Solid electrolyte material and preparation method therefor, solid electrolyte, semi-solid electrolyte, positive electrode, and battery

Abstract

A solid electrolyte material and a preparation method therefor, a solid electrolyte, a semi-solid electrolyte, a positive electrode, and a battery. The solid electrolyte material comprises a compound represented by the following general formula: Aa(M1bM2c)Xd, wherein A comprises one or more of Li, Na, K, Cu and Ag, X is halogen, M1 is a main element, M1 is selected from among one of Ga, Y, In, Mg, Sr, Sc, Al, Fe, Zr, Hf, Ta, Nb, W, Mn, Zn, Co, Mo, Sn, Ca, Pb, Ti, Ru and a lanthanide metal element, M2 is a doping element, M2 comprises one or more elements of groups IIA, IIB, IIIA, IIIB, IVA, IVB, VA and VB, b is greater than the molar ratio of any element in M2, 0.5≤a≤5, 0.2≤b≤2, 0.2≤c≤2, d=a*ε1+b*ε2+c*ε3, ε1 is the weighted average valence of A, ε2 is the weighted average valence of M1, and ε3 is the weighted average valence of M2.

Description

Solid electrolyte material and preparation method thereof, solid electrolyte, semi-solid electrolyte, positive electrode and battery

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to a Chinese patent application filed with the Patent Office of China on January 26, 2024, with application number 202410112507.X and application name “A solid electrolyte material and its preparation method, solid electrolyte, semi-solid electrolyte, positive electrode and battery”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present invention belongs to the technical field of solid-state batteries, and specifically relates to a solid electrolyte material and a preparation method thereof, a solid electrolyte, a semi-solid electrolyte, a positive electrode and a battery. Background Art

[0004] Currently, solid-state batteries have become a hot topic in the research field of energy storage devices such as lithium batteries and sodium batteries due to their high energy density and excellent safety. Solid-state electrolytes are a key component of solid-state batteries. In addition to traditional inorganic solid-state electrolyte materials, halogen solid-state electrolytes have become a new research focus due to their unique chemical and physical properties. Halogen solid-state electrolytes generally have good ionic conductivity and stable chemical properties, making them potential applications in the field of high-performance batteries. In particular, halogen electrolytes have shown excellent interfacial stability and high electrical conductivity in lithium batteries and other solid-state battery systems.

[0005] However, traditional halogen solid electrolytes still face challenges in terms of electrical conductivity, mechanical properties and thermal stability. Among the metal halide electrolytes that have been widely studied, chlorides and bromides with high ionic conductivity have poor electrochemical stability and a very limited electrochemical window. In contrast, fluorine-based solid electrolytes with the widest electrochemical window and excellent air stability have low room temperature ionic conductivity, which limits their application. Further improving the ionic conductivity of fluoride electrolytes can enable them to be coupled with positive electrodes with high voltages above 5V. Moreover, according to some current research results, the grain boundary resistance of halogen solid electrolytes cannot be ignored, and the various interfaces (grain boundaries, positive electrode-electrolyte interface and electrolyte-negative electrode interface) present in solid-state batteries will hinder their practical application.

[0006] Existing halogen solid electrolytes mainly focus on simple components, such as ternary halide systems, but these systems generally fail to meet the high comprehensive performance requirements required for industrial applications, such as high electrochemical stability, a wide electrochemical window, high ionic conductivity, and low interfacial resistance. Therefore, the exploration of new halogen solid electrolytes, especially those that can achieve a better balance between ionic conductivity, mechanical properties, and thermal stability, has become an important topic in research and industry.

[0007] Summary of the Invention

[0008] In view of the problem of low ion conductivity of existing halogen solid electrolyte materials, the present invention provides a solid electrolyte material and a preparation method thereof, a solid electrolyte, a semi-solid electrolyte, a positive electrode and a battery.

[0009] The technical solutions adopted by the present invention to solve the above technical problems are as follows:

[0010] In one aspect, the present invention provides a solid electrolyte material comprising a compound represented by the following general formula:

[0011] A a (M1 b M2 c )X d

[0012] Wherein, A includes one or more of Li, Na, K, Cu, and Ag, X is a halogen, M1 is a main element, M1 is selected from Ga, Y, In, Mg, Sr, Sc, Al, Fe, Zr, Hf, Ta, Nb, W, Mn, Zn, Co, Mo, Sn, Ca, Pb, Ti, Ru, and one of the lanthanide metal elements, M2 is a doping element, M2 includes one or more of Group IIA, IIB, IIIA, IIIB, IVA, IVB, VA, and VB elements, M1 and M2 are different, and b is greater than the molar ratio of any element in M2, 0.5≤a≤5, 0.2≤b≤2, 0.2≤c≤2, and d=a*ε1+b*ε2+c*ε3, wherein ε1 is the weighted average valence of A, ε2 is the weighted average valence of M1, and ε3 is the weighted average valence of M2.

[0013] Optionally, M2 includes one or more of Mg, Zn, Al, Sc, Ga, Y, In, Zr, Hf, Sb, Bi, and lanthanide elements.

[0014] Optionally, M1 is selected from one of Ga, Y, In, Mg, Sr, Sc, Al, Fe, Zr, Hf, Ta, Nb, W, Mn, Zn, Co, Mo, Sn, Ca, Pb, Ti, Ru and lanthanide metal elements, and M2 is selected from at least four of Mg, Zn, Al, Sc, Ga, Y, In, Zr, Hf, Sb, Bi and lanthanide elements.

[0015] Optionally, the M1 and the M2 have different valences.

[0016] Optionally, X includes one or more of F, Cl, Br and I.

[0017] Optionally, the A is selected from one or more of Li and Na.

[0018] Optionally, the A is selected from one or more of Cu and Ag.

[0019] Optionally, the solid electrolyte material is in granular form with a particle size of 1 nm to 10 μm.

[0020] Optionally, the solid electrolyte material is selected from Li3Y 0.3 In 0.1 Er 0.2 Yb 0.2 Zr 0.2 Cl 6.2 、Li3Y 0.3 In 0.1 Er 0.2 Yb 0.2 Zr 0.3 Cl 6.6 、Li 0.388 Nb 0.238 La 0.475 Cl3、Li 0.447 Ta 0.179 Zr 0.059 La 0.475 Cl3、Li 0.495 Zr 0.259 Ca 0.086 La 0.432 Cl3、Li 0.388 Ta 0.238 Ce 0.475 Cl3、Li 0.388 Ta 0.238 Nd 0.475 Cl3、Li 0.388 Ta 0.238 Gd 0.475 Cl3、Li3Yb 0.8 Zr 0.2 Cl 6.2 .

[0021] In another aspect, the present invention provides a method for preparing the solid electrolyte material as described above, comprising the following steps:

[0022] The solid electrolyte material is prepared by using LiX, M1X and M2X as raw materials through grinding or solvent co-dissolution and recrystallization.

[0023] Optional steps include:

[0024] The raw materials AX and M1X are mixed and ground once to obtain a solid electrolyte precursor;

[0025] M2X is added to the solid electrolyte precursor and subjected to secondary grinding to obtain the solid electrolyte material.

[0026] Optionally, the grinding is ball milling, the ball-to-material ratio is 15:1 to 25:1, the ball milling time is 3 to 10 hours, and the ball milling speed is 400 to 600 rpm.

[0027] Optionally, the residual alkali in the raw materials AX, M1X, and M2X is controlled to be less than or equal to 0.01 ppm.

[0028] Optionally, the raw materials AX, M1X, and M2X are dried before the first grinding.

[0029] Optionally, the drying method includes one or more of vacuum heating treatment, rotary evaporation drying treatment, vacuum freeze drying treatment or microwave vacuum drying treatment.

[0030] In another aspect, the present invention provides a solid electrolyte comprising the solid electrolyte material as described above.

[0031] In another aspect, the present invention provides a semi-solid electrolyte, characterized in that it comprises an electrolyte and the solid electrolyte material as described above.

[0032] In another aspect, the present invention provides a positive electrode, comprising a positive electrode material layer, wherein the positive electrode material layer comprises a positive electrode active material and the solid electrolyte material as described above.

[0033] Optionally, based on the total mass of the positive electrode material layer being 100%, the mass percentage of the positive electrode active material is 50% to 99%, and the mass percentage of the solid electrolyte material is 0.5% to 49.5%.

[0034] On the other hand, the present invention provides a battery comprising a positive electrode, an electrolyte and a negative electrode, wherein the positive electrode is selected from the positive electrode described above, and / or the electrolyte is selected from the solid electrolyte described above or the semi-solid electrolyte described above.

[0035] According to the solid electrolyte material provided by the present invention, the metal other than the carrier A in the halide solid electrolyte material is divided into a main element M1 and a doping element M2. The solid electrolyte material formed by M1 and M2 replacing the carrier A forms a certain cation vacancy, and the solid electrolyte material can maintain a stable crystal structure under high voltage, has high electrochemical stability, and at the same time has high entropy characteristics, reduces the formation of crystal boundaries, and reduces grain boundary resistance; and M1 is the main element, and a high-abundance, easily accessible metal raw material can be selected, and M2 is a doping element, which can reduce the amount of high-cost and difficult-to-obtain rare metals, thereby reducing material costs while improving the ionic conductivity of the solid electrolyte material. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] One embodiment of the present invention provides a solid electrolyte material, including a compound represented by the following general formula:

[0038] A a (M1 b M2 c )X d

[0039] Wherein, A includes one or more of Li, Na, K, Cu, and Ag, X is a halogen, M1 is a main element, M1 is selected from Ga, Y, In, Mg, Sr, Sc, Al, Fe, Zr, Hf, Ta, Nb, W, Mn, Zn, Co, Mo, Sn, Ca, Pb, Ti, Ru, and a lanthanide metal element, M2 is a doping element, M2 includes one or more of Group IIA, IIB, IIIA, IIIB, IVA, IVB, VA, and VB elements, M1 and M2 are different, and b is greater than the molar ratio of any element in M2, 0.5≤a≤5, 0.2≤b≤2, 0.2≤c≤2, and d=a*ε1+b*ε2+c*ε3, wherein ε1 is the weighted average valence of A, ε2 is the weighted average valence of M1, and ε3 is the weighted average valence of M2.

[0040] In the description of the present invention, the term "molar ratio of any element in M2" refers to the molar ratio of any element in M2 in compound A. a (M1 b M2 c )X d The molar ratio subscript in the , for example, when A a (M1 b M2 c )X d Li3Y 0.3 In 0.1 Er 0.2 Yb 0.2 Zr 0.2 Cl 6.2 , the molar ratio of Y is the largest, so Y is M1, and In, Er, Yb, and Zr are M2. At this time, the molar ratio of In is 0.1, the molar ratio of Er is 0.2, the molar ratio of Yb is 0.2, and the molar ratio of Zr is 0.2.

[0041] The metals other than the carrier A in the halide solid electrolyte material are divided into a main element M1 and a doping element M2. The solid electrolyte material formed by M1 and M2 replacing the carrier A forms a certain cation vacancy, and the solid electrolyte material can maintain a stable crystal structure under high voltage, has high electrochemical stability, and has high entropy characteristics, reduces the formation of crystal boundaries, and reduces grain boundary resistance; and M1 is the main element, and a high-abundance, easily accessible metal raw material can be selected, and M2 is a doping element, which can reduce the amount of high-cost and difficult-to-obtain rare metals, thereby reducing material costs while improving the ionic conductivity of the solid electrolyte material.

[0042] Compared with existing solid electrolyte materials, the solid electrolyte material provided by the present invention has the following advantages:

[0043] 1) High-entropy strategies can enhance the ionic conductivity of solid-state electrolytes, thereby reducing the dependence on specific chemicals and enhancing synthesizability.

[0044] 2) In multi-component electrolytes, multiple different ions coexist, allowing them to find energy-minimizing states in a wider range of chemical compositions and structural configurations than traditional materials. As a result, these materials exhibit better thermodynamic stability under a variety of temperature and pressure conditions.

[0045] 3) The multi-element characteristics of multi-component solid electrolytes can better match the chemical and physical properties of electrode materials, reducing the mismatch between solid electrolyte materials and electrodes, which can significantly reduce interfacial impedance and improve the transmission efficiency of electrons and ions.

[0046] 4) The introduction of multiple metal ions increases the disorder of the multi-component electrolyte’s crystal structure, making it more resistant to deformation while also improving its resistance to impact and compression. This enhanced mechanical stability reduces the impact of physical deformation during battery operation.

[0047] 5) The multi-component system of multi-component electrolytes helps to dilute and evenly distribute potential active sites, reducing the localized tendency of chemical reactions, which helps to reduce chemical decomposition and side reactions and improve the chemical stability of the material.

[0048] In the description of the present invention, the term "weighted average valence" refers to the a (M1 b M2 c )X d The weighted average valence of the same element in the compound. For example, when A is selected from Li ions, its weighted average valence is 1. When Li is selected from Li ions and Cu ions with equal coordination numbers, its weighted average valence is (1+2) / 2=1.5.

[0049] In some embodiments, the M2 includes one or more of Mg, Zn, Al, Sc, Ga, Y, In, Zr, Hf, Sb, Bi, and lanthanide elements.

[0050] When the main element M2 is selected from the metal elements described above, a crystal structure with a large number of cation vacancies can be formed, thereby facilitating the conduction of lithium ions in the solid electrolyte material and improving the ionic conductivity of the solid electrolyte material.

[0051] In some embodiments, M1 is selected from one of Ga, Y, In, Mg, Sr, Sc, Al, Fe, Zr, Hf, Ta, Nb, W, Mn, Zn, Co, Mo, Sn, Ca, Pb, Ti, Ru and lanthanide metal elements, and M2 is selected from at least four of Mg, Zn, Al, Sc, Ga, Y, In, Zr, Hf, Sb, Bi and lanthanide elements.

[0052] By employing a single metal element as the primary metal (M1), the stability of the solid electrolyte material's main structure and the uniformity of the material are ensured. The introduction of multiple elements (M2)—at least five doping elements—increases the system entropy of the solid electrolyte material. The localized distortion of the high-entropy material leads to overlapping potential energy distributions of charge carriers (A), enabling their transport with low activation energy. The chemical disorder introduced by the high entropy and the resulting distortions locally disrupt the site energies, resulting in a distribution of site energies. When this distribution is wide enough for the energies of adjacent sites to overlap, it promotes ion hopping between them, further reducing grain boundary resistance and improving the ionic conductivity of the solid electrolyte material.

[0053] In some embodiments, the M1 and the M2 have different valencies.

[0054] Doping with heterovalent metal elements can make the A element and the M1 and M2 elements have a suitable atomic ratio and appropriate doping concentration, introduce an appropriate amount of cation vacancies while retaining the mobile A cations, and improve the crystal structure stability of the solid electrolyte material during the charge and discharge cycle.

[0055] In some embodiments, X comprises one or more of F, Cl, Br, and I.

[0056] In some embodiments, the halogen includes two or more of F, Cl, Br and I. The doping of multiple halogens causes mixed anions, allowing lithium ions to migrate through the energy band gaps formed by different anion radii, thereby facilitating the improvement of ion conduction efficiency.

[0057] In some embodiments, the A is selected from one or more of Li and Na.

[0058] In some embodiments, the A is selected from one or more of Cu and Ag.

[0059] Cu and / or Ag are used as the carrier A of the solid electrolyte material, and the ionic conductivity of the solid electrolyte material can be improved through a multiple substitution strategy.

[0060] In some embodiments, the solid electrolyte material is in granular form with a particle size of 1 nm to 10 μm. In some embodiments, the solid electrolyte material is selected from Li3Y 0.3 In 0.1 Er 0.2 Yb 0.2 Zr 0.2 Cl 6.2 、Li3Y 0.3 In 0.1 Er 0.2 Yb 0.2 Zr 0.3 Cl 6.6 、Li 0.388 Nb 0.238 La 0.475 Cl3、Li 0.447 Ta 0.179 Zr 0.059 La 0.475 Cl3、Li 0.495 Zr 0.259 Ca 0.086 La 0.432 Cl3、Li 0.388 Ta 0.238 Ce 0.475 Cl3、Li 0.388 Ta 0.238 Nd 0.475 Cl3、Li 0.388 Ta 0.238 Gd 0.475 Cl3、Li3Yb 0.8 Zr 0.2 Cl 6.2 .

[0061] The preparation process of existing solid electrolyte materials is complicated and has high requirements on equipment and operation. To address this problem, the solid electrolyte materials provided by the present invention provide a variety of simplified synthesis processes, specifically:

[0062] Some embodiments of the present invention provide a method for preparing the solid electrolyte material as described above, comprising the following steps:

[0063] The solid electrolyte material is prepared by using LiX, M1X and M2X as raw materials through grinding or solvent co-dissolution and recrystallization.

[0064] In one embodiment of the present invention, the method for preparing the solid electrolyte material as described above comprises the following steps:

[0065] The raw materials AX, M1X and M2X are uniformly mixed and then ground to obtain the solid electrolyte material.

[0066] In another embodiment of the present invention, the method for preparing the solid electrolyte material as described above comprises the following steps:

[0067] The raw materials AX, M1X and M2X are mixed uniformly and then ground, and the ground product is solid-phase sintered to obtain the solid electrolyte material.

[0068] In another embodiment of the present invention, the method for preparing the solid electrolyte material as described above comprises the following steps:

[0069] The raw materials AX, M1X and M2X are mixed uniformly and then solid-phase sintered to obtain the solid electrolyte material.

[0070] In some embodiments, the solid-phase sintering process is performed under one or more conditions of vacuum, Ar atmosphere, or HCl atmosphere, the solid-phase sintering temperature is 150-600° C., and the solid-phase sintering time is 0.5-200 h.

[0071] In some embodiments, the solid-phase sintering temperature is 180-320° C., and the solid-phase sintering time is 2-12 hours.

[0072] In another embodiment of the present invention, the method for preparing the solid electrolyte material as described above comprises the following steps:

[0073] The raw materials AX, M1X and M2X are put into a solvent together, and the solid electrolyte material is obtained by a solvent co-dissolution recrystallization method.

[0074] In another embodiment of the present invention, the method for preparing the solid electrolyte material as described above comprises the following steps:

[0075] The raw materials AX, M1X and M2X are mixed uniformly and then ground, and then added into a solvent together, and the solid electrolyte material is obtained by a solvent co-dissolution recrystallization method.

[0076] In some embodiments, the solvent is selected from water, alcohols, or hydrohalic acids.

[0077] In some embodiments, a hydrolysis inhibitor is added to the organic solvent, and the hydrolysis inhibitor includes NH4X (X is a halogen) or ammonia water.

[0078] In some embodiments, the solid electrolyte material obtained by the solvent co-dissolution recrystallization method is filtered and dried.

[0079] The above-provided method for preparing the solid electrolyte material reduces the production steps, reduces the dependence on equipment precision and operation complexity, and is conducive to large-scale production.

[0080] In another embodiment of the present invention, the method for preparing the solid electrolyte material comprises the following steps:

[0081] The raw materials AX and M1X are mixed and ground once to obtain a solid electrolyte precursor;

[0082] M2X is added to the solid electrolyte precursor and subjected to secondary grinding to obtain the solid electrolyte material.

[0083] In the above preparation methods, the raw materials AX, M1X and M2X are added together. However, the inventors found in the test that adding the raw materials AX, M1X and M2X together cannot achieve the ideal state. Through further research on the preparation method, it was found that when the raw materials AX and M1X are first used to prepare a solid electrolyte precursor, and then M2X is used for doping treatment, the obtained solid electrolyte material has better electrochemical properties. This is because during the synthesis process, the M1 element occupies the A element site in the AX lattice and introduces a large number of cation vacancies. The local distortion caused by the introduction of the M2 element leads to the potential energy overlap of the A cations, thereby improving the ion conductivity of the solid electrolyte material. The ion mixing caused by the simultaneous addition of AX, M1X and M2X makes it difficult to achieve such ion conductivity; and the high-energy environment in the first grinding process can further remove residual water and residual alkali on the surface of the raw materials, and can reveal fresh crystal faces of the materials, which is conducive to the generation of highly mixed products in the secondary grinding reaction.

[0084] In some embodiments, the grinding is ball milling, the ball-to-material ratio is 15:1 to 25:1, the ball milling time is 3 to 10 hours, and the ball milling speed is 400 to 600 rpm.

[0085] Through a large number of experiments, the inventors found that solid electrolyte materials cannot maintain a good dry environment during the actual production process. The surface of the solid electrolyte material will react with water and CO2 in the air to generate alkaline substances such as LiOH and Li2CO3. Trace water and residual alkali will cause the solid electrolyte material to decompose under high pressure, resulting in degradation of the electrochemical properties of the solid electrolyte material. To address this problem, in some embodiments, in the preparation method of the solid electrolyte material, the residual alkali content in the raw materials AX, M1X, and M2X is controlled to be less than or equal to 0.01ppm.

[0086] In some embodiments, the raw materials AX, M1X, and M2X are dried before the first grinding.

[0087] Drying treatment is a control method for reducing the water content in the raw materials, and is used to control the free water or crystal water content in the raw materials AX, M1X, and M2X to be lower than or equal to 0.01 ppm; it should be noted that when the free water or crystal water content in the raw materials AX, M1X, and M2X is lower than or equal to 0.01 ppm, no additional drying treatment is required for the raw materials.

[0088] In some embodiments, the drying method includes one or more of vacuum heating treatment, rotary evaporation drying treatment, vacuum freeze drying treatment, or microwave vacuum drying treatment.

[0089] In some embodiments, when the drying treatment is a vacuum heating treatment, the temperature of the vacuum heating treatment is 40-120°C, the heating rate is 0.1-5°C / min, the cooling rate is 0.5-5°C / min, the time is 3-24h, and the vacuum degree is -0.1-0MPa g.

[0090] In a preferred embodiment, the vacuum heating treatment is performed at a temperature of 80 to 100° C. for a time of 6 to 12 hours.

[0091] In some embodiments, when the drying process is a rotary evaporation drying process, the temperature of the rotary evaporation drying process is 40 to 100° C., and the time is 4 to 16 hours.

[0092] In a preferred embodiment, the rotary evaporation drying process is carried out at a temperature of 80 to 100° C. and for a time of 6 to 12 hours.

[0093] In some embodiments, when the drying treatment is a vacuum freeze-drying treatment, the temperature of the vacuum freeze-drying treatment is -40 to -10°C, the time is 6 to 24 hours, and the vacuum degree is -0.1 to 0 MPa g.

[0094] In a preferred embodiment, the vacuum freeze-drying treatment is performed at a temperature of -40 to -30°C for 6 to 12 hours.

[0095] In some embodiments, when the drying treatment is a microwave vacuum drying treatment, the power of the microwave vacuum drying treatment is 400 to 2000 W, the time is 3 to 24 hours, and the vacuum degree is -0.1 to 0 MPa g.

[0096] Another embodiment of the present invention provides a solid electrolyte comprising the solid electrolyte material as described above.

[0097] The solid electrolyte prepared using the solid electrolyte material described above has high ionic conductivity and electrochemical stability, which is beneficial for reducing battery impedance and extending the cycle life of the battery.

[0098] The present invention provides a semi-solid electrolyte comprising an electrolyte and the solid electrolyte material as described above.

[0099] In some embodiments, based on the total mass of the semi-solid electrolyte being 100%, the mass percentage of the electrolyte is 0.5 wt %-50 wt %, and the electrolyte includes a lithium salt, a solvent, and optional additives.

[0100] Specifically, the solvent may include carbonates (e.g., ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-butyrolactone (BL)), ethers (e.g., tetrahydrofuran (THF), 2-methyl-tetrahydrofuran (2-Me-THF), dimethoxydimethyl ether (DMM), 1,2-dimethoxyethane (DME), 1,3-dioxolane (DOL), nitriles (e.g., acetonitrile (AN)), etc.);

[0101] Lithium salts may include lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), other organic lithium salts (such as lithium trifluoromethanesulfonate (LiCF3SO), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethylsulfonyl-perfluorobutylsulfonylimide (LiTNFSI), lithium fluorosulfonyl-perfluorobutylsulfonylimide (LiFNFSI), lithium bis(oxalatoborate) (LiBOB), tris(trifluoromethylsulfonyl)methyllithium (LiC(SO2CF3)3), etc.).

[0102] Additives may include film-forming additives, conductive additives, flame retardant additives, overcharge protection additives, water and HF content control additives (i.e., additives that control the water and HF content in the electrolyte), low-temperature additives (i.e., general additives that improve low-temperature performance), and may also include negative electrode stabilizers, i.e., additives that improve the interface stability of the metallic lithium negative electrode (such as fluoroethylene carbonate (FEC), lithium nitrate (LiNO3), etc.).

[0103] Another embodiment of the present invention provides a positive electrode, including a positive electrode material layer, wherein the positive electrode material layer includes a positive electrode active material and the solid electrolyte material as described above.

[0104] By doping the positive electrode material layer with a solid electrolyte material, the ionic conductivity of the positive electrode material layer can be effectively improved, the internal resistance of the positive electrode material layer can be reduced, and the rate performance can be improved.

[0105] In some embodiments, based on the total mass of the positive electrode material layer being 100%, the mass percentage of the positive electrode active material is 50% to 99%, and the mass percentage of the solid electrolyte material is 0.5% to 49.5%.

[0106] In some embodiments, the positive electrode active material includes lithium nickel cobalt manganese oxide (N x M y C z ,x+y+z=1)、Lithium manganese iron phosphate (LiFe x Mn y PO4, x+y=1), one or more of lithium iron phosphate, lithium manganate, lithium cobaltate, lithium nickelate, lithium-rich manganese-based, lithium nickel manganate (LMNO), and lithium vanadium phosphate (Li3V2(PO4)3, LiVOPO4).

[0107] In some embodiments, the positive electrode material layer further includes a positive electrode binder and a positive electrode conductor, and the positive electrode active material, the solid electrolyte material, the positive electrode binder and the positive electrode conductor are blended to obtain the positive electrode material layer.

[0108] The positive electrode binder is selected from a polymer resin having adhesive properties, and the positive electrode conductor is selected from a carbon material.

[0109] Another embodiment of the present invention provides a battery comprising a positive electrode, an electrolyte and a negative electrode, wherein the positive electrode is selected from the positive electrode described above, and / or the electrolyte is selected from the solid electrolyte described above or the semi-solid electrolyte described above.

[0110] In some embodiments, the negative electrode is selected from one or more of graphite, silicon oxide, silicon carbon, silicon, tin, tin oxide, tin alloys (Sn-Fe, Sn-Co, Sn-Cu, etc.), lithium metal, lithium alloys (Li-Ag, Li-Al, Li-Sn, Li-Mg, Li-Zn, Li-In, Li-Ga, etc.) and lithium-free negative electrodes.

[0111] In some embodiments, the battery is an all-solid-state battery or a semi-solid-state battery.

[0112] The present invention is further described below with reference to the following examples.

[0113] Example 1

[0114] This embodiment is used to illustrate the preparation method of the solid-state battery disclosed in the present invention, which includes the following steps:

[0115] Preparation of solid electrolyte particles: LiCl, YbCl3 and ZrCl4 are used as raw materials, wherein the molar ratio of LiCl, YbCl3 and ZrCl4 is 3:0.8:0.2. The raw materials are vacuum heated to detect the water content of the raw materials to be less than 0.01ppm and the residual alkali content to be less than 0.01ppm. The raw materials LiCl and YbCl3 are mixed and ball milled once to obtain a solid electrolyte precursor; ZrCl4 is added to the solid electrolyte precursor and ball milled twice to obtain the solid electrolyte material Li3Yb 0.8 Zr 0.2 Cl 6.2 .

[0116] Preparation of solid electrolyte: The solid electrolyte material is placed in a mold and pressed into a tablet to obtain a solid electrolyte.

[0117] Preparation of solid-state batteries: lithium cobalt oxide is used as the positive electrode and graphite is used as the negative electrode. The positive electrode, negative electrode and solid electrolyte are assembled to form a solid-state battery.

[0118] Example 2

[0119] This example is used to illustrate the method for preparing a solid-state battery disclosed in the present invention, and includes most of the steps in Example 1, except that:

[0120] In the preparation of solid electrolyte particles, LiCl, YCl3, InCl3, ErCl3, YbCl3, and ZrCl4 are used as raw materials, wherein the molar ratio of LiCl, YCl3, InCl3, ErCl3, YbCl3, and ZrCl4 is 3:0.3:0.1:0.2:0.2:0.2. The raw materials LiCl and YCl3 are mixed and ball-milled once to obtain a solid electrolyte precursor; InCl3, ErCl3, YbCl3, and ZrCl4 are added to the solid electrolyte precursor and ball-milled twice to obtain the solid electrolyte material Li3Y 0.3 In 0.1 Er 0.2 Yb 0.2 Zr 0.2 Cl 6.2 .

[0121] Example 3

[0122] This example is used to illustrate the method for preparing a solid-state battery disclosed in the present invention, and includes most of the steps in Example 1, except that:

[0123] In the preparation of solid electrolyte particles, LiCl, LaCl3, and NbCl3 are used as raw materials, wherein the molar ratio of LiCl, LaCl3, and NbCl3 is 0.388:0.475:0.238. The raw materials LiCl and LaCl3 are mixed and ball-milled once to obtain a solid electrolyte precursor; NbCl3 is added to the solid electrolyte precursor and ball-milled twice to obtain the solid electrolyte material Li. 0.388 La 0.475 Nb 0.238 Cl3.

[0124] Example 4

[0125] This example is used to illustrate the method for preparing a solid-state battery disclosed in the present invention, and includes most of the steps in Example 1, except that:

[0126] In the preparation of solid electrolyte particles, LiCl, TaCl3, ZrCl4, and LaCl3 are used as raw materials, wherein the molar ratio of LiCl, TaCl3, ZrCl4, and LaCl3 is 0.44:0.179:0.059:0.475. The raw materials LiCl and LaCl3 are mixed and ball-milled once to obtain a solid electrolyte precursor; TaCl3 and ZrCl4 are added to the solid electrolyte precursor and ball-milled twice to obtain the solid electrolyte material Li. 0.447 Ta 0.179 Zr 0.059 La 0.475 Cl3.

[0127] Example 5

[0128] This example is used to illustrate the method for preparing a solid-state battery disclosed in the present invention, and includes most of the steps in Example 1, except that:

[0129] In the preparation of solid electrolyte particles, LiCl, YCl3, InCl3, ErCl3, YbCl3, and ZrCl4 are used as raw materials, wherein the molar ratio of LiCl, YCl3, InCl3, ErCl3, YbCl3, and ZrCl4 is 3:0.3:0.1:0.2:0.2:0.2. The raw materials LiCl and YCl3 are mixed and ball-milled once to obtain a solid electrolyte precursor; InCl3, ErCl3, YbCl3, and ZrCl4 are added to the solid electrolyte precursor and ball-milled twice to obtain the solid electrolyte material Li3Y 0.3 In 0.1 Er 0.2 Yb 0.2 Zr 0.2 Cl 6.2 .

[0130] Example 6

[0131] This example is used to illustrate the method for preparing a solid-state battery disclosed in the present invention, and includes most of the steps in Example 1, except that:

[0132] In the preparation of solid electrolyte particles, LiCl, YCl3, InCl3, ErCl3, YbCl3, and ZrCl4 are used as raw materials, wherein the molar ratio of LiCl, YCl3, InCl3, ErCl3, YbCl3, and ZrCl4 is 3:0.3:0.1:0.2:0.2:0.3. The raw materials LiCl and YCl3 are mixed and ball-milled once to obtain a solid electrolyte precursor; InCl3, ErCl3, YbCl3, and ZrCl4 are added to the solid electrolyte precursor and ball-milled twice to obtain the solid electrolyte material Li3Y 0.3 In 0.1 Er 0.2 Yb 0.2 Zr 0.3 Cl 6.6 .

[0133] Example 7

[0134] This example is used to illustrate the method for preparing a solid-state battery disclosed in the present invention, and includes most of the steps in Example 1, except that:

[0135] The raw materials LiCl, YbCl3 and ZrCl4 are not subjected to vacuum heating treatment. After testing, the residual water and residual alkali in the raw materials are greater than 100 ppm.

[0136] Example 8

[0137] This example is used to illustrate the method for preparing a solid-state battery disclosed in the present invention, and includes most of the steps in Example 1, except that:

[0138] In the preparation of solid electrolyte particles, the raw materials LiCl, YbCl3 and ZrCl4 are mixed and ball-milled to obtain the solid electrolyte material Li3Yb 0.8 Zr 0.2 Cl 6.2 .

[0139] Example 9

[0140] This embodiment is used to illustrate the preparation method of the solid-state battery disclosed in the present invention, which includes the following steps:

[0141] LiCl, YbCl3 and ZrCl4 are used as raw materials, wherein the molar ratio of LiCl, YbCl3 and ZrCl4 is 3:0.8:0.2, the raw materials are vacuum heated, and the water content and residual alkali content in the raw materials are detected to be less than 0.01ppm and less than 0.01ppm, the raw materials LiCl, YbCl3 and ZrCl4 are put into an organic solvent, and then heated to evaporate the organic solvent to precipitate solid electrolyte particles, filter, wash with organic solvent, and dry to obtain the solid electrolyte material Li3Yb 0.8 Zr 0.2 Cl 6.2 .

[0142] Preparation of solid electrolyte: The solid electrolyte material is placed in a mold and pressed into a tablet to obtain a solid electrolyte.

[0143] Preparation of solid-state batteries: lithium cobalt oxide is used as the positive electrode and graphite is used as the negative electrode. The positive electrode, negative electrode and solid electrolyte are assembled to form a solid-state battery.

[0144] Comparative Example 1

[0145] This example is used to illustrate the method for preparing a solid-state battery disclosed in the present invention, and includes most of the steps in Example 1, except that:

[0146] Preparation of solid electrolyte particles: LiCl and InCl3 are used as raw materials, wherein the molar ratio of LiCl to InCl3 is 3:1. The raw materials are vacuum heated to detect the water content and hydroxyl content in the raw materials to be less than 0.01ppm and less than 0.01ppm, and the raw materials LiCl and InCl3 are mixed and ball milled to obtain the solid electrolyte material Li3InCl6.

[0147] Performance Testing

[0148] The solid-state battery prepared above was subjected to the following performance tests:

[0149] Cycle life test:

[0150] Use 0.3Cmin current to charge the battery cell to the upper cut-off voltage, the cut-off current is 0.05Cmin, and record the first cycle charging capacity Q 充1 , discharge at a current of 1Cmin until the battery voltage reaches the lower cut-off voltage, and record the discharge capacity Q 放1 The first cycle Coulomb efficiency is Q 放1 / Q 充1 Repeated cycle, battery cycle life is less than 80% discharge capacity·Q 放1 The test results are entered in Table 1.

[0151] Table 1

[0152] The test results in Table 1 show that Examples 1-6 and Example 9 achieve higher first-cycle Coulombic efficiencies (90%-91%) than Examples 7 and 8 (82% and 84%), and also exhibit longer cycle life. This suggests that heating the raw materials and removing residual water and alkali through a two-step ball milling process contribute to improved product performance. Furthermore, compared to Comparative Example 1, the Examples exhibit superior first-cycle Coulombic efficiencies and cycle life.

[0153] Comparing the test results of the first cycle storage efficiency and cycle life, it can be seen that the solid electrolyte proposed in the present invention has good comprehensive performance.

[0154] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A solid electrolyte material, characterized in that, Comprising a compound represented by the following general formula: A a (M1 b M2 c )X d Among them, A includes one or more of Li, Na, K, Cu, and Ag, X is a halogen, M1 is the main element, M1 is selected from one of Ga, Y, In, Mg, Sr, Sc, Al, Fe, Zr, Hf, Ta, Nb, W, Mn, Zn, Co, Mo, Sn, Ca, Pb, Ti, Ru, and lanthanide metal elements, M2 is a doping element, M2 includes one or more of the elements in Group IIA, IIB, IIIA, IIIB, IVA, IVB, VA, and VB, M1 and M2 are different, and b is greater than the molar ratio of any element in M2, 0.5 ≤ a ≤ 5, 0.2 ≤ b ≤ 2, 0.2 ≤ c ≤ 2, d = a*ε1 + b*ε2 + c*ε3, where ε1 is the weighted average valence of A, ε2 is the weighted average valence of M1, and ε3 is the weighted average valence of M2.

2. The solid electrolyte material according to claim 1, wherein The M2 includes one or more of Mg, Zn, Al, Sc, Ga, Y, In, Zr, Hf, Sb, Bi, and lanthanide elements.

3. The solid electrolyte material according to claim 2, wherein The M1 is selected from one of Ga, Y, In, Mg, Sr, Sc, Al, Fe, Zr, Hf, Ta, Nb, W, Mn, Zn, Co, Mo, Sn, Ca, Pb, Ti, Ru, and lanthanide metal elements, and the M2 is selected from at least 4 of Mg, Zn, Al, Sc, Ga, Y, In, Zr, Hf, Sb, Bi, and lanthanide elements.

4. The solid electrolyte material according to claim 1, wherein The M1 and the M2 have different valences.

5. The solid electrolyte material according to claim 1, characterized in that, The X includes one or more of F, Cl, Br, and I.

6. The solid electrolyte material according to claim 1, wherein The A is selected from one or more of Li and Na.

7. The solid electrolyte material according to claim 1, characterized in that The A is selected from one or more of Cu and Ag.

8. The solid electrolyte material according to claim 1, characterized in that, The solid electrolyte material is granular, and the particle size is 1 nm to 10 μm.

9. The solid electrolyte material according to claim 1, wherein The solid electrolyte material is selected from Li3Y 0.3 In 0.1 Er 0.2 Yb 0.2 Zr 0.2 Cl 6.2 、Li3Y 0.3 In 0.1 Er 0.2 Yb 0.2 Zr 0.3 Cl 6.6 、Li 0.388 Nb 0.238 La 0.475 Cl3、Li 0.447 Ta 0.179 Zr 0.059 La 0.475 Cl3、Li 0.495 Zr 0.259 Ca 0.086 La 0.432 Cl3、Li 0.388 Ta 0.238 Ce 0.475 Cl3、Li 0.388 Ta 0.238 Nd 0.475 Cl3、Li 0.388 Ta 0.238 Gd 0.475 Cl3 and Li3Yb 0.8 Zr 0.2 Cl 6.2 or one or more of them.

10. The preparation method of the solid electrolyte material according to any one of claims 1 to 9, characterized in that, It includes the following operation steps: Using LiX, M1X, and M2X as raw materials, the solid electrolyte material is prepared by grinding or solvent co - dissolution and recrystallization.

11. The preparation method of the solid electrolyte material according to claim 10, wherein, It includes the following operation steps: Mix the raw materials AX and M1X and conduct primary grinding to obtain a solid electrolyte precursor; Add M2X to the solid electrolyte precursor and conduct secondary grinding to obtain the solid electrolyte material.

12. The method for preparing the solid electrolyte material according to claim 11, wherein The grinding is ball milling, the ball - to - material ratio is 15:1 to 25:1, the ball milling time is 3 to 10 h, and the ball milling speed is 400 to 600 rpm.

13. The preparation method of the solid electrolyte material according to claim 11, characterized in that, Control the residual alkali in the raw materials AX, M1X, and M2X to be less than or equal to 0.01 ppm.

14. The method for preparing the solid electrolyte material according to claim 13, wherein Before the primary grinding, the raw materials AX, M1X, and M2X are dried.

15. The preparation method of the solid electrolyte material according to claim 14, characterized in that, The methods of the drying treatment include one or more of vacuum heating treatment, rotary evaporation drying treatment, vacuum freeze - drying treatment, or microwave vacuum drying treatment.

16. A solid electrolyte, characterized in that, It includes the solid electrolyte material as described in any one of claims 1 - 9.

17. A semi-solid electrolyte, characterized in that, It includes an electrolyte solution and the solid electrolyte material as described in any one of claims 1 - 9.

18. A positive electrode, characterized in that, It includes a positive electrode material layer, and the positive electrode material layer includes a positive electrode active material and the solid electrolyte material as described in any one of claims 1 - 9.

19. The positive electrode according to claim 18, wherein Based on the total mass of the positive electrode material layer being 100%, the mass percentage content of the positive electrode active material is 50% to 99%, and the mass percentage content of the solid electrolyte material is 0.5% to 49.5%.

20. A battery, characterized in that, It includes a positive electrode, an electrolyte, and a negative electrode. The positive electrode is selected from the positive electrode as described in claim 18 or 19, and / or the electrolyte is selected from the solid electrolyte as described in claim 16 or the semi-solid electrolyte as described in claim 17.

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