4 MPa or more and 980 MPa or less.
  • the first particle 10 and/or the second particle 20 are softened by including an amorphous phase, and the binding between the particles can be improved.
  • the effect of suppressing the destruction of the active material particles due to the stress during coating is also obtained, and the effect of suppressing the deterioration of characteristics due to the destruction of the active material particles is also obtained.
  • the friction between the particles is also reduced, the heat generation between the particles during pressure or coating is also suppressed. Therefore, the denaturation of the solid electrolyte and the active material due to heat can be suppressed, and the deterioration of characteristics and the change in particle shape can be suppressed.
  • the melting point of the compound A represented by the composition formula (1) is, for example, 750°C or more and 800°C or less in air.
  • the melting point of the compound B represented by the composition formula (2) is, for example, around 700°C in air.
  • the compound B having a lower melting point tends to be softer.
  • the amorphization of the compound B tends to proceed easily. Therefore, in this case, the amorphous phase of the particle surface layer of the compound B is large, or the second particle 20 composed of the compound B has many amorphized particles.
  • a solid electrolyte obtained by mixing the first particle 10 composed of the compound A and the second particle 20 composed of the compound B and subjecting them to a mechanochemical treatment the amorphization of the particle surface of the second particle 20 proceeds more, resulting in an effect of improving the binding property of the bonding interface with the particle.
  • the effect of the soft compound B particles preferentially deforming and filling the gaps between the particles of compound A can be obtained.
  • a solid electrolyte that is dense and has excellent mechanical performance can be obtained.
  • a solid electrolyte that is dense and less prone to defects can be formed.
  • a powder of Li 3 AlF 6 with a compact density of 1.942 g/cm 3 and a powder of Li 2 TiF 6 in a molar ratio of, for example, 75:25 the density is increased to 1.988 g/cm 3 .
  • the halide solid electrolyte of this embodiment can be produced, for example, by the following method.
  • FIG. 2 is a flow diagram of a method for producing a halide solid electrolyte in an embodiment of the present disclosure. The method for producing a halide solid electrolyte in this embodiment will be described below with reference to FIG. 2.
  • First particles 10 made of compound A are prepared by synthesizing a plurality of badges whose average composition is the composition of the target compound A, for example, composition formula (1), and whose Al components differ slightly from each other.
  • second particles 20 made of compound B are prepared by synthesizing a plurality of badges whose average composition is the composition of the target compound B, for example, composition formula (2), and whose M components differ slightly from each other.
  • the obtained first particles 10 and second particles 20 are mixed in a predetermined ratio, and the halide solid electrolyte of this embodiment can be synthesized. Note that the synthesis method is not limited to this, and it is sufficient that the solid electrolyte of this embodiment is ultimately synthesized, and the synthesis route is not limited to this embodiment.
  • An example of a specific method for producing the first particle 10 is as follows.
  • a plurality of badges in which the Al component is changed slightly are pre-synthesized so that the average composition is the composition of the target compound A.
  • the average composition of the result of synthesizing the plurality of pre-synthesized badges is the composition of the target compound A.
  • the badge Al is a mixture of starting materials so that it has a composition in which Al is -a% from the composition of the target compound A, that is, the mixing ratio of the starting materials is a ratio in which Al is reduced by a% in molar ratio from the amount of Al charged when synthesizing the target composition.
  • the badge A2 is a mixture of starting materials at a ratio that results in the composition of the target compound A. That is, the change in Al from the target composition in the badge A2 is ⁇ 0%.
  • the badge A3 is a mixture of starting materials so that it has a composition in which Al is +a% from the composition of the target compound A, that is, the mixing ratio of the starting materials is a ratio in which the molar ratio of Al is increased by a% from the amount of Al charged when synthesizing the target composition. a can be adjusted, for example, in the range of 0.001% or more and 10% or less.
  • the starting materials that are the sources of Li, Al, and M are charged at each ratio, and preliminary synthesis A (synthesis of badges A1, A2, and A3) is performed, for example, by mechanochemical synthesis.
  • the form of the starting materials may be, for example, halides such as fluorides (for example, LiF, AlF 3 , fluorides of M), but is not limited to halides such as fluorides.
  • any form of raw material such as oxide, carbonate, or fluoride oxide can be used as long as it can synthesize the solid electrolyte in this embodiment.
  • the starting materials may contain auxiliary components (ie, Nb and Ga components), which can promote the synthesis reaction (for example, LiF+AlF 3 ⁇ Li 3 AlF 6 ).
  • This synthesis step A produces a powder whose average composition is the composition of the target compound A.
  • This powder corresponds to the first particles 10.
  • the particle size of the powder may be any size that is easy to handle during the manufacturing process, and may be, for example, an average particle size of 0.5 ⁇ m or more and 3.0 ⁇ m or less. Note that, although an example of synthesis using three badges A1, A2, and A3 has been given, this is not limiting, and three or more badges may be used.
  • An example of a specific method for producing the second particles 20 is as follows.
  • a plurality of badges in which the M component is slightly changed are pre-synthesized so that the average composition is the composition of the target compound B.
  • the average composition of the product of synthesis of the plurality of pre-synthesized badges is the composition of the target compound B.
  • three badges B1, B2, and B3 in which the M component is slightly different from each other are prepared.
  • Badge B1 is a product in which starting materials are mixed so that the composition of the target compound A is -b% M, that is, the mixing ratio of the starting materials is a ratio in which b% M is reduced in molar ratio from the amount of M charged when synthesizing the target composition.
  • Badge B2 is a product in which starting materials are mixed at a ratio that results in the composition of the target compound B. That is, the change in M from the target composition of badge B2 is ⁇ 0%.
  • the badge B3 is a mixture of starting materials so that the composition of the target compound B is such that M is +b%, that is, the mixing ratio of the starting materials is such that b%M is increased by a molar ratio from the amount of M charged when synthesizing the target composition. b can be adjusted, for example, in the range of 0.001% or more and 15% or less.
  • the starting materials that are the sources of Li and M are charged at each ratio, and preliminary synthesis B (synthesis of badges B1, B2, and B3) is performed, for example, by mechanochemical synthesis.
  • the form of the starting materials may be, for example, each fluoride (for example, LiF, fluoride of M), but is not limited to fluoride.
  • any form of raw material such as oxide, carbonate, or fluoride oxide can be used as long as it can synthesize the solid electrolyte in this embodiment.
  • the starting materials may contain auxiliary components (ie, Nb and Ga components), which can promote the synthesis reaction (for example, LiF+AlF 3 ⁇ Li 3 AlF 6 ).
  • This synthesis step B produces a powder whose average composition is the composition of the target compound A.
  • This powder corresponds to the first particles 10.
  • the particle size of the powder may be any size that is easy to handle during the manufacturing process, and may be, for example, an average particle size of 0.5 ⁇ m or more and 3.0 ⁇ m or less. Note that, although an example of synthesis using three badges B1, B2, and B3 has been given, this is not limiting, and three or more badges may be used.
  • the mixture is placed in a planetary ball mill (capacity 300 mL) together with zirconia balls (diameter 0.5 mm or more and 3 mm or less, 100 g or more and 400 g or less), and a dry mechanochemical treatment (for example, 20 hours or more and 60 hours or less) is performed as the main synthesis process to synthesize a solid electrolyte containing compositional variations of Al and M, including amorphous nature.
  • a dry mechanochemical treatment for example, 20 hours or more and 60 hours or less
  • the auxiliary component (Nb, Ga component (e.g., NbF5 , GaF3 )) may be included in this synthesis process.
  • the auxiliary component may be divided and included during the synthesis of compound A, the synthesis of compound B, and the main mixing of compound A (i.e., the first particle 10) and compound B (i.e., the second particle 20).
  • the auxiliary component can be uniformly dispersed in the solid electrolyte.
  • the auxiliary component (Nb, Ga) has an effect of promoting a solid-phase reaction (a reaction to synthesize compound A and compound B from the starting material).
  • the auxiliary component should have a fine particle form so as not to generate an unnecessary precipitated phase.
  • the auxiliary component be a particle smaller than the starting material (e.g., LiF, AlF3 , and TiF4 ) (e.g., an average particle diameter of 0.1 ⁇ m or more and 1 ⁇ m or less).
  • a fluoride was used as the starting material, but a halide corresponding to the halogen element contained in X can be used.
  • the number of divided badges is not limited to three, but may be two or more, or may be four or more.
  • dry mixing and mechanochemical processing since powder does not have the fluidity of liquids, by making the number of divided badges multiple (and increasing it), it becomes easier to synthesize a limited composition range or a homogeneous solid electrolyte.
  • the number of divided badges may be set in consideration of productivity.
  • the number of divided badges may be different for compound A and compound B.
  • the solid electrolyte according to this embodiment can be synthesized.
  • homogenization may be difficult, and due to compositional unevenness, unnecessary precipitated phases are likely to be generated, resulting in large compositional fluctuations.
  • the diameter of the zirconia ball can be any size to adjust the amount of powder and the grinding force.
  • composition A which includes a compositional difference
  • compound B is not limited to a ball mill, and may be wet mixing using, for example, a V blender or a disper mill using a solvent such as ethanol.
  • the dispersion state and compositional difference (Al and Ti) of compound A and compound B in the solid electrolyte can be evaluated by elemental analysis (area analysis or point analysis) using, for example, EPMA or EDS.
  • a halide such as fluoride was used as the starting material.
  • an oxide may be used as the starting material, and a precursor of the oxide of compound A and a precursor of the oxide of compound B may be halogenated (fluorinated).
  • fluorinated fluorinated
  • Modification 1 is a flow diagram of a method for producing a solid electrolyte according to Modification 1.
  • Modification 1 differs in that compound A and compound B having different compositions are synthesized from chemically pure oxide and carbonate powders of Li2CO3 , TiO2 , and Al2O3 as starting materials to synthesize oxide precursors (compound A and compound B ), which are then mixed with NH4F powder and heat-treated to fluorinate the oxide precursors, thereby synthesizing a solid electrolyte.
  • the starting materials are weighed out in a normal atmospheric environment on a 30 g scale to achieve the respective ratios, and then wet mixed and ground (20 h) using a 600 ml ball mill (using ⁇ 1 mm zirconia balls and pure water (60 ml)), and then air dried in a dryer (200°C for 20 h) to obtain the precursor powders of pre-synthesized B1, B2, B3, B4, and B5.
  • the obtained pre-synthesized B1, B2, B3, B4, and B5 powders are dry mixed (mortar and pestle) to obtain the precursor powder of compound B.
  • the precursor powders of the above compound A preliminary synthesis A1, A2, A3, A4, and A5 and the precursor powders of compound B (preliminary synthesis B1, B2, B3, B4, and B5) were dry-mixed in a specified ratio using a mortar and pestle for about 10 minutes to obtain a precursor mixed powder of compound A and compound B.
  • a specified amount of NH4F powder as a fluoride source and the precursor mixed powder of compound A and compound B were weighed out in a specified ratio to a total amount of 30 g, and dry-mixed for about 10 minutes using a mortar and pestle.
  • the powder mixed with NH 4 F (NH 4 F + compound A precursor + compound B precursor) is placed in a high-purity (SSA-H) alumina crucible and converted into a fluoride by heat treatment at 330° C. for 5 hours in a nitrogen atmosphere using a general electric furnace. Thereafter, the obtained fluoride is subjected to mechanochemical treatment in the same manner as in the embodiment.
  • SSA-H high-purity alumina crucible
  • the diameter of the zirconia ball can be any size to adjust the amount of powder and the crushing force.
  • the precursor may be a fluoride oxide (e.g., TiF2O ).
  • the fluorination method is not limited to the above method, and fluorination may be performed by generating fluorine gas by heat-treating a fluorination source and contacting the fluorine gas with the object to be fluorinated.
  • the precursor mixed powder of compound A and compound B is on a fine mesh such as a nickel net, and the fluoride source (ammonium fluoride) is below it, and they are not in direct contact with each other.
  • fluoride source ammonium fluoride
  • Any fluoride source can be used as long as it is thermally decomposed.
  • the fluoride source may contain inorganic residues (for example, CuF2 , which emits F as gas by heating). It is preferable to perform heat treatment in a nitrogen atmosphere or a reducing atmosphere so that the nickel net does not oxidize, but heat treatment can be performed in the air several times.
  • the battery according to the second embodiment includes a positive electrode, an electrolyte layer, and a negative electrode.
  • the electrolyte layer is provided between the positive electrode and the negative electrode.
  • At least one selected from the group consisting of the positive electrode, the electrolyte layer, and the negative electrode contains the halide solid electrolyte according to the first embodiment.
  • the battery according to the second embodiment has excellent charge/discharge characteristics because it contains the halide solid electrolyte according to the first embodiment.
  • FIG. 4 shows a cross-sectional view of a battery 1000 according to the second embodiment.
  • the battery 1000 according to the second embodiment includes a positive electrode 201, an electrolyte layer 202, and a negative electrode 203.
  • the electrolyte layer 202 is provided between the positive electrode 201 and the negative electrode 203.
  • the positive electrode 201 may include a positive electrode material including a halide solid electrolyte according to the first embodiment.
  • the positive electrode 201 contains a positive electrode active material 204 and a solid electrolyte 100.
  • the electrolyte layer 202 contains an electrolyte material.
  • the negative electrode 203 contains a negative electrode active material 205 and a solid electrolyte 100.
  • the solid electrolyte 100 includes, for example, the halide solid electrolyte according to the first embodiment.
  • the solid electrolyte 100 may be particles containing the halide solid electrolyte according to the first embodiment as a main component. Particles containing the halide solid electrolyte according to the first embodiment as a main component refer to particles in which the component contained most abundantly in terms of molar ratio is the halide solid electrolyte according to the first embodiment.
  • the solid electrolyte 100 may be particles made of the halide solid electrolyte according to the first embodiment.
  • the positive electrode 201 contains a material capable of absorbing and releasing metal ions (e.g., lithium ions).
  • the material is, for example, the positive electrode active material 204.
  • Examples of the positive electrode active material 204 include a lithium-containing transition metal oxide, a transition metal fluoride, a polyanion, a fluorinated polyanion material, a transition metal sulfide, a transition metal oxyfluoride, a transition metal oxysulfide, or a transition metal oxynitride.
  • Examples of the lithium-containing transition metal oxide include Li(Ni,Co,Mn) O2 , Li(Ni,Co,Al) O2 , or LiCoO2 .
  • (A, B, C) means "at least one selected from the group consisting of A, B, and C.”
  • the shape of the positive electrode active material 204 is not limited to a specific shape.
  • the positive electrode active material 204 may be particles.
  • the positive electrode active material 204 may have a median diameter of 0.1 ⁇ m or more and 100 ⁇ m or less. When the positive electrode active material 204 has a median diameter of 0.1 ⁇ m or more, the positive electrode active material 204 and the solid electrolyte 100 can be well dispersed in the positive electrode 201. This improves the charge and discharge characteristics of the battery 1000. When the positive electrode active material 204 has a median diameter of 100 ⁇ m or less, the lithium diffusion rate in the positive electrode active material 204 improves. This allows the battery 1000 to operate at a high output.
  • the positive electrode active material 204 may have a median diameter larger than that of the solid electrolyte 100. This allows the positive electrode active material 204 and the solid electrolyte 100 to be well dispersed in the positive electrode 201.
  • the ratio of the volume of the positive electrode active material 204 to the sum of the volume of the positive electrode active material 204 and the volume of the solid electrolyte 100 may be 0.30 or more and 0.95 or less.
  • a coating layer may be formed on at least a portion of the surface of the positive electrode active material 204.
  • the coating layer may be formed on the surface of the positive electrode active material 204, for example, before mixing with the conductive assistant and the binder.
  • coating materials included in the coating layer include a sulfide solid electrolyte, an oxide solid electrolyte, or a halide solid electrolyte.
  • the coating material may contain a halide solid electrolyte according to the first embodiment in order to suppress oxidative decomposition of the sulfide solid electrolyte.
  • the coating material may contain an oxide solid electrolyte in order to suppress oxidative decomposition of the solid electrolyte.
  • Lithium niobate which has excellent stability at high potentials, may be used as the oxide solid electrolyte. By suppressing oxidative decomposition, the overvoltage rise of the battery 1000 can be suppressed.
  • the positive electrode material may include the halide solid electrolyte according to the first embodiment as the solid electrolyte 100, or may include it as a coating material that coats the positive electrode active material 204.
  • the positive electrode 201 may have a thickness of 10 ⁇ m or more and 500 ⁇ m or less.
  • the electrolyte layer 202 contains an electrolyte material.
  • the electrolyte material is, for example, a solid electrolyte.
  • the solid electrolyte may include the halide solid electrolyte according to the first embodiment.
  • the electrolyte layer 202 may be a solid electrolyte layer.
  • the electrolyte layer 202 may contain 50% by mass or more of the halide solid electrolyte according to the first embodiment.
  • the electrolyte layer 202 may contain 70% by mass or more of the halide solid electrolyte according to the first embodiment.
  • the electrolyte layer 202 may contain 90% by mass or more of the halide solid electrolyte according to the first embodiment.
  • the electrolyte layer 202 may consist of only the halide solid electrolyte according to the first embodiment.
  • the halide solid electrolyte according to the first embodiment will be referred to as the first solid electrolyte.
  • a solid electrolyte different from the first solid electrolyte will be referred to as the second solid electrolyte.
  • the electrolyte layer 202 may contain not only the first solid electrolyte but also the second solid electrolyte. In the electrolyte layer 202, the first solid electrolyte and the second solid electrolyte may be uniformly dispersed. A layer made of the first solid electrolyte and a layer made of the second solid electrolyte may be stacked along the stacking direction of the battery 1000.
  • the battery according to the second embodiment may include a positive electrode 201, a second electrolyte layer, a first electrolyte layer, and a negative electrode 203 in this order.
  • the solid electrolyte contained in the first electrolyte layer may have a lower reduction potential than the solid electrolyte contained in the second electrolyte layer. This allows the solid electrolyte contained in the second electrolyte layer to be used without being reduced. As a result, the charge/discharge efficiency of the battery 1000 can be improved.
  • the first electrolyte layer may contain a sulfide solid electrolyte in order to suppress the reductive decomposition of the solid electrolyte.
  • the second electrolyte layer may contain the first solid electrolyte. Since the first solid electrolyte has high oxidation resistance, a battery with excellent charge/discharge characteristics can be realized.
  • the electrolyte layer 202 may consist only of the second solid electrolyte.
  • the electrolyte layer 202 may have a thickness of 1 ⁇ m or more and 1000 ⁇ m or less. If the electrolyte layer 202 has a thickness of 1 ⁇ m or more, the positive electrode 201 and the negative electrode 203 are less likely to short-circuit. If the electrolyte layer 202 has a thickness of 1000 ⁇ m or less, the battery 1000 can operate at high power.
  • Examples of the second solid electrolyte are Li2MgX4 , Li2FeX4 , Li(Al,Ga,In) X4 , Li3 (Al,Ga,In) X6 , or LiI, where X is at least one selected from the group consisting of F, Cl, Br, and I.
  • the electrolyte layer 202 may have a thickness of 1 ⁇ m or more and 1000 ⁇ m or less.
  • the negative electrode 203 contains a material capable of absorbing and releasing metal ions (e.g., lithium ions).
  • the material is, for example, the negative electrode active material 205.
  • Examples of the negative electrode active material 205 are metal materials, carbon materials, oxides, nitrides, tin compounds, or silicon compounds.
  • the metal material may be a single metal or an alloy.
  • Examples of the metal material are lithium metal or lithium alloys.
  • Examples of the carbon material are natural graphite, coke, partially graphitized carbon, carbon fiber, spherical carbon, artificial graphite, or amorphous carbon. From the viewpoint of capacity density, suitable examples of the negative electrode active material are silicon (i.e., Si), tin (i.e., Sn), silicon compounds, or tin compounds.
  • the negative electrode active material 205 may be selected in consideration of the reduction resistance of the solid electrolyte contained in the negative electrode 203.
  • the negative electrode active material 205 may be a material capable of absorbing and releasing lithium ions at 0.27 V or more relative to lithium.
  • examples of such negative electrode active materials are titanium oxide, indium metal , or lithium alloy.
  • examples of titanium oxide are Li4Ti5O12 , LiTi2O4 , or TiO2 .
  • the shape of the negative electrode active material 205 is not limited to a specific shape.
  • the negative electrode active material 205 may be particles.
  • the negative electrode active material 205 may have a median diameter of 0.1 ⁇ m or more and 100 ⁇ m or less.
  • the negative electrode active material 205 and the solid electrolyte 100 can be well dispersed in the negative electrode 203. This improves the charge and discharge characteristics of the battery 1000.
  • the negative electrode active material 205 has a median diameter of 100 ⁇ m or less, the lithium diffusion rate in the negative electrode active material 205 improves. This allows the battery 1000 to operate at a high output.
  • the negative electrode active material 205 may have a median diameter larger than that of the solid electrolyte 100. This allows the negative electrode active material 205 and the solid electrolyte 100 to be well dispersed in the negative electrode 203.
  • the ratio of the volume of the negative electrode active material 205 to the sum of the volume of the negative electrode active material 205 and the volume of the solid electrolyte 100 may be 0.30 or more and 0.95 or less.
  • the negative electrode 203 may have a thickness of 10 ⁇ m or more and 500 ⁇ m or less.
  • At least one selected from the group consisting of the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a second solid electrolyte for the purpose of increasing ionic conductivity, chemical stability, and electrochemical stability.
  • the second solid electrolyte may be a sulfide solid electrolyte.
  • Examples of sulfide solid electrolytes are Li2S - P2S5 , Li2S - SiS2 , Li2S - B2S3 , Li2S - GeS2 , Li3.25Ge0.25P0.75S4 , or Li10GeP2S12 .
  • the negative electrode 203 may contain a sulfide solid electrolyte to suppress reductive decomposition of the solid electrolyte.
  • the negative electrode active material By covering the negative electrode active material with an electrochemically stable sulfide solid electrolyte, it is possible to suppress the first solid electrolyte from coming into contact with the negative electrode active material. As a result, the internal resistance of the battery 1000 can be reduced.
  • the second solid electrolyte may be an oxide solid electrolyte.
  • oxide solid electrolytes include: (i) NASICON-type solid electrolytes such as LiTi2 ( PO4 ) 3 or elemental substitutions thereof; (ii) Perovskite-type solid electrolytes such as (LaLi) TiO3 ; (iii ) LISICON-type solid electrolytes such as Li14ZnGe4O16, Li4SiO4 , LiGeO4 or elemental substitutions thereof ; (iv) a garnet-type solid electrolyte such as Li7La3Zr2O12 or its elemental substitutions, or (v) Li3PO4 or its N - substituted derivatives ; It is.
  • the second solid electrolyte may be a halide solid electrolyte.
  • halide solid electrolytes are Li2MgX4 , Li2FeX4 , Li(Al,Ga,In) X4 , Li3 (Al,Ga,In) X6 , or LiI, where X is at least one selected from the group consisting of F, Cl, Br, and I.
  • halide solid electrolyte is a compound represented by Li a Me b Y c Z 6.
  • Me is at least one selected from the group consisting of metal elements other than Li and Y and metalloid elements.
  • Z is at least one selected from the group consisting of F, Cl, Br, and I.
  • m represents the valence of Me.
  • Metalloid elements are B, Si, Ge, As, Sb, and Te.
  • Metal elements are all elements included in Groups 1 to 12 of the periodic table (excluding hydrogen), and all elements included in Groups 13 to 16 of the periodic table (excluding B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se).
  • Me may be at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, and Nb.
  • the halide solid electrolyte may be Li3YCl6 or Li3YBr6 .
  • the second solid electrolyte may be an organic polymer solid electrolyte.
  • organic polymer solid electrolytes examples include polymer compounds and lithium salt compounds.
  • the polymer compound may have an ethylene oxide structure.
  • a polymer compound having an ethylene oxide structure can contain a large amount of lithium salt, and therefore can further increase the ionic conductivity.
  • lithium salt examples include LiPF6 , LiBF4 , LiSbF6, LiAsF6 , LiSO3F3 , LiN ( SO2CF3 ) 2 , LiN (SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), or LiC(SO2CF3)3 .
  • One type of lithium salt selected from these may be used alone. Alternatively, a mixture of two or more types of lithium salts selected from these may be used.
  • At least one selected from the group consisting of the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a nonaqueous electrolyte, a gel electrolyte, or an ionic liquid to facilitate the transfer of lithium ions and improve the output characteristics of the battery.
  • the non-aqueous electrolyte contains a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent.
  • non-aqueous solvents examples include cyclic carbonate solvents, chain carbonate solvents, cyclic ether solvents, chain ether solvents, cyclic ester solvents, chain ester solvents, or fluorine solvents.
  • cyclic carbonate solvents are ethylene carbonate, propylene carbonate, or butylene carbonate.
  • chain carbonate solvents are dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate.
  • Examples of cyclic ether solvents are tetrahydrofuran, 1,4-dioxane, or 1,3-dioxolane.
  • chain ether solvents are 1,2-dimethoxyethane or 1,2-diethoxyethane.
  • An example of a cyclic ester solvent is ⁇ -butyrolactone.
  • An example of a chain ester solvent is methyl acetate.
  • fluorine solvents are fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoroethyl methyl carbonate, or fluorodimethylene carbonate.
  • One type of non-aqueous solvent selected from these may be used alone. Alternatively, a combination of two or more types of non-aqueous solvents selected from these may be used.
  • lithium salt examples include LiPF6 , LiBF4 , LiSbF6, LiAsF6 , LiSO3CF3 , LiN ( SO2CF3 ) 2 , LiN ( SO2C2F5 ) 2 , LiN( SO2CF3 )(SO2C4F9), or LiC( SO2CF3 ) 3 .
  • One type of lithium salt selected from these may be used alone. Alternatively, a mixture of two or more types of lithium salts selected from these may be used.
  • the concentration of the lithium salt is, for example , in the range of 0.5 mol/L or more and 2 mol/L or less.
  • a polymer material impregnated with a non-aqueous electrolyte may be used.
  • polymer materials are polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, or a polymer having an ethylene oxide bond.
  • cations contained in ionic liquids are: (i) Aliphatic chain quaternary salts such as tetraalkylammonium or tetraalkylphosphonium; (ii) aliphatic cyclic ammoniums such as pyrrolidiniums, morpholiniums, imidazoliniums, tetrahydropyrimidiniums, piperaziniums, or piperidiniums, or (iii) nitrogen-containing heterocyclic aromatic cations such as pyridiniums or imidazoliums.
  • Aliphatic chain quaternary salts such as tetraalkylammonium or tetraalkylphosphonium
  • aliphatic cyclic ammoniums such as pyrrolidiniums, morpholiniums, imidazoliniums, tetrahydropyrimidiniums, piperaziniums, or piperidiniums
  • nitrogen-containing heterocyclic aromatic cations such as
  • Examples of anions contained in the ionic liquid are PF6- , BF4- , SbF6- , AsF6- , SO3CF3- , N ( SO2CF3 ) 2- , N ( SO2C2F5 ) 2- , N( SO2CF3 ) ( SO2C4F9 ) - , or C ( SO2CF3 ) 3- .
  • the ionic liquid may contain a lithium salt.
  • At least one selected from the group consisting of the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a binder to improve adhesion between particles.
  • binders are polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, polyacrylic acid methyl ester, polyacrylic acid ethyl ester, polyacrylic acid hexyl ester, polymethacrylic acid, polymethacrylic acid methyl ester, polymethacrylic acid ethyl ester, polymethacrylic acid hexyl ester, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, hexafluoropolypropylene, styrene butadiene rubber, or carboxymethylcellulose.
  • Copolymers may also be used as binders.
  • binders are copolymers of two or more materials selected from the group consisting of tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene.
  • a mixture of two or more of these materials may be used as a binder.
  • At least one selected from the positive electrode 201 and the negative electrode 203 may contain a conductive additive to improve electronic conductivity.
  • Examples of the conductive additive include: (i) graphites, such as natural or synthetic graphite; (ii) Carbon blacks such as acetylene black or ketjen black; (iii) conductive fibers, such as carbon or metal fibers; (iv) fluorocarbons, (v) metal powders such as aluminum; (vi) conductive whiskers such as zinc oxide or potassium titanate; (vii) a conductive metal oxide such as titanium oxide, or (viii) a conductive polymer compound such as polyaniline, polypyrrole, or polythiophene.
  • the conductive assistant of (i) or (ii) above may be used.
  • a separator impregnated with an electrolyte solution may be used instead of the electrolyte layer, and the inside of the exterior housing the positive electrode, the separator portion, and the negative electrode may be filled with the electrolyte solution.
  • the electrolyte solution may be, for example, the nonaqueous electrolyte solution described above.
  • shapes of the battery according to the second embodiment include a coin type, a cylindrical type, a square type, a sheet type, a button type, a flat type, or a laminated type.
  • the battery according to the second embodiment may be manufactured, for example, by preparing a material for forming a positive electrode, a material for forming an electrolyte layer, and a material for forming a negative electrode, and producing a laminate in which the positive electrode, electrolyte layer, and negative electrode are arranged in this order using a known method.
  • a halide solid electrolyte comprising Li, Al, M, and X
  • the M is at least one element selected from the group consisting of metal elements (excluding Li and Al) and metalloid elements
  • X is at least one selected from the group consisting of F, Cl, Br, and I
  • the halide solid electrolyte is a first particle group consisting of first particles constituted by a compound A containing Al and the X; a second particle group consisting of second particles constituted of a compound B that does not contain Al and contains the M and the X; Including, In the first particle group, a coefficient of variation CV Al calculated by the following formula (A) using a standard deviation ⁇ Al of the ratio Al/X of the mass of Al to the mass of X and an average value A Al of the ratio Al /X is 10% or less, In the second particle group, a coefficient of variation CV M calculated by the following formula (B) using a standard deviation ⁇ M of the ratio M/X of the mass of M to the mass of X and an
  • the above configuration makes it possible to obtain a halide solid electrolyte with excellent ionic conductivity. Furthermore, the above configuration makes it possible to obtain a highly reliable halide solid electrolyte with excellent stability (e.g., heat resistance and resistance to atmospheric environments). Therefore, the above configuration makes it possible to obtain a halide solid electrolyte with excellent ionic conductivity and reliability.
  • composition formula (1) Li 3 (Al 1-y1 M y1 )X 6
  • composition formula (2) Li 2 MX 6 In the composition formula (1), y1 satisfies 0 ⁇ y1 ⁇ 1.
  • a halide solid electrolyte with improved reliability can be obtained by using a mixed structure of compound A and compound B, which have a high Li ion content and high ionic conductivity.
  • composition formula (3) Li 3 AlX 6
  • a halide solid electrolyte with improved reliability can be obtained by using a mixed structure of compound A and compound B, which have a high Li ion content and high ionic conductivity.
  • the first particle group includes particles including a first crystal phase represented by the following composition formula (4) and a second crystal phase represented by the following composition formula (5):
  • the first crystal phase and the second crystal phase are contained in one particle.
  • a halide solid electrolyte with improved reliability can be obtained.
  • a molar ratio of the first crystal phase to a total of the first crystal phase and the second crystal phase is 0.05 or more and 0.95 or less. 5.
  • halide solid electrolyte with higher ionic conductivity (e.g., 1.0 ⁇ S/cm or higher).
  • the X includes F.
  • halide solid electrolyte with excellent stability e.g., electrochemical stability and heat resistance
  • excellent stability e.g., electrochemical stability and heat resistance
  • the M includes Ti.
  • the above configuration makes it possible to obtain a halide solid electrolyte with higher ionic conductivity. Furthermore, by including Ti, the solid-phase reaction temperature can be lowered (for example, to 750°C or less), which means that the reaction can be accelerated. As a result, a homogeneous halide solid electrolyte with excellent ionic conductivity can be obtained.
  • the M includes Ti, The y1 satisfies 0 ⁇ y1 ⁇ 0.3, The halide solid electrolyte according to claim 2 or 3.
  • the M includes Ti, The y2 satisfies 0 ⁇ y2 ⁇ 0.3, 6.
  • halide solid electrolyte with higher ionic conductivity (e.g., 1.0 ⁇ S/cm or higher).
  • the first crystal phase has an orthorhombic crystal structure. 5.
  • the above configuration makes it possible to obtain a halide solid electrolyte with higher ionic conductivity (e.g., 3.0 ⁇ S/cm or higher).
  • the M includes Ti. 12.
  • the above configuration makes it possible to obtain a halide solid electrolyte with even higher ionic conductivity (e.g., 6.0 ⁇ S/cm or higher).
  • the ratio Al/X is equal to or greater than (the average value A Al - 3 ⁇ the standard deviation ⁇ Al ) and equal to or less than (the average value A Al + 3 ⁇ the standard deviation ⁇ Al ); 13.
  • the halide solid electrolyte according to any one of claims 1 to 12.
  • the above configuration reduces particles with a composition that has low ionic conductivity, making it possible to obtain a halide solid electrolyte with higher ionic conductivity (e.g., 1.0 ⁇ S/cm or more, or 3.0 ⁇ S/cm or more).
  • the ratio M/X is equal to or greater than (the average value A M - 3 ⁇ the standard deviation ⁇ M ) and equal to or less than (the average value A M + 3 ⁇ the standard deviation ⁇ M ); 14.
  • the halide solid electrolyte according to any one of claims 1 to 13.
  • the above configuration reduces particles with a composition that has low ionic conductivity, making it possible to obtain a halide solid electrolyte with higher ionic conductivity (e.g., 1.0 ⁇ S/cm or more, or 3.0 ⁇ S/cm or more).
  • the ratio Al/X is equal to or greater than (the average value A Al - 3 x the standard deviation ⁇ Al ) and equal to or less than (the average value A Al + 3 x the standard deviation ⁇ Al ), and the ratio M/X is equal to or greater than (the average value A M - 3 x the standard deviation ⁇ M ) and equal to or less than (the average value A M + 3 x the standard deviation ⁇ M ).
  • the halide solid electrolyte according to any one of claims 1 to 14.
  • the above configuration reduces particles with a composition that has low ionic conductivity, making it possible to obtain a halide solid electrolyte with higher ionic conductivity (e.g., 1.0 ⁇ S/cm or more, or 3.0 ⁇ S/cm or more).
  • halide solid electrolyte that has both high ionic conductivity (e.g., 1.0 ⁇ S/cm or more) and low electronic conductivity (e.g., 0.01 ⁇ S/cm or less).
  • high ionic conductivity e.g., 1.0 ⁇ S/cm or more
  • low electronic conductivity e.g. 0.01 ⁇ S/cm or less.
  • the amorphous phase is soft and easily deformed. Therefore, when the halide solid electrolyte of Technology 16 is compressed into a powder body, an interface where the particles are in close contact with each other is easily formed, making it easy to increase the density and make it thin, and it is also expected to have improved ionic conductivity.
  • the halide solid electrolyte of Technology 16 is used in, for example, the solid electrolyte layer of a battery, it is possible to realize a thin solid electrolyte layer, and it can be suitably used as a coating layer for active material particles.
  • the volume of the amorphous phase contained in the second particle is larger than the volume of the amorphous phase contained in the first particle. 17.
  • the above configuration can further improve ionic conductivity and reliability.
  • the above configuration makes the halide solid electrolyte softer and easier to deform, improving the adhesion between particles and reducing voids between particles. Therefore, the halide solid electrolyte according to Technology 17 can be densified when pressed into a powder. This allows, for example, when used in a solid electrolyte layer of a battery, to densify the solid electrolyte layer, and can be suitably used as a coating layer for active material particles.
  • the amorphous phase contained in the first particle has a higher ionic conductivity than the amorphous phase contained in the second particle; 18.
  • the softer second particles can bond between the first particles, which have a higher ionic conductivity, so high ionic conductivity can be obtained.
  • the amorphous phase has lower electronic conductivity than the portions of the first particle and the second particle other than the amorphous phase; 19.
  • the halide solid electrolyte according to any one of claims 16 to 18.
  • the amorphous phase has lower electronic conductivity (e.g., 0.01 ⁇ S/cm or less) than the portion other than the amorphous phase, resulting in a halide solid electrolyte with superior ionic conductivity.
  • the above configuration makes it possible to realize a solid electrolyte layer for a battery or a coating layer for active material particles that has excellent ionic conductivity and reliability.
  • the halide solid electrolyte contains at least one selected from the group consisting of Nb and Ga. 21.
  • the above configuration accelerates the synthesis reaction from the starting material to a halide solid electrolyte, making it possible to efficiently obtain a halide solid electrolyte with excellent ionic conductivity and reliability.
  • the positive electrode material developed by Technology 22 makes it possible to realize high-performance batteries with excellent charge/discharge characteristics.
  • This configuration makes it possible to provide a battery with excellent charging and discharging characteristics.
  • This configuration makes it possible to provide a high-performance battery with excellent charge and discharge characteristics.
  • Example 1 5 is a flow diagram of a method for producing a halide solid electrolyte of Example 1.
  • a halide solid electrolyte was synthesized in which the compound A constituting the first particle was represented by the composition formula Li3 ( Al0.85Ti0.15 ) F6 , and the compound B constituting the second particle was represented by the composition formula Li2TiX6 . That is, in Example 1, M was Ti.
  • first particles composed of compound A and second particles composed of compound B were produced, respectively.
  • first particles first, five particles A1, A2, A3, A4, and A5 having an average composition Li 3 (Al 0.85 Ti 0.15 )F 6 which is the composition of the target compound A and slightly different from each other in Al content were preliminarily synthesized.
  • the starting materials were mixed so as to have a composition in which Al was reduced by 2% from the composition of the target compound A , Li3 ( Al0.85Ti0.15 ) F6 , i.e., the mixing ratio of the starting materials was such that the amount of Al was reduced by 2 % in molar ratio compared to the amount of Al charged when Li3(Al0.85Ti0.15) F6 was the target.
  • the starting materials were mixed so as to have a composition in which Al was reduced by 1% from the composition of the target compound A , Li3 ( Al0.85Ti0.15 ) F6 , i.e., the mixing ratio of the starting materials was such that the amount of Al was reduced by 1 % in molar ratio compared to the amount of Al charged when Li3(Al0.85Ti0.15) F6 was the target.
  • batch A3 the starting materials were mixed in a ratio that resulted in the composition of the desired compound A, Li3 ( Al0.85Ti0.15 ) F6 . That is, in batch A3, the change in Al from the composition of the desired compound A, Li3 ( Al0.85Ti0.15 ) F6 , was 0%.
  • the starting materials were mixed so as to have a composition in which Al was +1% compared to the composition of the target compound A , Li3 ( Al0.85Ti0.15 ) F6 , i.e., the mixing ratio of the starting materials was such that the amount of Al was increased by 1% in molar ratio compared to the amount of Al charged when Li3 (Al0.85Ti0.15 ) F6 was the target.
  • the starting materials were mixed so as to have a composition in which Al was +2% compared to the composition of the target compound A , Li3 ( Al0.85Ti0.15 ) F6 , i.e., the mixing ratio of the starting materials was such that the amount of Al was increased by 2% in molar ratio compared to the amount of Al charged when Li3 (Al0.85Ti0.15 ) F6 was the target.
  • the starting materials were mixed so as to have a composition in which Ti was -3% of the composition Li 2 TiX 6 of the target compound B, that is, the mixing ratio of the starting materials was such that Ti was reduced by 3% in molar ratio from the amount of Ti charged in the case where Li 2 TiX 6 was the target.
  • the starting materials were mixed so that the composition of the target compound B, Li 2 TiX 6, would have a Ti content of -1%, i.e., the mixing ratio of the starting materials would be 1% Ti less in molar ratio than the amount of Ti charged when Li 2 TiX 6 was the target.
  • batch B3 the starting materials were mixed in a ratio that resulted in the composition of the target compound B, Li 2 TiX 6. That is, in batch B3, the change in Ti from the composition of the target compound B, Li 2 TiX 6, was 0%.
  • the starting materials were mixed so that the composition of the target compound B, Li 2 TiX 6, would have a Ti content of +1%, i.e., the mixing ratio of the starting materials was such that the amount of Ti was increased by 1% in molar ratio compared to the amount of Ti charged when Li 2 TiX 6 was the target.
  • batch B5 the starting materials were mixed so that the composition of the target compound B, Li 2 TiX 6, would have a Ti content of +3%, i.e., the mixing ratio of the starting materials was such that the amount of Ti was increased by 3% in molar ratio compared to the amount of Ti charged when Li 2 TiX 6 was the target.
  • the first particles and the second particles were placed in a 600 mL ball mill having a zirconia inner wall together with a zirconia ball having a diameter of 5 mm, and dry mixed for 20 hours, and the mixed powder was collected as the halide solid electrolyte of Example 1.
  • This dry ball mill treatment including the mechanochemical treatment also caused amorphization to proceed simultaneously with the synthesis of the halide solid electrolyte. That is, the obtained halide solid electrolyte of Example 1 contained an amorphous phase.
  • the ionic conductivity was calculated from the area, thickness, and impedance characteristics at room temperature of a compact sample obtained by putting a halide solid electrolyte powder into a mold having a diameter of 10 mm and applying a pressure of about 3 t/cm using a uniaxial hydraulic press. The impedance measurement was performed at room temperature while applying pressure. The impedance measurement was performed at a measurement frequency of 10 Hz to 10 MHz, a measurement voltage of 1 Vrms, and no DC bias. The deviation in the electrical length of the cable and the measuring jig was offset and evaluated.
  • the ionic conductivity of the halide solid electrolyte of Example 1 was 7.1 ⁇ S/cm, and the ionic conductivity of the halide solid electrolyte of Comparative Example 1 was 0.93 ⁇ S/cm.
  • the electronic conductivity was calculated from the DC voltage and current characteristics.
  • the electronic conductivity of the halide solid electrolyte of Example 1 was ⁇ 0.01 ⁇ S/cm.
  • the electronic conductivity of the halide solid electrolyte of Comparative Example 1 was 0.017 ⁇ S/cm.
  • a compact sample of a halide solid electrolyte was prepared in the same manner as the compact sample prepared in the measurement of ionic conductivity.
  • a cross-section of the compact sample was formed using a cross-section polisher (CP).
  • An elemental analysis point analysis was performed on a plurality of arbitrary spots on the cross-section with a spot diameter (diameter) of 1 ⁇ m using EPMA.
  • the spots identified as the first particles and the spots identified as the second particles were divided by the elemental analysis using EPMA, and 20 spots were arbitrarily selected from each of the spots identified as the first particles and the spots identified as the second particles.
  • the standard deviation ⁇ Al and the average value A Al of the ratio Al/X were obtained to calculate the coefficient of variation CV Al .
  • the standard deviation ⁇ M and the average value A M of the ratio M/X were obtained to calculate the coefficient of variation CV M.
  • the standard deviation ⁇ Al was 0.01013, the average value A Al was 0.1512, and the coefficient of variation CV Al was 6.7%, while the standard deviation ⁇ M was 0.01683, the average value A M was 0.1503, and the coefficient of variation CV M was 11.2%.
  • the standard deviation ⁇ Al was 0.02084, the average value A Al was 0.1408, and the coefficient of variation CV Al was 14.8%, while the standard deviation ⁇ M was 0.03711, the average value A M was 0.139, and the coefficient of variation CV M was 26.7%.
  • the halide solid electrolyte of Example 1 in which the coefficient of variation CV Al was 10% or less and the coefficient of variation CV M was 20% or less, had a higher ionic conductivity than the halide solid electrolyte of Comparative Example 1, in which the coefficient of variation CV Al exceeded 10% and the coefficient of variation CV M exceeded 20%.
  • the halide solid electrolyte according to the present disclosure can be used, for example, as a solid electrolyte for secondary batteries such as all-solid-state batteries used in various electronic devices or automobiles.

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US20190067694A1 (en) * 2016-04-29 2019-02-28 Iucf-Hyu (Industry-University Cooperation Foundation Hanyang University) Cathode active material, method for manufacturing same, and lithium secondary battery comprising same
WO2022239352A2 (ja) * 2021-05-10 2022-11-17 パナソニックＩｐマネジメント株式会社 固体電解質、固体電解質の製造方法、および電池

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US20190067694A1 (en) * 2016-04-29 2019-02-28 Iucf-Hyu (Industry-University Cooperation Foundation Hanyang University) Cathode active material, method for manufacturing same, and lithium secondary battery comprising same
WO2022239352A2 (ja) * 2021-05-10 2022-11-17 パナソニックＩｐマネジメント株式会社 固体電解質、固体電解質の製造方法、および電池

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