A sulfide solid electrolyte and a full solid lithium battery

Abstract

This application relates to the field of electrochemical technology, and provides a sulfide solid electrolyte and an all-solid-state lithium battery. The chemical formula of the sulfide solid electrolyte is Li. 7+x‑y P 1‑x M x S 6‑2x‑y O 2x X y M is at least one of the variable-valence rare earth elements Ce, Eu, Pr, and Sm, and X is at least one of the halogens, with 0.002 ≤ x ≤ 0.3 and 0.5 ≤ y ≤ 1.4. The molar ratio of M to O is 1:2. The cell parameters of the sulfide solid electrolyte satisfy a = b = c = 9.85~10 Å, and the ionic conductivity of the sulfide solid electrolyte is > 8 mS / cm. Through the above settings, the sulfide solid electrolyte of this application exhibits good structural stability and oxidation-reduction resistance, as well as good air stability and ionic conductivity, thereby achieving a longer cycle life and stronger voltage withstand performance in all-solid-state lithium batteries.

Description

Technical Field

[0001] This application relates to the field of electrochemical technology, and in particular to a sulfide solid electrolyte and an all-solid-state lithium battery. Background Technology

[0002] Sulfide solid electrolytes are considered one of the core materials for next-generation all-solid-state lithium batteries due to their excellent ionic conductivity and flexible mechanical properties. However, sulfide solid electrolytes often exhibit structural instability and high interfacial reactivity during battery charge-discharge cycles. Especially when used in conjunction with high-voltage cathode materials and lithium metal, they are prone to electrolyte oxidation or reduction decomposition, migration of active sulfur elements, or framework structural collapse, ultimately leading to battery capacity decay and shortened lifespan. These problems are mainly attributed to [PS4] in sulfide solid electrolytes. 3- The tetrahedral unit cell lacks chemical stability under high electrochemical stress conditions, and phosphorus (P) in its framework... 5+ ) and sulfur (S) 2- The coordination environment formed by sulfide solid electrolytes is easily degraded by external disturbances. Current stabilization strategies mostly focus on interfacial coatings or lithium site substitution, failing to fundamentally improve the framework stability at the electrolyte bulk structure level. Furthermore, sulfide solid electrolytes decompose readily in air, generating harmful gases such as hydrogen sulfide upon contact with moisture or oxygen, accompanied by structural damage and a significant decrease in electrochemical performance. This air stability deficiency severely limits the reliability of sulfide solid electrolytes in industrial production, storage, transportation, and practical applications.

[0003] Therefore, it is urgent to develop novel doping design methods to enhance the structural stability and oxidation-reduction resistance of sulfide solid electrolytes from within the crystal framework, while also improving the air stability of sulfide solid electrolytes, in order to achieve longer cycle life and stronger voltage resistance of all-solid-state lithium batteries. Summary of the Invention

[0004] The purpose of this application is to provide a sulfide solid electrolyte and an all-solid-state lithium battery to enhance the structural stability and oxidation-reduction resistance of the sulfide solid electrolyte, while improving its air stability and ionic conductivity, thereby achieving a longer cycle life and stronger voltage withstand performance in the all-solid-state lithium battery. The specific technical solution is as follows:

[0005] The first aspect of this application provides a sulfide solid electrolyte with the chemical formula Li. 7+x-y P 1-x M x S 6-2x- y O 2x X yM is at least one of the variable-valence rare earth elements Ce, Eu, Pr and Sm, X is at least one of the halogens, 0.002≤x≤0.3, 0.5≤y≤1.4, and the molar ratio of M to O is 1:2; the cell parameters of the sulfide solid electrolyte satisfy: a=b=c=9.85~10Å, and the ionic conductivity of the sulfide solid electrolyte is >8mS / cm.

[0006] In one embodiment of this application, 0.02≤x≤0.1, 1.25≤y≤1.4.

[0007] In one embodiment of this application, X is at least one of Cl, Br, and I.

[0008] In one embodiment of this application, the chemical formula of the sulfide solid electrolyte is Li. 7+x-y P 1- x M x S 6-2x-y O 2x X' 0.7y X'' 0.3y X' or X'' is independently Cl, Br or I, and X' is different from X''.

[0009] In one embodiment of this application, the chemical formula of the sulfide solid electrolyte is Li. 7+x-y P 1- x M x S 6-2x-y O 2x Cl 0.7y Br 0.3y .

[0010] In one embodiment of this application, the sulfide solid electrolyte is Li 5.77 P 0.98 Ce 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 Li 5.8 P 0.95 Ce 0.05 S 4.65 O 0.1 Cl 0.875 Br 0.375 Li 5.85 P 0.9 Ce 0.1 S 4.55 O 0.2 Cl 0.875 Br 0.375 Li 5.6 5P0.95 Ce 0.05 S 4.5 O 0.1 Cl 0.98 Br 0.42 Li 5.77 P 0.98 Eu 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 Li 5.77 P 0.98 Pr 0.02 S 4.7 1O 0.04 Cl 0.875 Br 0.375 Li 5.77 P 0.98 Sm 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 .

[0011] In one embodiment of this application, the particle size of the sulfide solid electrolyte satisfies: 0.5µm < D50 < 4µm, 7µm < D90 < 10µm.

[0012] The second aspect of this application provides an all-solid-state lithium battery, which includes a positive electrode, a negative electrode, and a sulfide solid electrolyte as described in the first aspect of this application.

[0013] The beneficial effects of this application are:

[0014] This application provides a sulfide solid electrolyte and an all-solid-state lithium battery. The sulfide solid electrolyte has the chemical formula Li. 7+x-y P 1-x M x S 6-2x-y O 2x X yM is at least one of the variable-valence rare earth elements Ce, Eu, Pr, and Sm, and X is at least one of the halogens. The valences are 0.002 ≤ x ≤ 0.3 and 0.5 ≤ y ≤ 1.4. The molar ratio of M to O is 1:2. The cell parameters of the sulfide solid electrolyte satisfy a = b = c = 9.85~10 Å, and the ionic conductivity of the sulfide solid electrolyte is > 8 mS / cm. In this application, the sulfide solid electrolyte is doped with the variable-valence rare earth element M at the P-site and O at the S-site of the silver-germanium sulfide LPSC solid electrolyte. The values ​​of x and y are controlled within the range of this application, and the molar ratio of M to O is controlled to 1:2. The cell parameters of the sulfide solid electrolyte are controlled to satisfy a = b = c = 9.85~10 Å, which enhances the structural stability and oxidation-reduction resistance of the sulfide solid electrolyte, while also improving its air stability and ionic conductivity, thereby achieving a longer cycle life and stronger voltage withstand performance in all-solid-state lithium batteries.

[0015] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these accompanying drawings.

[0017] Figure 1 The sulfide solid electrolyte (Li) prepared in Example 1 5.8 P 0.95 Ce 0.05 S 4.65 O 0.1 Cl 0.875 Br 0.3 75 X-ray diffraction pattern of )

[0018] Figure 2 The sulfide solid electrolyte (Li) prepared in Example 8 5.77 P 0.98 Eu 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 X-ray diffraction pattern of )

[0019] Figure 3 The sulfide solid electrolyte (Li) prepared in Example 9 5.77 P 0.98 Pr 0.02 S4.71 O 0.04 Cl 0.875 Br 0.375 X-ray diffraction pattern of )

[0020] Figure 4 The sulfide solid electrolyte (Li) prepared in Example 10 5.77 P 0.98 Sm 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 X-ray diffraction pattern of )

[0021] Figure 5 The sulfide solid electrolyte (Li) prepared in Comparative Example 6 5.75 PS 4.75 Cl 0.875 Br 0.375 X-ray diffraction pattern of ). Detailed Implementation

[0022] The technical solutions of this application will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0023] The first aspect of this application provides a sulfide solid electrolyte with the chemical formula Li. 7+x-y P 1-x M x S 6-2x- y O 2x X yM is at least one of the variable-valence rare earth elements Ce, Eu, Pr, and Sm, and X is at least one of the halogens. The molar ratio of M to O is 1:2. The unit cell parameters of the sulfide solid electrolyte satisfy a=b=c=9.85~10Å, and the ionic conductivity of the sulfide solid electrolyte is >8 mS / cm. Specifically, "the ionic conductivity of the sulfide solid electrolyte >8 mS / cm" means that after the sulfide solid electrolyte powder is pressurized to 300 MPa, an AC impedance spectroscopy test is performed, and the ionic conductivity of the sulfide solid electrolyte is >8 mS / cm. Preferably, 0.02≤x≤0.1 and 1.25≤y≤1.4. For example, x can be 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3 or a range of any two of these values, and y can be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.25, 1.3, 1.4 or a range of any two of these values.

[0024] In this application, rare earth element M partially replaces P. 5+ Sites, constructing new [MO] x S 4-x Polyhedral structures. These structures possess stronger metal-ligand bond energies and electronic polarization capabilities, significantly enhancing framework rigidity and improving the material's resistance to oxidation stress and electric field disturbances, preventing the original [PS4] 3- The unit cell disintegrates under high voltage. Meanwhile, oxygen anions replace sulfur in the crystal lattice. 2- Subsequently, some P–O or M–O bonds are formed, enhancing the ligand field strength in the crystal lattice and reducing the tendency of sulfur to volatilize, migrate, or be reduced. This doping mechanism can effectively reduce sulfur emissions during battery cycling. 2- Transform into S n Or PS x Side reactions are reduced, improving overall chemical stability. Furthermore, the variable-valence rare earth elements in this application possess unique reversible redox properties (such as Ce). 4+ / Ce 3+ During battery cycling, these phosphorus / sulfur sites can absorb or release electrons, thus forming an intrinsic charge buffer within the framework unit. This dynamically regulates the local electrochemical potential and inhibits framework degradation. This electronic self-regulation mechanism differs from simple interface buffering and is more deeply integrated into the material structure itself. The synergistic effect of phosphorus / sulfur doping and rare earth valence states enables the framework structure to adaptively regulate electrochemical stress, mitigating the risk of material damage caused by structural distortion, electron density fluctuations, and local valence state changes. This enhances the structural stability and oxidation-reduction resistance of the sulfide solid electrolyte, significantly extending the lifespan of all-solid-state lithium batteries and improving their high-voltage performance.

[0025] To further ensure the controllability and functionality of the doping effect, this application limits the molar ratio of rare earth element M to oxygen element O to 1:2, that is, each rare earth metal ion corresponds to two oxygen ions, thereby forming a stable doping effect in the material. or Type-dependent coordination structural unit. This proportional limitation effectively avoids [the following issues]. Excessive introduction of rare earth elements can lead to lattice expansion, formation of crystalline impurities, or disorder of anion sites. It also prevents the isolated existence of rare earth ions without stable coordination, which could induce a decrease in conductivity or accumulation of structural defects. Under this molar ratio, the formed rare earth-oxygen structure is not only stably embedded in the electrolyte lattice but also possesses a highly ordered local structure. This helps improve lattice rigidity and bonding energy, enhancing the resistance of sulfide solid electrolyte materials to external thermal disturbances and electrochemical stresses, thereby strengthening their structural stability. Furthermore, limiting the molar ratio of M to O to 1:2 ensures that rare earth element M forms a complete electron buffer structure in the lattice. During charging and discharging, it can absorb excess electrons through its reversible redox behavior, suppressing charge accumulation caused by interfacial side reactions, thus delaying interfacial aging and maintaining interfacial electrochemical stability. In contrast, if the molar ratio of M to O is unbalanced, it may cause rare earth enrichment, interfering with the lattice structure, or lead to instability of the buffer structure due to insufficient oxygen content, thereby weakening the overall performance of the material.

[0026] Furthermore, rare earth element doping at P sites optimizes the migration pathway of lithium ions by altering the stoichiometric balance of the crystal and inducing global lattice defects. Specifically, rare earth ions (e.g., Ce) 4+ ) Replace P 5+ At this stage, due to the lower oxidation state of rare earth ions, sulfur vacancies or other anionic defects need to be introduced to maintain the electroneutrality of the crystal. These sulfur vacancies disrupt the symmetry of the original sulfide framework structure, thereby enhancing the channel connectivity and migration ability of lithium ions. Furthermore, p-site doping of rare earth ions affects the overall bonding strength of the crystal, for example, weakening some Li-S bonds and altering the local environment of surrounding lithium ions, further reducing the migration barrier of lithium ions. P-site doping of rare earth ions has a significant effect on improving air stability due to the variable valence characteristics of rare earth ions (e.g., Ce). 3+ and Ce 4+Rare earth elements possess excellent redox buffering capabilities, capable of capturing oxidizing or reducing intermediates produced by sulfide decomposition, thereby weakening the decomposition reaction, reducing the generation of hydrogen sulfide decomposition products, and slowing down the degradation rate of materials in humid or oxidizing environments. Simultaneously, the variable valence properties of rare earth elements allow them to form a stable passivation layer in the interfacial region, reducing the sensitivity of sulfides to oxygen and water in the air, further reducing side reactions with air or electrode materials, thus slowing down oxidative degradation and improving the stability of the material. Furthermore, the variable oxidation state of rare earth ions can reduce the material's moisture adsorption and reactivity through the introduction of oxygen vacancies, further enhancing its stability in humid environments.

[0027] Furthermore, by controlling the value of x to be 0.002 ≤ x ≤ 0.3, within the aforementioned range, the variable-valence rare-earth doping can introduce oxygen coordination centers, forming a stable MO bond structure. This helps regulate the electronic state distribution in the crystal and enhances the stabilizing effect on the sulfide framework structure. Simultaneously, this doping level does not cause severe lattice distortion or second-phase precipitation. It allows the cell parameters of the material to be maintained within the range of a = b = c = 9.85~10 Å while effectively introducing lithium vacancies and defects, thus optimizing the crystal structure. Migration channels enhance ionic conductivity. If x < 0.002, the rare earth element doping is too low, and the cell parameter of the material is less than 9.85 Å. At this point, sufficient MO stable structure cannot be formed, and the electron buffering and structural strengthening effects are significantly weakened, resulting in limited improvement in battery performance. If x > 0.3, excessive rare earth doping will cause lattice distortion, impurity phase formation, and M element cluster precipitation, destroying the overall crystal homogeneity and causing the cell parameter of the material to exceed 10 Å. This, in turn, will block ion migration channels and reduce material performance. Meanwhile, controlling 0.5 ≤ y ≤ 1.4, with y within the above range, allows for appropriate halogen doping to replace part of the sulfur element, which helps improve framework rigidity and control cell size, enhancing... The halogen doping concentration improves the connectivity of the migration network and enhances resistance to atmospheric water and oxygen, while maintaining the overall stability of the original sulfide framework and preventing excessive halogen introduction that could lead to crystal brittleness or phase separation. If y < 0.5, the halogen doping ratio is too low, insufficient to effectively improve the material's ionic conductivity and air stability, and unable to provide adequate synergistic regulation at the structural level, easily leading to performance degradation. If y > 1.4, excessive halogen doping can cause severe lattice distortion and the formation of heterogeneous phases, resulting in a rapid decline in ionic conductivity, increased material brittleness, and the induction of side reactions at the electrolyte / electrode interface, reducing its cycling stability.

[0028] Therefore, this application dops the P-site of the sulfide solid electrolyte with variable-valence rare earth element M and the S-site with element O, controls the numerical range of x and y within the range of this application, and controls the molar ratio of element M to element O to be 1:2, controlling the cell parameters of the sulfide solid electrolyte to satisfy: a=b=c=9.85~10Å, which enhances the structural stability and oxidation-reduction resistance of the sulfide solid electrolyte, while improving the air stability and ionic conductivity of the sulfide solid electrolyte, thereby achieving a longer cycle life and stronger voltage resistance of the all-solid-state lithium battery.

[0029] In one embodiment of this application, X is at least one of Cl, Br, and I.

[0030] In one embodiment of this application, the chemical formula of the sulfide solid electrolyte is Li. 7+x-y P 1- x M x S 6-2x-y O 2x X' 0.7y X'' 0.3y X' or X'' is independently Cl, Br, or I, and X' is different from X''. By introducing two halogens into the sulfide solid electrolyte and controlling the molar ratio of the two halogens to 7:3, the coexistence of the two halogens can optimize the bonding state between grains during sintering, reduce stress concentration and defect formation at grain boundaries, and thus reduce grain boundary impedance. The synergistic effect of the two halogens can form a denser and more uniform grain interface, which helps to suppress interfacial reactions and improve the continuity of the overall ion conduction path.

[0031] In one embodiment of this application, the sulfide solid electrolyte has the chemical formula Li. 7+x-y P 1-x M x S 6-2x- y O 2x Cl 0.7y Br 0.3y The sulfide solid electrolyte of this application includes Cl and Br elements, and the molar ratio of Cl to Br elements is controlled at 7:3. and The ionic radii differ ( The ionic radius is approximately 1.81 Å. The ionic radius is approximately 1.96 Å. At a 7:3 ratio, a larger radius can be appropriately introduced while ensuring that the crystal structure is not distorted. This helps alleviate internal stress in the crystal and maintain the stability of the face-centered cubic structure. However, if the Br content is too high, excessive lattice expansion will disrupt the crystal structure. Migration pathways; if the Br ratio is too low, the improvement in electrochemical performance is not significant. Studies have found that 7:3 is a balance point that takes into account both structural stability and functional optimization. Choosing the above sulfide solid electrolytes can further enhance the structural stability and antioxidant capacity of sulfide solid electrolytes, while also further improving the air stability and ionic conductivity of sulfide solid electrolytes, thereby further improving the cycle life and voltage withstand performance of all-solid-state lithium batteries.

[0032] In one embodiment of this application, the chemical formula of the sulfide solid electrolyte is Li. 7+x-y P 1- x Ce x S 6-2x-y O 2x Cl 0.7y Br 0.3y 0.02≤x≤0.1, 1.25≤y≤1.4. Doping Ce at the P-sites and oxygen at the S-sites in the sulfide-germanium LPSC solid electrolyte, with x and y values ​​falling within the aforementioned ranges, can further enhance the structural stability and oxidation-reduction resistance of the sulfide solid electrolyte. Simultaneously, it can further improve the air stability and ionic conductivity of the sulfide solid electrolyte, thereby further enhancing the cycle life and voltage withstand performance of the all-solid-state lithium battery.

[0033] In one embodiment of this application, the chemical formula of the sulfide solid electrolyte is Li. 7+x-y P 1- x Eu x S 6-2x-y O 2x Cl 0.7y Br 0.3y 0.02≤x≤0.1, 1.25≤y≤1.4. Doping Eu at the P-sites and oxygen at the S-sites in the sulfide-germanium LPSC solid electrolyte, with x and y values ​​falling within the aforementioned ranges, can further enhance the structural stability and oxidation-reduction resistance of the sulfide solid electrolyte. Simultaneously, it can further improve the air stability and ionic conductivity of the sulfide solid electrolyte, thereby further enhancing the cycle life and voltage withstand performance of all-solid-state lithium batteries.

[0034] In one embodiment of this application, the chemical formula of the sulfide solid electrolyte is Li. 7+x-y P 1- x Pr x S 6-2x-y O 2x Cl 0.7y Br 0.3y0.02≤x≤0.1, 1.25≤y≤1.4. Doping Pr at the P sites and oxygen at the S sites in the sulfide-germanium LPSC solid electrolyte, with x and y values ​​falling within the aforementioned ranges, can further enhance the structural stability and oxidation-reduction resistance of the sulfide solid electrolyte. Simultaneously, it can further improve the air stability and ionic conductivity of the sulfide solid electrolyte, thereby further enhancing the cycle life and voltage withstand performance of all-solid-state lithium batteries.

[0035] In one embodiment of this application, the chemical formula of the sulfide solid electrolyte is Li. 7+x-y P 1- x Sm x S 6-2x-y O 2x Cl 0.7y Br 0.3y 0.02≤x≤0.1, 1.25≤y≤1.4. Doping Sm at the P-sites and oxygen at the S-sites in the sulfide-germanium LPSC solid electrolyte, with x and y values ​​falling within the aforementioned ranges, can further enhance the structural stability and oxidation-reduction resistance of the sulfide solid electrolyte. Simultaneously, it can further improve the air stability and ionic conductivity of the sulfide solid electrolyte, thereby further enhancing the cycle life and voltage withstand performance of the all-solid-state lithium battery.

[0036] In one embodiment of this application, the sulfide solid electrolyte is Li 5.77 P 0.98 Ce 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 Li 5.8 P 0.95 Ce 0.05 S 4.65 O 0.1 Cl 0.875 Br 0.375 Li 5.85 P 0.9 Ce 0.1 S 4.55 O 0.2 Cl 0.875 Br 0.375 Li 5.6 5P 0.95 Ce 0.05 S 4.5 O 0.1 Cl 0.98 Br 0.42 Li 5.77 P 0.98 Eu 0.02 S 4.71 O 0.04Cl 0.875 Br 0.375 Li 5.77 P 0.98 Pr 0.02 S 4.7 1O 0.04 Cl 0.875 Br 0.375 Li 5.77 P 0.98 Sm 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 The above-mentioned sulfide solid electrolytes offer higher structural stability, antioxidant capacity, air stability, and ionic conductivity.

[0037] In one embodiment of this application, the particle size of the sulfide solid electrolyte satisfies the following conditions: 0.5µm < D50 < 4µm, 7µm < D90 < 10µm. The particle size of the sulfide solid electrolyte in this application falls within the above range, resulting in good processability.

[0038] In one embodiment of this application, the ionic conductivity of the sulfide solid electrolyte is >8 mS / cm. Preferably, the ionic conductivity of the sulfide solid electrolyte is >9 mS / cm. The sulfide solid electrolyte of this application, while improving structural stability and air stability, also possesses high ionic conductivity, which can improve the electrochemical performance of all-solid-state lithium batteries when applied to them. It should be noted that the aforementioned "ionic conductivity of the sulfide solid electrolyte" refers to the ionic conductivity obtained by AC impedance spectroscopy testing after the sulfide solid electrolyte powder is pressurized and formed at 300 MPa.

[0039] This application does not impose any particular limitation on the preparation method of sulfide solid electrolyte, as long as it can achieve the purpose of this application. For example, the preparation method of sulfide solid electrolyte may include: mixing raw materials and solvent under an inert atmosphere to obtain a suspension; drying the suspension by vacuum distillation to obtain a solid electrolyte precursor mixture; and sintering the solid electrolyte precursor mixture to obtain the sulfide solid electrolyte.

[0040] This application does not impose special limitations on the types of raw materials and solvents, as long as they can achieve the purpose of this application. For example, the raw materials can be Li₂S, P₂S₅, LiCl, LiBr and rare earth oxides (e.g., CeO₂, PrO₂, Sm₂O₃, Eu₂O₃), and the solvents can be n-hexane, benzene, toluene, cyclohexane, n-pentane, cyclopentane, and dimethyl carbonate. In this application, the rare earth element M is doped into the P site in a tetravalent form, and with the pentavalent form... This leads to heterovalent substitution. To meet charge neutralization conditions and prevent the formation of secondary phases, the phosphorus source is typically reduced in the raw material ratio. The amount of phosphorus (P) fed in the reactor is adjusted, while the amounts of Ce, Pr, Sm, or Eu sources are appropriately increased to achieve partial substitution of P by Ce, Pr, Sm, or Eu. During this process, the amount of sulfur (S) fed in the reactor also needs to be adjusted accordingly to match the changes in the tetracoordination structure of the P sites. This is achieved by controlling... The molar ratio of rare earth elements to Ce, Pr, Sm, or Eu sources makes it more likely for them to enter the P site without generating excess byproducts, thus achieving stable P-site doping.

[0041] This application does not impose any particular limitation on the amount of raw materials and solvents added, as long as the purpose of this application is achieved. For example, the mass ratio of raw materials to solvent is 1:1 to 3. This application does not impose any particular limitation on the method of vacuum distillation drying, as long as the purpose of this application is achieved. For example, the vacuum distillation drying temperature is 40℃ to 60℃, and the vacuum degree is -0.09 MPa to -0.10 MPa. This application does not impose any particular limitation on the sintering method, as long as the purpose of this application is achieved. For example, a tube furnace programmed heating method is used, first heating at 150 to 300℃ for 2 to 4 hours, and then heating at 500 to 600℃ for 4 to 6 hours for sintering.

[0042] The second aspect of this application provides an all-solid-state lithium battery, which includes a positive electrode, a negative electrode, and a sulfide solid electrolyte as described in the first aspect of this application.

[0043] This application does not impose any particular limitations on the positive and negative electrodes in an all-solid-state lithium battery, as long as they achieve the purpose of this application. For example, the positive electrode includes a positive electrode active material, a sulfide solid electrolyte, and conductive carbon. The positive electrode active material can be a ternary positive electrode such as NCM523, NCM622, NCM712, NCM811, or NCM90, or it can be lithium iron phosphate or lithium manganese iron phosphate (LiMn). x Fe 1-x PO4, LiCoO2 materials, lithium-rich manganese-based materials (aLi2MnO3•(1-a)LiMO2) (0≤a≤1, M is at least one of Ni, Co or Mn), lithium nickel manganese oxide (LiNi 0.5 Mn 1.5 Materials such as O4, etc., the sulfide solid electrolyte is the electrolyte in this application, and the conductive carbon can be superconducting carbon black (Super P) or carbon black; the mass ratio of the positive electrode active material, the sulfide solid electrolyte, and the conductive carbon can be 60~80%:10~35%:3~10%. The negative electrode includes lithium indium alloy, lithium metal, graphite, and silicon carbon. Preferably, the all-solid-state lithium battery also includes a current collector disposed on the positive electrode material side; the current collector can be carbon-coated aluminum foil or pure aluminum foil.

[0044] This application does not impose any particular limitation on the preparation method of all-solid-state lithium batteries, as long as it can achieve the purpose of this application. For example, the preparation method of all-solid-state lithium batteries includes: mixing positive electrode active material, sulfide solid electrolyte and conductive carbon to obtain composite positive electrode powder; loading the sulfide solid electrolyte into a solid battery mold for a first pressing to obtain an electrolyte layer; adding the composite positive electrode powder to one side of the electrolyte layer for a second pressing to obtain a positive electrode; adding the negative electrode material to the other side of the electrolyte layer for a third pressing to obtain an all-solid-state lithium battery.

[0045] The sulfide solid electrolyte of this application has high ionic conductivity and air stability, and thus all-solid-state lithium batteries including the sulfide solid electrolyte of this application have excellent electrochemical performance.

[0046] Example

[0047] The embodiments and comparative examples provided below illustrate the implementation of this application in more detail. Various tests and evaluations were conducted according to the methods described below. Furthermore, unless otherwise specified, "parts" and "%" are quality standards.

[0048] Test methods and equipment:

[0049] Ion conductivity test

[0050] In an argon-filled glove box, 100 mg of sulfide solid electrolyte powder was weighed and placed in a mold battery (Wuhan Chuangneng CN-01) with stainless steel sheets with a diameter of 9 mm at both ends. The battery was then pressurized to 200 MPa and the electrolyte sheet thickness was 1 mm. The mold battery was then used for AC impedance spectroscopy testing.

[0051] In an argon-filled glove box, 110 mg of sulfide solid electrolyte powder was weighed and placed in a mold battery (Wuhan Chuangneng CN-01) with stainless steel sheets with a diameter of 9 mm at both ends. The battery was then pressurized to 300 MPa and the electrolyte sheet thickness was 1 mm. The mold battery was then used for AC impedance spectroscopy testing.

[0052] Electrochemical impedance spectroscopy (EIS) was performed at 25°C. The impedance was measured using a 1V DC polarization voltage applied to an electrochemical workstation (ChenHua, CHI630E) with an amplitude of 50mV and a frequency range of 1Hz to 10MHz. The ionic conductivity of the electrolyte material was calculated using the following formula:

[0053]

[0054] Where σ is the ionic conductivity, with units of S cm. –1L is the thickness of the electrolyte sheet, in cm; R is the electrolyte resistance, in Ω; S is the effective contact area between the stainless steel sheet and the electrolyte powder, in cm². 2 .

[0055] Air stability test

[0056] Air stability is primarily described by the retention of the ionic conductivity of the sulfide solid electrolyte and the amount of hydrogen sulfide generated when exposed to air.

[0057] Ion conductivity retention rate test: The ionic conductivity of the sulfide solid electrolyte was tested using the above-described ionic conductivity test method and recorded as the conductivity before exposure. Then, the sulfide solid electrolyte was directly exposed to air at 40% humidity and 25°C. The sulfide solid electrolyte was recovered after 10 minutes, 1 hour, and 24 hours, and the ionic conductivity was tested using the above-described ionic conductivity test method, recorded as the conductivity after exposure. Conductivity retention rate = Conductivity after exposure / Conductivity before exposure × 100%.

[0058] Hydrogen sulfide generation test: Under 40% air humidity and 25℃, a sulfide solid electrolyte of mass m and a hydrogen sulfide detector were placed together in a sealed reaction container of volume V. The container was ensured to be airtight. The reading of the hydrogen sulfide detector was recorded at fixed time intervals (every 30 seconds, for a total of 10 minutes) to obtain the gas concentration c after 10 minutes of exposure of the sulfide solid electrolyte. Based on the gas concentration c, the reaction container volume V, and the mass m of the sulfide solid electrolyte, the hydrogen sulfide generation per unit mass of sample was calculated. Hydrogen sulfide generation = (c × V) / m, in cm³. 3 / g.

[0059] X-ray powder diffraction test

[0060] X-ray powder diffraction (XRD) was used to analyze the crystal structure of the samples. A Bruker D8 Advance diffractometer equipped with Cu Kα radiation (λ = 1.5406 Å) as the light source was employed. The test parameters were set as follows: tube voltage 40 kV, tube current 40 mA, scanning range 2θ = 5°–90°, scanning step size 0.02°, and scanning rate 5° / min. The samples were uniformly dispersed in powder form on a glass slide without a diffraction background, and compaction was performed to reduce the influence of interparticle voids on the diffraction results.

[0061] Unit cell parameter analysis: XRD data were processed and analyzed using Jade software. First, the raw data was imported into the software, and after background subtraction and signal optimization, it was exported as a text file. The text file was then imported into the refinement software FullProf. An initial model was established based on the known crystal structure of the sample, and preliminary unit cell parameters and space group were input. Instrument parameters such as zero-point offset and sample displacement were adjusted to complete the initial fitting.

[0062] During the refinement process, peak shape parameters (such as peak width and peak shape factor), background functions, cell parameters (a, b, c, α, β, γ), and atomic positions and occupancy are gradually optimized to achieve final convergence of the fit. The fitting results are evaluated based on the goodness of fit Chi2, while the residual spectrum is used to determine the quality of the fit. Once the refinement results converge (Chi2 < 3), the cell parameters a, b, and c can be obtained from the software's output text.

[0063] Particle size distribution testing

[0064] The surface morphology and particle size distribution of the sulfide solid electrolyte were observed using a Zeiss Sigma 300 scanning electron microscope (SEM). The microscope was fixed on the sample stage, which was placed in a vacuum chamber. The accelerating voltage, beam current, and working distance of the SEM were adjusted to optimize the imaging effect. Surface morphology information was acquired using a secondary electron detector. The particle size of the sulfide solid electrolyte in the SEM images was measured and statistically analyzed using ImageJ software to obtain its particle size distribution.

[0065] Electrochemical performance testing

[0066] Electrochemical performance testing mainly involves assembling a solid-state battery with a sulfide solid electrolyte and a layered high-nickel NCM811 ternary cathode material.

[0067] Preparation of all-solid-state battery: (1) Preparation of positive electrode material: NCM811 positive electrode active material, sulfide solid electrolyte of this application and conductive carbon are mixed in a mass ratio of 75:20:5 and ground in a mortar for 30 minutes to obtain composite positive electrode powder; (2) Negative electrode material: lithium indium alloy (lithium content is 30wt%); (3) Sulfide solid electrolyte: sulfide solid electrolyte of this application is used; (4) Assembly of all-solid-state battery: In a glove box filled with argon gas, 100mg of sulfide solid electrolyte is weighed first. The electrolyte layer was obtained by adding it into a solid-state battery mold with an inner diameter of 10 mm and pressurizing it to 300 MPa for 1 minute. 10 mg of composite positive electrode powder was added to one side of the electrolyte layer and covered with 15 µm aluminum foil. The pressure was increased to 100 MPa and held for 1 minute to obtain the positive electrode. Then, 100 µm of lithium indium alloy negative electrode material was added to the other side. After slight pressure of 50 MPa, the mold was assembled to obtain the assembled all-solid-state lithium-ion battery. After verifying the airtightness, it was taken out of the glove box and transferred to the battery testing system for electrochemical charge-discharge cycle testing.

[0068] Charge and discharge test: The charge and discharge performance of the battery is tested using the LAND battery testing system under a constant temperature of 25°C.

[0069] Constant current charge-discharge testing directly reflects the electrochemical performance of active materials in a battery and is an important means of evaluating the practical application potential of these materials. In the test, the current density is based on the material mass, and the specific capacity corresponding to 1C is defined as 120. 0.2C is equivalent to 24. During the 0.2C rate cycling process, the battery is first charged from 2.6V to a preset cutoff voltage (3.9V, 4.0V, 4.1V, 4.2V, 4.3V, or 4.4V) using a constant current. The highest voltage at which the battery can operate stably is selected as the cutoff voltage. Then, the battery is discharged to 2.6V using the same current. The entire process is completed in constant current mode. The capacity retention rate (first-time effect) of the all-solid-state lithium-ion battery during the first charge-discharge process at 0.2C, the capacity retention rate after 200 cycles during the 0.2C charge-discharge cycle, and the number of cycles of the all-solid-state lithium-ion battery when the discharge capacity drops sharply (in this application, a sudden and drastic drop in discharge capacity refers to a sudden and rapid decrease in discharge capacity) are recorded.

[0070] The specific capacity during the first charge and discharge cycle of a battery is used to calculate the first discharge efficiency (first efficiency), which is calculated as follows: First efficiency = First discharge capacity / First charge capacity × 100%. This indicator can be used to evaluate the capacity loss caused by irreversible reactions (such as electrolyte decomposition or solid electrolyte interfacial film formation) that occur in the material during the first cycle.

[0071] Capacity retention rate after 200 cycles = (200th discharge capacity / first discharge capacity) × 100%.

[0072] Example 1

[0073] In an Ar atmosphere, raw materials of Li₂S, P₂S₅, LiCl, LiBr, and rare earth oxide CeO₂ in a molar ratio of 2.275:0.475:0.875:0.375:0.05 were weighed. 1 kg of the raw material was mixed with 1 kg of n-hexane to obtain a suspension. The suspension was dried by vacuum distillation at 40°C and a vacuum of -0.098 MPa to obtain a solid electrolyte precursor mixture. In an Ar atmosphere, using a tubular furnace with programmed heating, the obtained solid electrolyte precursor mixture was first heated at 200°C for 3 hours, then at 550°C for 5 hours to obtain a sulfide solid electrolyte (Li₂S₅:P₂S₅:LiCl:LiBr:CeO₂). 5.8 P 0.95 Ce 0.05 S 4.6 5O 0.1 Cl 0.875 Br 0.375 Its X-ray diffraction pattern is as follows: Figure 1 As shown.

[0074] Examples 2 to 7

[0075] Except for adjusting the molar ratio of the raw materials to obtain sulfide solid electrolytes with different chemical formulas as shown in Table 1, the remaining steps are the same as in Example 1.

[0076] Example 8

[0077] By replacing the raw materials with "Li₂S, P₂S₅, LiCl, LiBr, P₂O₅, elemental S and rare earth oxide Eu₂O₃ in a molar ratio of 2.26:0.488:0.875:0.375:0.002:0.01:0.01", a sulfide solid electrolyte (Li₂S, P₂S₅, LiCl, LiBr, P₂O₅, elemental S and rare earth oxide Eu₂O₃) is obtained. 5.77 P 0.9 8Eu 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 Except for the step described in Example 1, the remaining steps are the same. Its X-ray diffraction pattern is as follows: Figure 2 As shown.

[0078] Example 9

[0079] By replacing the raw materials with "Li₂S, P₂S₅, LiCl, LiBr and rare earth oxide PrO₂ in a molar ratio of 2.26:0.49:0.875:0.375:0.02", a sulfide solid electrolyte (Li₂S, P₂S₅, LiCl, LiBr and rare earth oxide PrO₂) was obtained. 5.77 P 0.98 Pr0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 Except for the step described in Example 1, the remaining steps are the same. Its X-ray diffraction pattern is as follows: Figure 3 As shown.

[0080] Example 10

[0081] By replacing the raw materials with "Li₂S, P₂S₅, LiCl, LiBr, P₂O₅, elemental S and rare earth oxide Sm₂O₃ in a molar ratio of 2.26:0.488:0.875:0.375:0.002:0.01:0.01", a sulfide solid electrolyte (Li₂S, P₂S₅, LiCl, LiBr, P₂O₅, elemental S and rare earth oxide Sm₂O₃) is obtained. 5.77 P 0.9 8Sm 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 Except for the step described in Example 1, the remaining steps are the same. Its X-ray diffraction pattern is as follows: Figure 4 As shown.

[0082] Example 11

[0083] By replacing the raw materials with "Li₂S, P₂S₅, LiCl, LiI and rare earth oxide CeO₂ in a molar ratio of 2.275:0.475:0.875:0.375:0.05", a sulfide solid electrolyte (Li₂S, P₂S₅, LiCl, LiI and rare earth oxide CeO₂) was obtained. 5.8 P 0.95 Ce 0.05 S 4.65 O 0.1 Cl 0.875 I 0.375 Except for the steps in Example 1, the remaining steps are the same.

[0084] Example 12

[0085] By replacing the raw materials with "Li₂S, P₂S₅, LiBr, LiI and rare earth oxide CeO₂ in a molar ratio of 2.275:0.475:0.875:0.375:0.05", a sulfide solid electrolyte (Li₂S, P₂S₅, LiBr, LiI and rare earth oxide CeO₂) was obtained. 5.8 P 0.95 Ce 0.05 S 4.65 O 0.1 Br 0.875 I 0.375 Except for the steps in Example 1, the remaining steps are the same.

[0086] Example 13

[0087] By replacing the raw materials with "Li₂S, P₂S₅, LiCl, LiBr, LiI and rare earth oxide CeO₂ in a molar ratio of 2.275:0.475:0.875:0.25:0.125:0.05", a sulfide solid electrolyte (Li₂S, P₂S₅, LiCl, LiBr, LiI and rare earth oxide CeO₂) was obtained. 5.8 P 0.95 Ce 0.05 S 4.65 O 0. 1Cl 0.875 Br 0.25 I 0.125 Except for the steps in Example 1, the remaining steps are the same.

[0088] Example 14

[0089] By replacing the raw materials with "Li₂S, P₂S₅, LiCl and rare earth oxide CeO₂ in a molar ratio of 2.275:0.475:1.25:0.05", a sulfide solid electrolyte (Li₂S, P₂S₅, LiCl and rare earth oxide CeO₂) was obtained. 5.8 P 0.95 Ce 0.05 S 4.65 O 0.1 Cl 1.25 Except for the steps in Example 1, the remaining steps are the same.

[0090] Example 15

[0091] The raw materials were replaced with a mixture of Li₂S, P₂S₅, LiCl, LiBr, CeO₂ oxide, P₂O₅, elemental S, and rare earth oxide Eu₂O₃ in a molar ratio of 2.26:0.489:0.875:0.375:0.01:0.001:0.005:0.005 to obtain a sulfide solid electrolyte (Li₂S, P₂S₅, LiCl, LiBr, CeO₂ oxide, P₂O₅, elemental S, and rare earth oxide Eu₂O₃). 5.77 P 0.98 Ce 0.01 Eu 0.01 S 4.71 O 0.04 Cl 0.875 Br 0.375 Except for the steps in Example 1, the remaining steps are the same.

[0092] Example 16

[0093] By replacing the raw materials with "Li₂S, P₂S₅, LiCl, LiBr and rare earth oxide CeO₂ in a molar ratio of 2.275:0.475:0.625:0.625:0.05", a sulfide solid electrolyte (Li₂S, P₂S₅, LiCl, LiBr and rare earth oxide CeO₂) was obtained. 5.8 P 0.95 Ce 0.05 S 4.65 O 0.1 Cl 0.625 Br0.625 Except for the steps in Example 1, the remaining steps are the same.

[0094] Example 17

[0095] The sulfide solid electrolyte is the same as in Example 1, and the positive electrode active material used for electrochemical performance testing is Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2, the negative electrode material is graphite, and the remaining electrochemical performance testing steps are the same as the above testing methods.

[0096] Example 18

[0097] The sulfide solid electrolyte is the same as in Example 1, and the positive electrode active material used for electrochemical performance testing is LiFe. 0.5 Mn 0.5 PO4, with silicon-carbon as the negative electrode material, and the remaining electrochemical performance testing procedures are the same as those described above.

[0098] Comparative Examples 1 to 5

[0099] Except for adjusting the molar ratio of the raw materials to obtain sulfide solid electrolytes with different chemical formulas as shown in Table 1, the remaining steps are the same as in Example 1.

[0100] Comparative Example 6

[0101] By replacing the raw materials with a molar ratio of Li₂S, P₂S₅, LiCl, and LiBr of 2.25: 0.5: 0.875: 0.375, a sulfide solid electrolyte (Li₂S, P₂S₅, LiCl, and LiBr) was obtained. 5.75 PS 4.75 Cl 0.875 Br 0.375 Except for the step described in Example 1, the remaining steps are the same. Its X-ray diffraction pattern is as follows: Figure 5 As shown.

[0102] Comparative Example 7

[0103] By replacing the raw materials with "Li₂S, P₂S₅, LiCl, LiBr, and CeS₂ in a molar ratio of 2.275: 0.475: 0.875: 0.375: 0.05", a sulfide solid electrolyte (Li₂S₅) is obtained. 5.8 P 0.95 Ce 0.05 S 4.75 Cl 0.875 Br 0.375 Except for the steps in Example 1, the remaining steps are the same.

[0104] Comparative Example 8

[0105] Besides adjusting the molar ratio of the raw materials, a sulfide solid electrolyte (Li) is obtained. 5.76 P 0.99 Ce 0.01 S 4.75 Cl 0.875 Br 0.3 75 Except for ), the remaining steps are the same as those in Comparative Example 6.

[0106] Comparative Example 9

[0107] By replacing the raw materials with "Li₂S, P₂S₅, LiCl, LiBr, P₂O₅ in a molar ratio of 2.25: 0.48: 0.875: 0.375: 0.02", a sulfide solid electrolyte (Li₂S, P₂S₅, LiCl, LiBr, P₂O₅) is obtained. 5.75 PS 4.65 O 0.1 Cl 0.875 Br 0.375 Except for the steps in Example 1, the remaining steps are the same.

[0108] Comparative Example 10

[0109] Besides adjusting the molar ratio of the raw materials, a sulfide solid electrolyte (Li) is obtained. 5.75 PS 4.73 O 0.02 Cl 0.875 Br 0.375 Except for ), the rest are the same as Comparative Example 8.

[0110] Comparative Example 11

[0111] By replacing the raw materials with "Li₂S, P₂S₅, LiCl and rare earth oxide CeO₂ in a molar ratio of 1.91:0.49:1.6:0.02", a sulfide solid electrolyte (Li₂S, P₂S₅, LiCl and rare earth oxide CeO₂) was obtained. 5.42 P 0.98 Ce 0.02 S 4.36 O 0.04 Cl 1.6 Except for the steps in Example 1, the remaining steps are the same.

[0112] Comparative Example 12

[0113] By replacing the raw materials with "Li₂S, P₂S₅, LiCl, SnS₂, CeO₂ in a molar ratio of 2.25:0.35:1.4:0.2:0.1", a sulfide solid electrolyte (Li₂S₅) was obtained. 5.9 P 0.7 Sn 0.2 Ce 0.1 S 4.4 O 0.2 Cl 1.4Except for the steps in Example 1, the remaining steps are the same.

[0114] The preparation parameters and performance parameters of the sulfide solid electrolytes of each embodiment and comparative example are shown in Table 1, and the performance parameters of the all-solid-state batteries obtained therefrom are shown in Tables 2 and 3.

[0115] Table 1. Preparation and performance parameters of sulfide solid electrolytes

[0116]

[0117] In Table 1, " / " indicates that there are no relevant parameters.

[0118] Table 2 Performance parameters of all-solid-state batteries

[0119]

[0120] Table 3 Performance parameters of all-solid-state batteries of different systems

[0121]

[0122] As can be seen from Table 1, the sulfide solid electrolyte of this application satisfies the chemical formula Li 7+x-y P 1-x M x S 6-2x- y O 2x X y M is at least one of the variable-valence rare earth elements Ce, Eu, Pr, and Sm, and X is at least one halogen. The valences are 0.002 ≤ x ≤ 0.3 and 0.5 ≤ y ≤ 1.4. The resulting sulfide solid electrolyte cell parameters satisfy a = b = c = 9.85~10 Å. The particle size of the sulfide solid electrolyte satisfies 0.5 µm < D50 < 4 µm and 7 µm < D90 < 10 µm. The sulfide solid electrolyte exhibits high ionic conductivity and air stability. [The last sentence appears to be incomplete and requires further context.] After being pressurized at 300 MPa, the material was subjected to AC impedance spectroscopy testing. The results showed that the ionic conductivity of the sulfide solid electrolyte was >8 mS / cm. The conductivity retention rate was ≥75% after 10 minutes of exposure to 40% air humidity, ≥63% after 1 hour of exposure to 40% air humidity, and ≥40% after 24 hours of exposure to 40% air humidity. The hydrogen sulfide generation was <0.049 cm⁻¹ after 10 minutes of exposure to 40% air humidity. 3 / g. As shown in Table 2, the sulfide solid electrolyte of this application, when used in all-solid-state lithium batteries, can improve the initial discharge efficiency, cycle performance, and cutoff voltage of the all-solid-state lithium batteries. Its initial discharge efficiency is ≥70.2%, capacity retention after 200 cycles at 0.2C is ≥95.3%, the number of cycles at 0.2C is ≥303, and the cutoff voltage is ≥4.1V, thus improving the initial efficiency, cycle life, and voltage withstand performance of the all-solid-state lithium battery. As shown in Table 3, the sulfide solid electrolyte of this application, when applied to all-solid-state lithium batteries of different systems, results in all-solid-state lithium batteries with high initial discharge efficiency, good cycle performance, and high cutoff voltage. In summary, the sulfide solid electrolyte of this application enhances the structural stability and oxidation-reduction resistance of the sulfide solid electrolyte, while also improving its air stability and ionic conductivity, thereby achieving a longer cycle life and stronger voltage withstand performance in all-solid-state lithium batteries.

[0123] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A sulfide solid electrolyte, characterized in that, The sulfide solid electrolyte has the chemical formula Li. 7+x-y P 1- x M x S 6-2x-y O 2x X y M is at least one of the variable-valence rare earth elements Ce, Eu, Pr and Sm, X is at least one of the halogens, 0.002≤x≤0.3, 0.5≤y≤1.4, and the molar ratio of element M to element O is 1:2; The unit cell parameters of the sulfide solid electrolyte satisfy: a=b=c=9.85~10Å, and the ionic conductivity of the sulfide solid electrolyte is >8mS / cm.

2. The sulfide solid electrolyte according to claim 1, characterized in that, 0.02≤x≤0.1, 1.25≤y≤1.

4.

3. The sulfide solid electrolyte according to claim 1, characterized in that, X is at least one of Cl, Br, and I.

4. The sulfide solid electrolyte according to claim 1, characterized in that, The chemical formula of the sulfide solid electrolyte is Li 7+x-y P 1-x M x S 6-2x-y O 2x X' 0.7y X'' 0.3y X' or X'' is independently Cl, Br or I, and X' is different from X'', with X' having a smaller ionic radius than X''.

5. The sulfide solid electrolyte according to claim 1, characterized in that, The chemical formula of the sulfide solid electrolyte is Li 7+x-y P 1-x M x S 6-2x-y O 2x Cl 0.7y Br 0.3y .

6. The sulfide solid electrolyte according to claim 1, characterized in that, The sulfide solid electrolyte is Li 5.77 P 0.98 Ce 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 Li 5.8 P 0.95 Ce 0.05 S 4.65 O 0.1 Cl 0.875 Br 0.375 Li 5.85 P 0.9 Ce 0. 1S 4.55 O 0.2 Cl 0.875 Br 0.375 Li 5.65 P 0.95 Ce 0.05 S 4.5 O 0.1 Cl 0.98 Br 0.42 Li 5.77 P 0.98 Eu 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 Li 5.77 P 0.98 Pr 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 Li 5.77 P 0.98 Sm 0.02 S 4.71 O 0.04 Cl 0.875 Br 0.375 .

7. The sulfide solid electrolyte according to claim 1, characterized in that, The particle size of the sulfide solid electrolyte satisfies the following conditions: 0.5µm < D50 < 4µm, 7µm < D90 < 10µm.

8. An all-solid-state lithium battery, comprising a positive electrode, a negative electrode, and a sulfide solid electrolyte as described in any one of claims 1 to 7.

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