Preparation and application of high-entropy lithium argyrodite sulfide solid electrolyte

Abstract

Preparation and application of a high-entropy lithium argyrodite sulfide solid electrolyte. The structural formula of the high-entropy sulfide electrolyte is Li θ M α N β P 1‑α‑β S 4.5‑λ X λ Y 1.5 , wherein 5.32 < θ < 6.46, 0.01 ≤ α < 0.32, 0.01 ≤ β < 0.32 and 0 < α + β ≤ 0.32, 0 < λ ≤ 0.5. In the sulfide solid electrolyte prepared by doping elements with different properties, the introduction of metal cations can produce additional lithium vacancies, increase the freedom of lithium ion migration, and improve the ionic conductivity; the introduction of soft acid cations can form a stable tetrahedral structure, improving air stability; the introduction of inorganic anions can form a stable interface layer in situ at the lithium negative electrode, hindering the contact between the electrolyte and the lithium negative electrode, and improving the stability of the negative electrode interface; and the introduction of halogen anions can adjust the degree of internal atomic disorder, increase the configurational entropy of the material, thereby reducing the diffusion energy barrier of lithium ions and improving the ionic conductivity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid electrolytes, and particularly relates to preparation and application of a high-entropy lithium argyrodite sulfide solid electrolyte. BACKGROUND

[0002] With the rapid development of portable electronic devices, electric vehicles and renewable energy storage systems, the current society has an increasing demand for battery technologies with high performance, low cost and long service life. Although traditional liquid electrolytes can meet the performance requirements of lithium batteries, their inherent safety problems, insufficient low-temperature performance and the bottleneck of full battery energy density limit their further development. In particular, in high-energy density application scenarios, the flammability and leakage risk of liquid electrolytes are major safety hazards. In addition, the interface stability between liquid electrolytes and lithium metal anodes is poor, and uneven lithium deposition leads to the formation of dendrites, which poses a risk of battery short circuit and failure. Full solid-state batteries, which use solid electrolytes, can theoretically solve the safety problems of liquid electrolytes, have higher energy density, a wider working temperature range and a longer service life, and are widely considered an important development direction for future battery technologies. Compared with liquid electrolytes, solid electrolytes are not flammable, have high mechanical strength and can effectively inhibit the growth of lithium dendrites. However, the key to realizing this technology lies in the development of solid electrolyte materials with high ionic conductivity and good stability.

[0003] Sulfide solid electrolytes have received extensive attention in recent years, mainly because they have an ionic conductivity of up to 10 —3 ~10 —2 S / cm at room temperature, which is comparable to that of liquid electrolytes. In addition, sulfide electrolytes generally have a wide electrochemical window and good mechanical flexibility, which enables them to form good interface contact when matched with electrode materials. However, traditional sulfide solid electrolytes have poor chemical stability and are extremely sensitive to water molecules in the air. This instability not only limits their application in actual battery systems, but also increases the cost of material preparation and processing. In addition, the synthesis process of such materials is complex and usually involves high-temperature sintering or expensive raw materials, further increasing their production cost.

[0004] Introducing the concept of high-entropy materials into the design of sulfide solid electrolytes can effectively overcome the above challenges. High-entropy materials form a highly disordered crystal structure through the uniform mixing of multiple elements. High-entropy sulfide materials, especially high-entropy lithium argyrodite structures, have unique structural disorder that can effectively maintain high ionic conductivity while enhancing their chemical and electrochemical stability. In addition, by introducing specific elements to improve their resistance to water molecules in the air, their stability in practical applications can be significantly improved.

[0005] Another significant advantage of high-entropy materials is its stability at the battery interface. In solid-state batteries, the interface stability between the electrolyte and the electrode material is crucial to the electrochemical performance of the full battery. Due to the diversity of its composition and the complexity of its structure, high-entropy sulfide can form a more uniform and stable SEI layer at the interface, hindering the further decomposition of the electrolyte, which is of great significance to improve the interface stability.

[0006] In summary, the development of high-entropy lithium argyrodite-type sulfide solid electrolyte materials not only can significantly improve the overall performance of full solid-state batteries, but also will help to promote the large-scale popularization of full solid-state battery technology in practical applications. The success of this innovative technology will provide key technical support for the next generation of high-safety, high-energy-density energy storage systems, with wide industrial application prospects and significant social and economic benefits. SUMMARY

[0007] The purpose of the present application is to prepare a high-entropy lithium argyrodite-type sulfide solid electrolyte with excellent performance to solve the problems existing in the prior art.

[0008] Based on the above purpose, the present application adopts the following technical solution:

[0009] The present application is a high-entropy lithium argyrodite-type sulfide solid electrolyte with high ionic conductivity, high air stability, stable electrochemical performance, and excellent interface stability, which is prepared by multi-site doping according to the different physical properties of elements.

[0010] A high-entropy lithium argyrodite-type sulfide solid electrolyte, characterized in that the chemical formula of the solid electrolyte material is:

[0011] Li θ M α N β P 1-α-β S 4.5-λ X λ Y 1.5 ;

[0012] Wherein, M is any two or more of Al, Si, Ge, Ti, Mn elements, N is any two or more of Mg, Zn, In, Cu, Sn, Bi, Sb elements, X is any two or more of F, O, N, Se, Te elements, Y is any one or more of Cl, Br, I three elements; in the chemical formula, 5.32 < θ < 6.46, 0.01 ≤ α < 0.32, 0.01 ≤ β < 0.32, and 0 < α + β ≤ 0.32, 0 < λ ≤ 0.5.

[0013] The preparation method of the high-entropy lithium argyrodite-type sulfide solid electrolyte as described above, characterized in that it comprises the following steps:

[0014] 1) According to the target chemical formula, the required Li source compound, M source compound, N source compound, X source compound and Y source compound are subjected to drying treatment;

[0015] 2) The raw materials after drying in step 1) are weighed and mixed under the protection of inert atmosphere according to the required mass calculated according to the molar ratio of the electrolyte chemical formula, to obtain a mixed material precursor;

[0016] 3) The mixed material precursor obtained in step 2) is subjected to ball milling and tabletting process treatment to obtain a tablet precursor;

[0017] 4) The tablet precursor obtained in step 3) is subjected to high-temperature heat treatment, and after cooling to room temperature, it is ground into a powder under the protection of inert atmosphere to obtain a high-entropy sulfide solid electrolyte material.

[0018] Further, the Li source compound in the step 1) includes two or more of Li2S, Li3P, Li3N, Li2O, LiF, LiCl, LiBr, and LiI; the M source compound includes two or more of AlF3, Al2O3, AlN, AlCl3, AlBr3, AlI3, SiO2, SiS2, Si3N4, SiSe2, SiTe2, GeO2, Ge3N4, GeSe2, GeTe2, TiO2, TiSe2, TiTe2, MnF2, MnO2, Mn3N2, MnSe, MnTe, MnCl2, MnBr2, and MnI2; the N source compound includes two or more of MgF2, MgO, Mg3N2, MgSe, MgTe, MgCl2, MgBr2, MgI2, ZnF2, ZnO, Zn3N2, ZnSe, ZnTe, ZnCl2, ZnBr2, ZnI2, InF3, In2O3, InN, In2Se3, In2Te3, InCl3, InBr3, and InI3; the Cu source compound includes two or more of CuF2, CuO, Cu3N2, CuSe, CuTe, CuCl2, CuBr2, and CuI2; the Sn source compound includes two or more of SnF4, SnO2, Sn3N4, SnCl4, SnSe2, and SnTe2; the Bi source compound includes two or more of BiF3, Bi2O3, BiN, Bi2Se3, Bi2Te3, BiCl3, BiBr3, and BiI3; the Sb source compound includes two or more of SbF3, Sb2O3, Sb2Se3, and Sb2Te3; the P source includes one or more of P, P2S5, P4S9, P4S5, and P4S6; the S source includes one or more of S, Li2S, P2S5, P4S9, P4S5, and P4S6; the X source compound includes two or more of LiF, AlF3, Al2O3, AlN, SiO2, Si3N4, SiSe2, SiTe2, GeO2, Ge3N4, GeSe2, GeTe2, TiO2, TiSe2, TiTe2, MnF2, MnO2, Mn3N2, MnSe, MnTe, MgF2, MgO, Mg3N2, MgSe, MgTe, ZnF2, ZnO, Zn3N2, ZnSe, ZnTe, InF3, In2O3, InN, In2Se3, In2Te3, CuF2, CuO, Cu3N2, CuSe, CuTe, SnF4, SnO2, Sn3N4, SnCl4, SnSe2, SnTe2, BiF3, Bi2O3, BiN, Bi2Se3, Bi2Te3, SbF3, Sb2O3, Sb2Se3, and Sb2Te3; and the Y source compound includes one or more of LiCl, LiBr, and LiI.

[0019] Further, the drying treatment in the step 1) is performed at 60-80°C for 10-12 hours under vacuum.

[0020] Further, the step 2) after weighing and mixing needs to use a marver, and grinding and mixing are performed for 10-20 min.

[0021] Further, the step 3) of the mixed material precursor is subjected to a dry ball milling process, and high-energy ball milling is used for mixing, the rotation speed of the ball mill is 400-600 rpm / min, the ball milling time is 8-12 h, the ball-to-material ratio is 20:1, and the mass ratio of large ball milling beads to small ball milling beads is 1:1.

[0022] Further, the step 3) of the mixed material precursor is subjected to a dry ball milling process, and high-energy ball milling is used for mixing, the rotation speed of the ball mill is 400-600 rpm / min, the ball milling time is 8-12 h, the ball-to-material ratio is 20:1, and the mass ratio of large ball milling beads to small ball milling beads is 1:1.

[0023] Further, the step 4) of the tablet-shaped precursor is subjected to a high-temperature treatment process, and the process conditions include: a heat treatment temperature of 400-600 ℃, a heat treatment time of 6-8 h, and a heating rate of 1-5 ℃ / min; and the cooling rate to room temperature is 10-20 ℃ / min.

[0024] The application of the high-entropy lithium argyrodite-type sulfide solid electrolyte material prepared according to the method described above is applied to a full-solid-state lithium battery.

[0025] Further, the full-solid-state lithium battery comprises a composite positive electrode layer, a sulfide electrolyte layer and a lithium negative electrode / composite negative electrode layer.

[0026] The composite positive electrode layer and the sulfide electrolyte layer comprise the high-entropy lithium argyrodite-type sulfide solid electrolyte material obtained by the preparation process described above.

[0027] The application advantages of the cation and anion co-doped high-entropy lithium argyrodite-type sulfide solid electrolyte material of the application are as follows:

[0028] 1) By introducing heterovalent metal cations into the argyrodite-type sulfide electrolyte, additional lithium vacancies can be generated in the structure, the concentration of lithium ion carriers is significantly increased, the freedom of lithium ion migration is increased, the migration path of lithium ions is optimized, and the ionic conductivity of the electrolyte body is improved;

[0029] 2) The introduction of soft acid cations into the argyrodite-type sulfide electrolyte can promote the formation of strong covalent bonds between soft alkali S and the structure, thereby forming a stable tetrahedron, and when in contact with water molecules in the air, the combination of soft alkali S elements and H elements is effectively inhibited, thereby protecting the structural stability of the sulfide electrolyte and improving the air stability;

[0030] 3) Doping inorganic anions in argyrodite sulfide electrolyte can improve the interface stability between electrolyte and lithium metal. In the cycle process, a stable interface layer is formed in situ between electrolyte and lithium metal, which hinders the contact between sulfide electrolyte and lithium metal, further inhibits the side reaction at the interface, protects the structure of sulfide electrolyte, and improves the stability of lithium metal negative electrode interface;

[0031] 4) Introducing multiple halogen anions in argyrodite sulfide electrolyte can improve the configurational entropy of the material, and the disorder degree of anions can be improved by adjusting the types of halogen ions in the structure. The disordered structure increases the sublattice near the lithium ion, reduces the diffusion energy barrier of lithium ion, and further improves the ionic conductivity of sulfide;

[0032] The preparation method of the high-entropy lithium argyrodite sulfide electrolyte material provided by the application is a dry process, which has the advantages of safety and environmental protection compared with a wet process, and the use of organic solvents is avoided to reduce production cost.

[0033] The high-entropy lithium argyrodite sulfide electrolyte prepared by the high-temperature heat treatment process has extremely high ionic conductivity, can meet the use requirements of most batteries, and has simple preparation process, low raw material cost, high yield of electrolyte material, and wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical scheme of the embodiments of the application, the drawings in the embodiments of the application will be briefly introduced below.

[0035] Figure 1 It is an SEM morphology diagram of Example 1;

[0036] Figure 2 It is an XRD characteristic spectrum of Example 1;

[0037] Figure 3 It is an impedance curve diagram of Example 1;

[0038] Figure 4 It is a full battery cycle diagram of Example 1;

[0039] Figure 5 It is a H2S release amount statistical diagram of Example 1;

[0040] Figure 6 It is an SEM morphology diagram of Comparative Example 1;

[0041] Figure 7 It is an XRD characteristic spectrum of Comparative Example 1;

[0042] Figure 8Impedance curve diagram of Comparative Example 1;

[0043] Figure 9 Full cell cycle diagram of Comparative Example 1;

[0044] Figure 10 H2S release amount statistical diagram of Comparative Example 1. DETAILED DESCRIPTION

[0045] The application provides a preparation process and application of a high-entropy lithium argyrodite sulfide electrolyte material.

[0046] The application adopts a strategy of co-doping of cations and anions to prepare a high-entropy lithium argyrodite sulfide solid electrolyte material, which has a chemical formula of Li θ M α N β P 1-α-β S 4.5-λ X λ Y 1.5 , wherein 5.32 < θ < 6.46, 0.01 ≤ α < 0.32, 0.01 ≤ β < 0.32 and 0 < α + β ≤ 0.32, and 0 < λ ≤ 0.5. The electrolyte material has high ionic conductivity, high air stability, stable electrochemical performance and excellent interface stability.

[0047] Example 1

[0048] The application provides a preparation process of a high-entropy lithium argyrodite sulfide solid electrolyte material, which has a chemical formula of Li 5.9 Al 0.05 Si 0.05 Ge 0.05 Mg 0.05 Zn 0.05 In 0.05 P 0.7 S 4.05 F 0.25 O 0.15 N 0.05 Cl 0.5 Br 0.5 I 0.5 , and the specific implementation process is as follows:

[0049] The raw materials Li2S, LiCl, LiBr, Lil, P2S5, AIN, SiS2, GeO2, MgF2, ZnO, InF3 were dried at 60 °C for 10 h in a vacuum oven, and then the mass of the raw materials was calculated according to the molar ratio of the chemical formula. After weighing, they were put into a agate mortar and ground for 10 min, then put into a zirconia ball mill jar, and a planetary high-energy ball mill was used at 600 rpm / min for 8 h, with a ball-to-material ratio of 20:1. Under the protection of inert atmosphere, 600 mg of the mixed material precursor after ball milling was weighed and put into a mold, and a 10 mm round sheet was pressed at a pressure of 300 MPa, then sealed in a quartz tube containing inert gas, and a muffle furnace was used for high temperature heat treatment at 500 °C for 6 h, with a heating rate of 5 °C / min, then cooled to room temperature at a cooling rate of 20 °C / min, and finally ground into powder under the protection of inert atmosphere, to obtain Li 5.9 Al 0.05 Si 0.05 Ge 0.05 Mg 0.05 Zn 0.05 In 0.05 P 0.7 S 4.05 F 0.25 O 0.15 N 0.05 Cl 0.5 Br 0.5 I 0.5 High-entropy lithium argyrodite sulfide electrolyte.

[0050] Figure 1 The SEM morphology of the high-entropy lithium argyrodite sulfide electrolyte prepared in Example 1 was observed, and it was found that the particle size was about 10 μm. Figure 2 The XRD pattern of the sulfide electrolyte in Example 1 was a typical argyrodite sulfide with a cubic crystal structure of F-43m space group. The electrochemical test contents of the argyrodite sulfide electrolyte in this example 1 are as follows:

[0051] 1) Testing of ionic conductivity and activation energy: Under inert gas protection, 200 mg of the sulfide electrolyte powder prepared in Example 1 was weighed and placed into a specially made solid-state battery mold. The mold was then pressurized at 300 MPa. Subsequently, variable-temperature AC impedance spectroscopy was performed using a high-power electrochemical analyzer. Based on the obtained impedance values ​​and the Arrhenius equation, the ionic conductivity and activation energy of the sulfide solid electrolyte in Example 1 were calculated. The calculation results are shown in Table 1. Simultaneously, the configurational entropy of the high-entropy lithium-silver-germanium sulfide solid electrolyte in Example 1 was calculated using thermodynamic formulas. The calculation results are shown in Table 1. It can be found that the configurational entropy of the sulfide electrolyte prepared in Example 1 is 1.54 R (>1.5 R), which conforms to the characteristics of high-entropy materials, and its ionic conductivity is as high as 11.2 mS / cm.

[0052] 2) Electrochemical performance testing: Under an inert atmosphere, 100 mg of the sulfide electrolyte powder prepared in Example 1 was weighed and placed into a specially made solid-state battery mold. The mold was then pressurized at 200 MPa to obtain a sulfide electrolyte sheet. LiCoO2 (LCO) positive electrode active material, the sulfide electrolyte from Example 1, and carbon nanofibers (VGCF) were weighed in a mass ratio of 70:30:1 and ground in an agate mortar for 30 min to ensure thorough mixing, forming a composite positive electrode material. 10 mg of the composite positive electrode material was weighed and evenly spread on one side of the sulfide electrolyte sheet. A 7 mm diameter lithium metal foil was placed on the other side of the sulfide electrolyte sheet. A pressure of 40 MPa was applied to the entire solid-state battery mold to ensure tight adhesion of all parts of the battery. The cycle performance of the battery was tested using a Blue Electric testing system, with a voltage range of 2.8 - 4.2 V (vs. Li / Li). + The charge / discharge rate is 0.5 C. The charge / discharge curve of the all-solid-state battery assembled based on Example 1 is as follows: Figure 4 As shown, after 1000 charge-discharge cycles, the capacity retention rate was 66.2%, and the discharge specific capacity was as high as 82.2 mAh / g, demonstrating good electrochemical stability of the entire battery.

[0053] 3) Air stability test: Under an inert atmosphere, 100 mg of the sulfide electrolyte powder prepared in Example 1 was weighed and tested using... A 10 mm mold was pressurized at 300 MPa and then demolded. The release of H2S was tested in a 5 L sealed container containing air with a humidity of 30%. Figure 5 After 2 hours of exposure, the H2S release from the sulfide electrolyte in Example 1 was 0.37 cm³. 3 / g.

[0054] Example 2

[0055] Embodiment 2 of the present application provides a preparation process of a high-entropy lithium argyrodite sulfide solid electrolyte material, which has a structural formula of Li 5.98 Al 0.04 Si 0.04 Ge 0.04 Ti 0.04 Mg 0.04 Zn 0.04 In 0.04 Cu 0.04 P 0.68 S 4.1 F 0.2 O 0.12 N 0.04 Se 0.0 4Cl 0.5 Br 0.5 I 0.5 The specific implementation process is as follows:

[0056] The raw materials Li2S, LiCl, LiBr, LiI, P2S5, AlN, SiS2, GeO2, TiCl4, MgF2, ZnO, InF3, and CuSe are subjected to 60 ℃ drying treatment in a vacuum oven for 10 h, and then the mass of the raw materials is calculated according to the molar ratio of the chemical formula, weighed, put into a maragda mortar for grinding for 10 min, then put into a zirconia ball mill jar, and a planetary high-energy ball mill is used for ball milling at 600 rpm / min for 8 h, with a ball-to-material ratio of 20:1. Under the protection of an inert atmosphere, 600 mg of the mixed material precursor after ball milling is weighed and put into a mold, and a 10 mm round sheet is pressed under a pressure of 300 MPa, then sealed in a quartz tube containing inert gas, and a muffle furnace is used for high-temperature heat treatment at 500 ℃ for 6 h, with a heating rate controlled at 5 ℃ / min, then cooled to room temperature at a cooling rate of 20 ℃ / min, and finally ground into powder under the protection of an inert atmosphere, to obtain Li 5.98 Al 0.04 Si 0.04 Ge 0.04 Ti 0.04 Mg 0.04 Zn 0.04 In 0.04 Cu 0.04 P 0.68 S 4.1 F 0.2 O 0.12 N 0.04 Se 0.04 Cl 0.5 Br 0.5 I 0.5High-entropy lithium argyrodite sulfide electrolyte. The performance test of Example 2 is consistent with Example 1, and the ionic conductivity and configuration entropy of the sulfide electrolyte prepared in Example 2 are calculated by formula as shown in Table 1, wherein the ionic conductivity can reach 11.5 mS / cm, and the configuration entropy AS config is 1.54 R (> 1.5 R), which belongs to a high-entropy electrolyte material.

[0057] Example 3

[0058] The present application Example 3 provides a preparation process of a high-entropy lithium argyrodite sulfide solid electrolyte material, and the structural formula is Li 6.06 Al 0.04 Si 0.04 Ge 0.04 Ti 0.04 Mn 0.04 Mg 0.04 Zn 0.04 In 0.04 Cu 0.04 Sn 0.04 P 0.6 S 4.02 F 0. 2O 0.16 N 0.04 Se 0.04 Te 0.04 Cl 0.5 Br 0.5 I 0.5 , and the specific implementation process is as follows:

[0059] The raw materials Li2S, LiCl, LiBr, LiI, P2S5, AlN, SiS2, GeO2, TiCl4, MnO2, MgF2, ZnTe, InF3, CuSe, SnCl4 are dried at 60 ℃ in a vacuum oven for 10 h, then the mass of the raw materials is calculated according to the molar ratio of the chemical formula, weighed and put into a maragda mortar for grinding for 10 min, then put into a zirconia ball mill jar, use a planetary high-energy ball mill at 600 rpm / min for 8 h, the ball-to-material ratio is 20:1. Under the protection of inert atmosphere, 600 mg of the mixed material precursor after ball milling is weighed and put into a mold, and a 10 mm round sheet is pressed under a pressure of 300 MPa, then sealed in a quartz tube containing inert gas, and a muffle furnace is used for high-temperature heat treatment at 500 ℃ for 6 h, the heating rate is controlled at 5 ℃ / min, then cooled to room temperature at a cooling rate of 20 ℃ / min, finally ground into powder under the protection of inert atmosphere, to obtain Li 6.06 Al 0.04 Si 0.04 Ge 0.04 Ti 0.04 Mn0.04 Mg 0.04 Zn 0.04 In 0.04 Cu 0.04 Sn 0.04 P 0.6 S 4.02 F 0.2 O 0.16 N 0.04 Se 0.04 Te 0.04 Cl 0.5 Br 0.5 I 0.5 High-entropy lithium argyrodite sulfide electrolyte. The performance test of Example 3 is consistent with Example 1, and the ionic conductivity and configurational entropy of the sulfide electrolyte prepared in Example 3 are calculated by formula as shown in Table 1, wherein the ionic conductivity can reach 12.6 mS / cm, and the configurational entropy ΔS config is 1.58 R (>1.5 R), which belongs to high-entropy electrolyte material.

[0060] Comparative Example 1-3

[0061] Comparative Example 1 (Li 5.5 PS 4.5 Cl 1.5 ), Comparative Example 2 (Li 5.5 PS 4.5 Cl 0.8 Br 0.7 ) and Comparative Example 3 (Li 5.5 PS 4.5 Cl 0.5 Br 0.5 I 0.5 ) sulfide solid electrolyte preparation process, except that the use of raw materials is different, other process conditions are consistent with Examples 1-3. The configurational entropy ΔS config , ionic conductivity σ and activation energy ΔE of the comparative examples are shown in Table 1, wherein the configurational entropy of the comparative examples is less than 1.5 R, which does not meet the basic characteristics of high-entropy materials, and belongs to low-entropy materials, and the ionic conductivity of the comparative examples is lower than that of the examples. Figures 6-10 respectively, the SEM morphology diagram, the XRD characteristic spectrum, the impedance spectrum, the charge-discharge cycle curve of the all-solid-state battery and the H2S release amount diagram of Comparative Example 1. By observing the SEM spectrum, it can be found that the particle size of the sulfide electrolyte of Comparative Example 1 is large (>10 μm). The XRD characteristic spectrum reflects that the sulfide electrolyte of Comparative Example 1 is a cubic crystal structure of argyrodite type. Figure 8 In the impedance spectrum, it can be found that the impedance value of the sulfide electrolyte of Comparative Example 1 at 25°C is 35.6 Ω, and its ionic conductivity is 5.2 mS / cm calculated by formula. Compared with Examples 1-3, the electrochemical performance is decreased.Figure 9 For the charge-discharge cycle curve of the all-solid-state battery assembled based on the comparative example, it can be found that after 300 cycles of charge-discharge cycle, the discharge specific capacity is sharply attenuated, only 39.1 mAh / g, which indicates that the electrochemical performance of the sulfide electrolyte in Comparative Example 1 is poor. The release amount of H2S of the sulfide electrolyte in Comparative Example 1 exposed to air with humidity of 30% for 2 h is 1.28 cm 3 / g, which is much higher than the release amount of H2S of the sulfide electrolyte in Example 1 under the same conditions.

[0062] Table 1. Configurational entropy ΔS, ionic conductivity and activation energy of sulfide electrolytes config

[0063]

[0064] In summary, the present application adopts the strategy of co-doping of cations and anions, and obtains a high-entropy lithium argyrodite-type sulfide solid electrolyte through a high-energy ball milling + high-temperature heat treatment process. Based on the hard-soft acid-base theory, the stability of the structure is improved by introducing soft acid cations, and the sensitivity of the electrolyte to water molecules in the air is reduced; the heterovalent doping of cations produces additional lithium vacancies in the structure, improving the ionic conductivity of the electrolyte; the introduction of inorganic anions generates a stable interfacial layer in situ at the lithium anode, preventing the contact between the electrolyte and the lithium anode and improving the stability of the anode interface; the introduction of halogen anions increases the degree of disorder of anions in the matrix, improves the configurational entropy of the material, and reduces the diffusion energy barrier of lithium ions, further improving the ionic conductivity of the electrolyte. Therefore, the ionic conductivity of the high-entropy lithium argyrodite-type sulfide solid electrolyte described in the present application can reach 10 mS cm −1 at room temperature, and the release amount of H2S when exposed to air with humidity of 30% is significantly reduced. At the same time, the high-entropy lithium argyrodite-type sulfide solid electrolyte of the present application can match the lithium cobalt oxide layered positive electrode material and the lithium metal / lithium alloy negative electrode material, and the full battery shows excellent charge-discharge performance. The high-entropy lithium argyrodite-type sulfide solid electrolyte of the present application has excellent ionic conductivity and excellent electrochemical stability, and its preparation process is simple and easy to control, and has the potential to become a commercial and industrialized sulfide solid electrolyte.​

Claims

1. A high-entropy lithium argyrodite sulfide solid electrolyte, characterized by, The chemical formula of the solid electrolyte material is: Li 5.9 Al 0.05 Si 0.05 Ge 0.05 Mg 0.05 Zn 0.05 In 0.05 P 0.7 S 4.05 F 0.25 O 0.15 N 0.05 Cl 0.5 Br 0.5 I 0.5 , or Li 5.98 Al 0.04 Si 0.04 Ge 0.04 Ti 0.04 Mg 0.04 Zn 0.04 In 0.04 Cu 0.04 P 0.68 S 4.1 F 0.2 O 0.12 N 0.04 Se 0.04 Cl 0.5 Br 0. 5I 0.5 , or Li 6.06 Al 0.04 Si 0.04 Ge 0.04 Ti 0.04 Mn 0.04 Mg 0.04 Zn 0.04 In 0.04 Cu 0.04 Sn 0.04 P 0.6 S 4.02 F 0.2 O 0.16 N 0.04 Se 0.0 4Te 0.04 Cl 0.5 Br 0.5 I 0.5 ; The preparation method of the high-entropy lithium argyrodite-type sulfide solid electrolyte comprises the following steps: Step 1) According to the target chemical formula, the required Li source compound, M source compound, N source compound, X source compound and Y source compound are subjected to drying treatment; wherein M is any two or more of Al, Si, Ge, Ti and Mn, N is any two or more of Mg, Zn, In, Cu, Sn, Bi and Sb, X is any two or more of F, O, N, Se and Te, and Y is any one or more of Cl, Br and I; Step 2) The raw materials after drying in step 1) are weighed and mixed according to the molar ratio of the electrolyte chemical formula under inert atmosphere protection to obtain a mixed material precursor; Step 3) The mixed material precursor obtained in step 2) is subjected to ball milling and tabletting process to obtain a tablet-shaped precursor; the mixed material precursor is subjected to tabletting treatment after ball milling in step 3), the pressure is 200-400 MPa, the diameter of the tablet-shaped precursor is 10 mm, and the mass is 500-1000 mg; Step 4) The tablet-shaped precursor obtained in step 3) is subjected to heat treatment, and after cooling to room temperature, it is ground into a powder under inert atmosphere protection to obtain a high-entropy sulfide solid electrolyte material; The high-temperature treatment process conditions of the tablet-shaped precursor in step 4) include a heat treatment temperature of 400-600 ℃, a heat treatment time of 6-8 h, and a heating rate of 1-5 ℃ / min; the cooling rate to room temperature is 10-20 ℃ / min.

2. The high-entropy lithium argyrodite sulfide solid electrolyte of claim 1, wherein, The drying treatment conditions in step 1) are vacuum drying at 60-80 ℃ for 10-12 h.

3. The high-entropy lithium argyrodite sulfide solid electrolyte of claim 1, wherein, In step 2), aagate mortar is used for mixing after weighing for 10-20 min.

4. The high-entropy lithium argyrodite sulfide solid electrolyte of claim 1, wherein, In step 3), the mixed material precursor is subjected to dry ball milling process, high-energy ball mill is used for mixing, the rotation speed of the ball mill is 400-600 rpm / min, the ball milling time is 8-12 h, the ball-to-material ratio is 20:1, and the mass ratio of large ball milling beads to small ball milling beads is 1:

1.

5. Use of a high-entropy lithium argyrodite sulfide solid electrolyte material, characterized in that The high-entropy lithium argyrodite-type sulfide solid electrolyte material of claim 1 is applied to a full solid-state lithium battery.

6. Use of a high-entropy lithium argyrodite sulfide solid electrolyte material, characterized in that The full solid-state lithium battery comprises a composite positive electrode layer, a sulfide electrolyte layer and a lithium negative electrode / composite negative electrode layer; The composite positive electrode layer and the sulfide electrolyte layer comprise the high-entropy lithium argyrodite-type sulfide solid electrolyte material of claim 1.

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