WO2024051220A1 - 一种高纯硫银锗矿相硫化物固体电解质及其制备方法 - Google Patents

一种高纯硫银锗矿相硫化物固体电解质及其制备方法 Download PDF

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WO2024051220A1
WO2024051220A1 PCT/CN2023/097287 CN2023097287W WO2024051220A1 WO 2024051220 A1 WO2024051220 A1 WO 2024051220A1 CN 2023097287 W CN2023097287 W CN 2023097287W WO 2024051220 A1 WO2024051220 A1 WO 2024051220A1
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sulfide
electrolyte
solid electrolyte
phase
lithium
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French (fr)
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姚霞银
刘高瞻
杨菁
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中国科学院宁波材料技术与工程研究所
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Priority to KR1020247003116A priority Critical patent/KR20240045209A/ko
Publication of WO2024051220A1 publication Critical patent/WO2024051220A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0065—Solid electrolytes
    • H01M2300/0068—Solid electrolytes inorganic
    • H01M2300/008—Halides
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention belongs to the field of battery technology and relates to a high-purity sulfide-silver-germanium mineral phase sulfide solid electrolyte and a preparation method thereof.
  • Solid electrolyte is an important component of all-solid-state batteries. Among them, sulfide-silver-germanium mineral phase sulfide solid electrolyte has high room temperature ionic conductivity and low electronic conductivity. It also has good mechanical properties, which is beneficial to electrodes in all-solid-state batteries. /Electrolyte forms a good solid-solid contact interface. However, most current sulfide-silver-germanium mineral phase solid electrolytes are impure and contain impurities such as raw materials or sintering intermediate products, which affect the chemical stability of the electrolyte and electrolyte/electrode interface reaction products.
  • high-purity sulfide-silver-germanium ore-phase sulfide solid electrolytes are usually produced by increasing the ball milling time of the precursor and extending the heat treatment time.
  • the preparation time is usually 1 to 2 weeks, and the resulting electrolyte has low room temperature ionic conductivity.
  • the rapid preparation of high-purity sulfide-silver-germanium ore-phase sulfide solid electrolyte and the improvement of room temperature ionic conductivity are crucial to the optimization of electrolyte and all-solid-state lithium battery performance.
  • the present invention provides a high-purity sulfide-silver-germanium mineral-phase sulfide solid electrolyte, which is a pure phase, and provides a method for preparing high-purity sulfide-silver germanium.
  • Mineral phase sulfide solid electrolyte method is provided.
  • One aspect of the present invention provides a high-purity silver-sulfide-germanium ore-phase sulfide solid electrolyte.
  • the molecular formula of the high-purity silver-sulfide-germanium ore-phase sulfide solid electrolyte is as shown in Formula I: Li 6 ⁇ i P 1-e E e S 5 ⁇ ig G g Cl 1 ⁇ i ⁇ t T tFormula I;
  • the high-purity sulfide-silver-germanium ore phase sulfide solid electrolyte is a pure phase with no raw material phase and no impurity peaks in its X-ray diffraction spectrum.
  • the crystal structure of the silver sulfide germanium phase is framed by PS 4 3- tetrahedrons, with Li + ions, halogen ions (Cl - , Br - , I - ) and some S 2- ions regularly dispersed therebetween.
  • the doped O preferentially replaces the S in the PS 4 3- tetrahedron, and part of the PS bonds become PO bonds.
  • the PO bond length is smaller than the PS bond length. Therefore, O doping will reduce the volume of the PS 4 3- group and cause changes in the crystal structure.
  • the present invention limits the number of G atoms to 0 ⁇ g ⁇ 0.5 and avoids excessive addition of O.
  • the halogen sites are also doped with Br - or I - ions with larger ion radius.
  • the room temperature ionic conductivity of the high-purity silver-sulfide-germanium ore-phase sulfide solid electrolyte is 3 ⁇ 10 -3 to 8 ⁇ 10 -2 S/cm.
  • Room temperature in this article refers to 15 to 35°C.
  • the high-purity silver sulfide germanium mineral phase sulfide solid electrolyte has excellent stability to lithium.
  • the high-purity silver-sulfide-germanium ore-phase sulfide solid electrolyte is exposed to a dew point of -40°C in a drying room for 4 hours, and the ionic conductivity decreases by ⁇ 15%.
  • the ionic conductivity decreases by ⁇ 20%.
  • the organic solvent is ethylene carbonate, fluoroethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, N-methylpyrrolidone, tetrahydrofuran, glycol dimethyl ether, anisole, 1,3-oxygen One or more of cyclopentane, toluene, xylene, chlorobenzene and n-heptane.
  • Another aspect of the present invention provides a high-purity silver sulfide germanium mineral phase sulfide solid battery
  • the preparation method of the solution includes the following steps:
  • the preparation method of lithium sulfide material includes one or more of ball milling method, carbothermal reduction method, lithiation of sulfur-containing chemical substances, lithium metal sulfide nanoparticles, and mutual reaction of lithium-containing and sulfur-containing substances.
  • the oxidizing agent in step b) is one or more of Li 2 O, P 2 O 5 , Li 3 PO 4 and I 2 . Adding an oxidant to the raw material will help the sulfide-silver-germanium ore phase sulfide solid electrolyte to obtain a high-purity phase based on the oxidation effect of the oxidant.
  • the mixing method in step b) includes one or more of manual grinding, mechanical stirring, mechanical shaking, mechanical ball milling, high-energy ball milling, and roller milling.
  • the ball-to-material ratio is (1 to 60): 1, the rotation speed is 200 to 600 rpm, and the time is 4 to 24 hours.
  • the annealing and sintering temperature in step c) is 400-600°C and the time is 1-48 hours.
  • Another aspect of the present invention provides an all-solid-state lithium secondary battery, including a positive electrode, a negative electrode and the high-purity silver sulfide germanium mineral phase sulfide solid electrolyte.
  • the present invention has the following beneficial effects:
  • the sulfide-silver-germanium mineral phase sulfide solid electrolyte provided by the present invention is a pure phase, and there is no impurity peak in its X-ray diffraction spectrum;
  • the high-purity sulfide-silver-germanium mineral phase sulfide solid electrolyte of the present invention has high ionic conductivity
  • the high-purity silver sulfide germanium ore phase sulfide solid electrolyte of the present invention has excellent stability to air, excellent stability to organic solvents, and excellent stability to lithium;
  • the present invention mixes and reacts raw materials including lithium sulfide materials and oxidants, Through the action of oxidant, the preparation of high-purity sulfide-silver-germanium ore phase sulfide solid electrolyte was achieved;
  • the high-purity sulfide-silver-germanium mineral phase sulfide solid electrolyte of the present invention is used in all-solid-state lithium batteries, which can effectively improve battery performance.
  • Figure 1 is the X-ray diffraction pattern of the Li 6 PS 4.8 O 0.2 Cl 0.5 Br 0.5 electrolyte of Example 1;
  • Figure 2 is a room temperature AC test impedance diagram of the Li 6 PS 4.8 O 0.2 Cl 0.5 Br 0.5 electrolyte of Example 1;
  • Figure 3 is a graph showing the stability of the Li 6 PS 4.8 O 0.2 Cl 0.5 Br 0.5 electrolyte to lithium in Example 1;
  • Figure 4 is the constant current charge and discharge curve of Li/Li 6 PS 4.8 O 0.2 Cl 0.5 Br 0.5 /NCM battery;
  • Figure 5 is the Li/Li 6 PS 4.8 O 0.2 Cl 0.5 Br 0.5 /NCM battery cycle diagram
  • Figure 6 is the X-ray diffraction pattern of the Li 6 PS 5 Cl 0.5 Br 0.5 electrolyte of Comparative Example 1;
  • Figure 7 is a room temperature AC test impedance diagram of the Li 6 PS 5 Cl 0.5 Br 0.5 electrolyte of Comparative Example 1;
  • Figure 8 is a graph showing the stability of Li 6 PS 5 Cl 0.5 Br 0.5 electrolyte to lithium in Comparative Example 1.
  • the molecular formula of the high-purity sulfide-silver-germanium mineral phase sulfide solid electrolyte in this embodiment is Li 6 PS 4.8 O 0.2 Cl 0.5 Br 0.5 , which is obtained by the following preparation method:
  • the electrolyte phase is a sulfide-silver-germanium mineral phase.
  • the electrolyte is a pure phase without raw material phases.
  • the X-ray diffraction pattern is shown in Figure 1. It can be seen that the electrolyte has no impurity peaks.
  • Li 6 PS 4.8 O 0.2 Cl 0.5 Br 0.5 electrolyte was soaked in anisole solvent, soaked at room temperature for 2 hours and then dried.
  • the impedance diagram of the AC test at room temperature after soaking is shown in Figure 2.
  • the electrolyte conductivity is shown in Table 1, which is 14.73. mS/cm.
  • the test results show that the Li/Li 6 PS 4.8 O 0.2 Cl 0.5 Br 0.5 /Li symmetrical battery can be cycled for 12,000 hours at a current density of 1mA/cm 2 without significant changes in the polarization voltage, indicating that the Li 6 PS 4.8 O 0.2 Cl 0.5 Br 0.5 electrolyte has excellent stability against lithium.
  • FIG. 4 is the constant current charge and discharge curve of Li/Li 6 PS 4.8 O 0.2 Cl 0.5 Br 0.5 /NCM battery
  • Figure 5 is the cycle chart of Li/Li 6 PS 4.8 O 0.2 Cl 0.5 Br 0.5 /NCM battery.
  • the battery was tested at 0.5C.
  • the discharge specific capacity in the first cycle was 3.31mAh/cm 2 and the Coulombic efficiency in the first cycle was 80.7%. After 50 cycles, the discharge specific capacity was 3.04mAh/cm 2 .
  • the molecular formula of the high-purity silver-sulfide germanium mineral phase sulfide solid electrolyte in this embodiment is Li 5.4 PS 4.3 O 0.1 Cl 1.4 I 0.2 , which is obtained by the following preparation method:
  • lithium sulfide material prepared by ball milling and the reaction of lithium-containing and sulfur-containing substances. Metal lithium and elemental sulfur are dissolved in tetrahydrofuran respectively. The ratio of the substances is 2.2:1. After ball milling and mixing for 24 hours at 200r/min Distill under reduced pressure and react to obtain Li 2 S;
  • the electrolyte phase is sulfide silver germanium mineral phase, and the electrolyte is a pure phase without raw material phase.
  • the original room temperature ionic conductivity of the Li 5.4 PS 4.3 O 0.1 Cl 1.4 I 0.2 electrolyte is 10.5mS/cm.
  • An all-solid-state primary lithium battery was assembled using lithium metal as the negative electrode and FeS 2 as the positive electrode for battery charge and discharge testing. Batteries are tested at 2mA /cm. After 500 cycles, the discharge specific capacity is 2.21mAh/cm 2 .
  • the molecular formula of the high-purity silver-sulfide germanium mineral phase sulfide solid electrolyte in this embodiment is Li 5.4 PS 4.2 O 0.2 Cl 1.1 Br 0.5 , which is obtained by the following preparation method:
  • the electrolyte phase is the sulfide silver germanium mineral phase, the electrolyte is a pure phase, and there is no raw material phase.
  • the original room temperature ionic conductivity of the Li 5.4 PS 4.2 O 0.2 Cl 0.5 Br 0.5 electrolyte is 19mS/cm.
  • the test current density of Li/Li 5.4 PS 4.2 O 0.2 Cl 0.5 Br 0.5 /Li symmetrical battery is 5mA/cm 2
  • the single charge and discharge time is 1 hour
  • the test capacity density is 5mAh/cm 2 .
  • the test results show that the Li/Li 5.4 PS 4.2 O 0.2 Cl 0.5 Br 0.5 /Li symmetrical battery can be cycled for 1000 cycles at a current density of 5mA/ cm2 without significant changes in the polarization voltage, indicating that the electrolyte has excellent stability against lithium.
  • An all-solid-state primary lithium battery was assembled using lithium boron alloy as the negative electrode and NCM as the positive electrode for battery charge and discharge testing. Batteries are tested at 5mA/ cm2 . After 1000 cycles, the discharge specific capacity is 5.71mAh/cm 2 .
  • the molecular formula of the high-purity silver-sulfide germanium mineral phase sulfide solid electrolyte in this embodiment is Li 6 PS 4.7 O 0.3 Cl 0.4 Br 0.4 I 0.2 , which is obtained by the following preparation method:
  • a) Preparation of lithium sulfide material Prepared by the lithium metal sulfide nanoparticle method. The metal lithium nanoparticles are dispersed in a tetrahydrofuran-n-hexane medium. A mixture of hydrogen sulfide gas and argon gas is passed inward. Li 2 is obtained after 24 hours of reaction. S;
  • the electrolyte phase is the sulfide silver germanium mineral phase, and the electrolyte is Pure phase, no raw material phase.
  • the original room temperature ionic conductivity of the Li 6 PS 4.7 O 0.3 Cl 0.4 Br 0.4 I 0.2 electrolyte is 25 mS/cm.
  • the obtained Li 6 PS 4.7 O 0.3 Cl 0.4 Br 0.4 I 0.2 electrolyte was soaked in fluoroethylene carbonate solvent, soaked at room temperature for 2 hours and then dried. After soaking, the room temperature ionic conductivity of the electrolyte was 20.25mS/cm.
  • An all-solid-state primary lithium battery was assembled using lithium indium alloy as the negative electrode and LFP as the positive electrode for battery charge and discharge testing. Batteries are tested at 15mA/ cm2 . After 1000 cycles, the discharge specific capacity is 16.3mAh/cm 2 .
  • the electrolyte molecular formula of Comparative Example 1 is Li 6 PS 5 Cl 0.5 Br 0.5 , which is obtained by the following preparation method:
  • lithium sulfide materials Prepared by the mutual reaction of lithium-containing and sulfur-containing substances. Metal lithium and elemental sulfur are dissolved in diethyl ether respectively. The ratio of the substances is 2.1:1. After mixing, distillation under reduced pressure, the reaction obtains Li 2 S;
  • the physical phase of the Li 6 PS 5 Cl 0.5 Br 0.5 electrolyte is a sulfide-silver germanium mineral phase, and there are impurity phases in the electrolyte.
  • the X-ray diffraction pattern is shown in Figure 6. It can be seen that the electrolyte has a Li 2 S impurity peak.
  • Li 6 PS 5 Cl 0.5 Br 0.5 electrolyte was soaked in anisole solvent, soaked at room temperature for 2 hours and then dried.
  • the impedance diagram of the room temperature AC test after soaking is shown in Figure 7.
  • the electrolyte conductivity is shown in Table 2, which is 3.75mS/ cm.
  • the test results show that the Li/Li 6 PS 5 Cl 0.5 Br 0.5 /Li symmetrical battery can be cycled for 1700 hours at a current density of 0.1mA/ cm2 , and the polarization voltage increases significantly, indicating that the electrolyte has poor stability to lithium.
  • the electrolyte molecular formula of Comparative Example 2 is Li 6 PS 4.4 O 0.6 Cl 0.5 Br 0.5 , which is obtained by the following Preparation method to obtain:
  • lithium sulfide materials Prepared by the mutual reaction of lithium-containing and sulfur-containing substances. Metal lithium and elemental sulfur are dissolved in diethyl ether respectively. The ratio of the substances is 2.1:1. After mixing, distillation under reduced pressure, the reaction obtains Li 2 S;
  • the physical phase of the Li 6 PS 4.4 O 0.6 Cl 0.5 Br 0.5 electrolyte is the sulfide silver germanium mineral phase, and there is a Li 2 S impurity phase in the electrolyte.
  • the room temperature ionic conductivity of the Li 6 PS 4.4 O 0.6 Cl 0.5 Br 0.5 electrolyte is 4.2 mS/cm.
  • Li 6 PS 4.4 O 0.6 Cl 0.5 Br 0.5 electrolyte was soaked in anisole solvent, soaked at room temperature for 2 hours and then dried. Its room temperature ionic conductivity was 3.07mS/cm.
  • the test current density of Li/Li 6 PS 4.4 O 0.6 Cl/Li symmetrical battery is 0.1mA/cm 2
  • the single charge and discharge time is 1 hour
  • the test capacity density is 0.1mAh/cm 2 .
  • the electrolyte molecular formula of Comparative Example 3 is Li 6 PSe 4.8 O 0.2 Cl 0.5 Br 0.5 , which is obtained by the following preparation method:
  • the physical phase of the Li 6 PSe 4.8 O 0.2 Cl 0.5 Br 0.5 electrolyte is the sulfide silver germanium mineral phase, and there is a Li 2 Se impurity phase in the electrolyte.
  • the room temperature ionic conductivity of the Li 6 PSe 4.8 O 0.2 Cl 0.5 Br 0.5 electrolyte is 1.7mS/cm.
  • Li 6 PSe 4.8 O 0.2 Cl 0.5 Br 0.5 electrolyte was soaked in anisole solvent, soaked at room temperature for 2 hours and then dried. Its room temperature ionic conductivity was 1.02mS/cm.
  • the test current density of Li/Li 6 PSe 4.8 O 0.2 Cl 0.5 Br 0.5 /Li symmetrical battery is 0.1mA/cm 2
  • the single charge and discharge time is 1 hour
  • the test capacity density is 0.1mAh/cm 2 .
  • the test results show that the Li/Li 6 PSe 4.8 O 0.2 Cl 0.5 Br 0.5 /Li symmetric battery can be cycled for 50 hours at a current density of 0.1mA/ cm2 , and the polarization voltage increases significantly, indicating that the electrolyte has poor stability to lithium.
  • the high-purity silver-sulfide germanium ore-phase sulfide solid electrolyte of Comparative Example 4 has a molecular formula of Li 6 PS 4.8 O 0.2 Cl, which is obtained by the following preparation method:
  • lithium sulfide materials Prepared by the mutual reaction of lithium-containing and sulfur-containing substances. Metal lithium and elemental sulfur are dissolved in diethyl ether respectively. The ratio of the substances is 2.1:1. After mixing, distillation under reduced pressure, the reaction obtains Li 2 S;
  • the Li 6 PS 4.8 O 0.2 Cl electrolyte phase is a sulfide-silver germanium mineral phase, and there is a Li 2 S impurity phase in the electrolyte.
  • the room temperature ionic conductivity of the Li 6 PS 4.8 O 0.2 Cl electrolyte is 9.8 mS/cm.
  • Li 6 PS 4.8 O 0.2 Cl electrolyte was soaked in anisole solvent, soaked at room temperature for 2 hours and then dried. Its room temperature ionic conductivity was 6.86mS/cm.
  • the test current density of Li/Li 6 PS 4.8 O 0.2 Cl/Li symmetrical battery is 0.1mA/cm 2
  • the single charge and discharge time is 1 hour
  • the test capacity density is 0.1mAh/cm 2 .
  • Test results show that the Li/Li 6 PS 4.8 O 0.2 Cl/Li symmetrical battery can be cycled for 1000 hours at a current density of 0.1mA/ cm2 , and the polarization voltage increases significantly, indicating that the electrolyte has poor stability to lithium.
  • the molecular formula of the high-purity sulfide-silver-germanium mineral phase sulfide solid electrolyte of Comparative Example 5 is Li 6 PS 4.8 O 0.2 Br, which is obtained by the following preparation method:
  • lithium sulfide materials Prepared by the mutual reaction of lithium-containing and sulfur-containing substances. Metal lithium and elemental sulfur are dissolved in diethyl ether respectively. The ratio of the substances is 2.1:1. After mixing, distillation under reduced pressure, the reaction obtains Li 2 S;
  • the physical phase of the Li 6 PS 4.8 O 0.2 Br electrolyte is the sulfide silver germanium mineral phase, and the Li 2 S impurity phase exists in the electrolyte.
  • the room temperature ionic conductivity of the Li 6 PS 4.8 O 0.2 Br electrolyte is 1.1 mS/cm.
  • Li 6 PS 4.8 O 0.2 Br electrolyte was soaked in anisole solvent, soaked at room temperature for 2 hours and then dried. Its room temperature ionic conductivity was 0.71mS/cm.
  • Li 6 PS 4.8 O 0.2 Br electrolyte was exposed to a drying room dew point of -40°C for 4 hours. After time, its room temperature ionic conductivity is 0.66mS/cm.
  • the test current density of Li/Li 6 PS 4.8 O 0.2 Br/Li symmetrical battery is 0.1mA/cm 2
  • the single charge and discharge time is 1 hour
  • the test capacity density is 0.1mAh/cm 2 .

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Abstract

本发明属于电池技术领域，涉及一种高纯硫银锗矿相硫化物固体电解质及其制备方法。所述高纯硫银锗矿相硫化物固体电解质的分子式如式I所示：Li6±iP1-eEeS5±i-gGgCl1±i±tTt式I；式I中，0≤i＜1，0≤e＜1，0＜g≤0.5，0.2≤t＜1，E为Ge、Si、Sn、Sb中的一种或多种，G为Se和O的复合物或O，T为Br和I中的一种或两种，所述高纯硫银锗矿相硫化物固体电解质为纯相。纯相电解质具有较高的离子电导率，且具有优异的对空气稳定性、优异的对有机溶剂稳定性，以及优异的对锂稳定性。

Description

一种高纯硫银锗矿相硫化物固体电解质及其制备方法 技术领域
本发明属于电池技术领域，涉及一种高纯硫银锗矿相硫化物固体电解质及其制备方法。
背景技术
固体电解质是全固态电池的重要部件，其中硫银锗矿相硫化物固体电解质具有较高的室温离子电导率和较低的电子电导率，同时具有良好的机械性能，有利于全固态电池中电极/电解质形成良好的固固接触界面。然而，目前多数硫银锗矿相硫化物固体电解质物相不纯，含有原料或烧结中间产物等杂相，影响电解质化学稳定性和电解质/电极界面反应产物。此外，高纯相的硫银锗矿相硫化物固体电解质通常通过提高前驱体球磨时长，延长热处理时间制得，制备时长通常在1到2周，且得到的电解质室温离子电导率较低。高纯硫银锗矿相硫化物固体电解质的快速制备及室温离子电导率提高对电解质及全固态锂电池性能的优化至关重要。
发明内容
本发明针对现有技术中硫银锗矿相硫化物固体电解质出现的不足，提供一种高纯硫银锗矿相硫化物固体电解质，其为纯相，以及提供一种制备高纯硫银锗矿相硫化物固体电解质方法。
本发明一个方面提供了一种高纯硫银锗矿相硫化物固体电解质，所述高纯硫银锗矿相硫化物固体电解质的分子式如式I所示：
Li6±iP1-eEeS5±i-gGgCl1±i±tTt  式I；
式I中，0≤i＜1，0≤e＜1，0＜g≤0.5，0.2≤t＜1，E为Ge、Si、Sn、Sb中的一种或多种，G为Se和O的复合物或O，T为Br和I中的一种或两种；
所述高纯硫银锗矿相硫化物固体电解质为纯相，没有原料物相，其X射线衍射谱图中无杂质峰。
硫银锗矿相晶体结构由PS4 3-四面体搭起框架，Li+离子，卤素离子(Cl-、Br-、I-)及部分S2-离子有规律的分散其间。掺杂的O优先取代PS4 3-四面体中的S，部分P-S键变为P-O键。但P-O键键长小于P-S键键长，因此，O掺杂会使PS4 3-基团的体积缩小，引起晶体结构变化。当Li6PS5Cl中O掺杂量过大时，PS4 3-基团体积收缩严重，晶体框架缩水，游离其间的Li+离子、S2-离子和Cl-离子容易被挤出，形成Li2S，LiCl等组分的杂相。因此，本发明为了避免杂相生成，将G的原子数限定为0＜g≤0.5，避免O添加量过多。同时为了保证O掺杂后晶体结构保持原有体积，卤素位也对应掺杂离子半径较大的Br-或I-离子，保证O掺杂量较大的情况下，尺寸较大的卤素离子可以弥补O掺杂带来的体积缩小，达到支撑框架的目的，避免游离其间的Li+离子、S2-离子和卤素离子被挤出形成杂相。
作为优选，所述高纯硫银锗矿相硫化物固体电解质的室温离子电导率为3×10-3～8×10-2S/cm。本文中的室温指的是15～35℃。
作为优选，所述高纯硫银锗矿相硫化物固体电解质具有优异的对锂稳定性。
作为优选，所述高纯硫银锗矿相硫化物固体电解质在干燥房露点-40℃中暴露4小时，离子电导率下降≤15％。
作为优选，所述高纯硫银锗矿相硫化物固体电解质在室温下于有机溶剂中浸泡2小时，离子电导率下降≤20％。
作为优选，有机溶剂为碳酸乙烯酯、氟代碳酸乙烯酯、碳酸甲乙酯、碳酸二甲酯、N-甲基吡咯烷酮、四氢呋喃、乙二醇二甲醚、苯甲醚、1,3-氧环戊烷、甲苯、二甲苯、氯苯、正庚烷中的一种或几种。
本发明另一个方面提供了一种高纯硫银锗矿相硫化物固体电 解质的制备方法，包括以下步骤：
a)、制备硫化锂材料；
b)、将包括硫化锂材料和氧化剂在内的原料按摩尔比称取并混合得到电解质前驱体；
c)、将步骤b)得到的前驱体退火烧结，得到高纯硫银锗矿相硫化物固体电解质。
作为优选，硫化锂材料的制备方法包括球磨法、碳热还原法、锂化含硫化学物质、硫化金属锂纳米颗粒、含锂和含硫物质互相反应中的一种或几种。
作为优选，步骤b)中的氧化剂为Li2O、P2O5、Li3PO4、I2中的一种或几种。原料中加入氧化剂，基于氧化剂的氧化作用，有利于硫银锗矿相硫化物固体电解质获得高纯相。
作为优选，步骤b)中的混合方法包括手动研磨、机械搅拌、机械震荡、机械球磨、高能球磨、辊磨中的一种或几种。
当步骤b)中的混合方式为高能球磨或辊磨时，球料比为(1～60)：1，转速为200～600rpm，时间为4～24小时。
作为优选，步骤c)中的退火烧结温度为400～600℃，时间为1～48小时。
本发明另一个方面提供了一种全固态锂二次电池，包括正极、负极和所述高纯硫银锗矿相硫化物固体电解质。
与现有技术相比，本发明具有以下有益效果：
1、本发明提供的硫银锗矿相硫化物固体电解质为纯相，其X射线衍射谱图中无杂质峰；
2、本发明的高纯硫银锗矿相硫化物固体电解质具有较高的离子电导率；
3、本发明的高纯硫银锗矿相硫化物固体电解质具有优异的对空气稳定性、优异的对有机溶剂稳定性，以及优异的对锂稳定性；
4、本发明将包括硫化锂材料和氧化剂在内的原料混合反应， 通过氧化剂的作用，实现了高纯度硫银锗矿相硫化物固体电解质的制备；
5、本发明的高纯硫银锗矿相硫化物固体电解质应用于全固态锂电池中，可以有效提高电池性能。
附图说明
图1为实施例1的Li6PS4.8O0.2Cl0.5Br0.5电解质的X射线衍射图谱；
图2为实施例1的Li6PS4.8O0.2Cl0.5Br0.5电解质的室温交流测试阻抗图；
图3为实施例1的Li6PS4.8O0.2Cl0.5Br0.5电解质对锂稳定性图；
图4为Li/Li6PS4.8O0.2Cl0.5Br0.5/NCM电池的恒流充放电曲线图；
图5为Li/Li6PS4.8O0.2Cl0.5Br0.5/NCM电池循环图；
图6为对比例1的Li6PS5Cl0.5Br0.5电解质的X射线衍射图谱；
图7为对比例1的Li6PS5Cl0.5Br0.5电解质的室温交流测试阻抗图；
图8为对比例1的Li6PS5Cl0.5Br0.5电解质对锂稳定性图。
具体实施方式
下面通过具体实施例和附图，对本发明的技术方案作进一步描述说明，应当理解的是，此处所描述的具体实施例仅用于帮助理解本发明，不用于本发明的具体限制。如果无特殊说明，本发明的实施例中所采用的原料均为本领域常用的原料，实施例中所采用的方法，均为本领域的常规方法。
实施例1
本实施例的高纯硫银锗矿相硫化物固体电解质分子式为Li6PS4.8O0.2Cl0.5Br0.5，其通过以下制备方法获得：
a)、制备硫化锂材料：通过含锂和含硫物质互相反应制备，金属锂和单质硫分别溶解于乙醚，物质的量比例为2.1：1，混合 后减压蒸馏，反应得到Li2S；
b)、将Li2S、P2S5、P2O5、LiCl、LiBr按摩尔比称量倒入玛瑙研钵中，手磨30分钟后得到电解质前驱体；
c)、将电解质前驱体在真空下550℃烧结4小时，得到Li6PS4.8O0.2Cl0.5Br0.5电解质。
Li6PS4.8O0.2Cl0.5Br0.5电解质物相为硫银锗矿相，电解质为纯相，无原料物相，其X射线衍射图谱见图1，可以看出电解质无杂质峰。
Li6PS4.8O0.2Cl0.5Br0.5电解质的原始室温交流测试阻抗图见图2，其室温离子电导率见表1，为16mS/cm。
将所得Li6PS4.8O0.2Cl0.5Br0.5电解质浸泡于苯甲醚溶剂中，室温下浸泡2小时后干燥，浸泡后室温交流测试阻抗图见图2，其电解质电导率见表1，为14.73mS/cm。
将所得Li6PS4.8O0.2Cl0.5Br0.5电解质在干燥房露点-40℃中暴露4小时后，室温交流测试阻抗图见图2，其室温离子电导率见表1，为14.56mS/cm。
表1 Li6PS4.8O0.2Cl0.5Br0.5电解质室温离子电导率
为了进一步研究制备的Li6PS4.8O0.2Cl0.5Br0.5电解质材料对锂金属电极的稳定性，以考察使用锂金属电极作为负极的可行性，将电解质与金属锂组装对称电池进行恒流充放电测试，测试结果见图3。Li/Li6PS4.8O0.2Cl0.5Br0.5/Li对称电池测试电流密度为1mA/cm2，单次充放电时长为1小时，测试容量密度为1mAh/cm2。 测试结果表明，Li/Li6PS4.8O0.2Cl0.5Br0.5/Li对称电池在1mA/cm2电流密度下可循环12000小时，极化电压没有明显变化，表明Li6PS4.8O0.2Cl0.5Br0.5电解质具有优异的对锂稳定性。
以金属锂为负极，LiNi0.8Co0.1Mn0.1O2(NCM)为正极组装全固态原锂电池进行电池充放电测试。图4为Li/Li6PS4.8O0.2Cl0.5Br0.5/NCM电池的恒流充放电曲线图，图5为Li/Li6PS4.8O0.2Cl0.5Br0.5/NCM电池循环图。电池在0.5C下进行测试，首圈放电比容量3.31mAh/cm2，首圈库伦效率为80.7％。循环50圈后，放电比容量为3.04mAh/cm2。
实施例2
本实施例的高纯硫银锗矿相硫化物固体电解质分子式为Li5.4PS4.3O0.1Cl1.4I0.2，其通过以下制备方法获得：
a)、制备硫化锂材料：通过球磨法及含锂和含硫物质互相反应制备，金属锂和单质硫分别溶解于四氢呋喃，物质的量比例为2.2：1，200r/min下球磨混合24小时后减压蒸馏，反应得到Li2S；
b)、将Li2S、Li3PO4、LiCl、I2按摩尔比称量倒入搅拌罐进行机械搅拌，300r/min下搅拌1小时，完成后倒入高能球磨罐中进行高能球磨，球料比为30:1，转速300rpm，高能球磨24小时得到电解质前驱体；
c)、将电解质前驱体在真空下540℃烧结12小时，得到Li5.4PS4.3O0.1Cl1.4I0.2电解质。
Li5.4PS4.3O0.1Cl1.4I0.2电解质物相为硫银锗矿相，电解质为纯相，无原料物相。
Li5.4PS4.3O0.1Cl1.4I0.2电解质的原始室温离子电导率为10.5mS/cm。
将所得Li5.4PS4.3O0.1Cl1.4I0.2电解质浸泡于苯甲醚+四氢呋喃溶剂中(苯甲醚：四氢呋喃体积比为1:2)，室温下浸泡2小时后干燥，浸泡后电解质的室温离子电导率为9.03mS/cm。
将所得Li5.4PS4.3O0.1Cl1.4I0.2电解质置于干燥房露点-40℃中暴露4h后，其室温离子电导率为9.77mS/cm。
为了进一步研究制备的Li5.4PS4.3O0.1Cl1.4I0.2电解质材料对锂金属电极的稳定性，以考察使用锂金属电极作为负极的可行性，将电解质与金属锂组装对称电池进行恒流充放电测试。Li/Li5.4PS4.3O0.1Cl1.4I0.2/Li对称电池测试电流密度为2mA/cm2，单次充放电时长为1小时，测试容量密度为2mAh/cm2。测试结果表明，Li/Li5.4PS4.3O0.1Cl1.4I0.2/Li对称电池在2mA/cm2电流密度下可循环500周，极化电压没有明显变化，表明电解质具有优异的对锂稳定性。
以锂金属为负极，FeS2为正极组装全固态原锂电池进行电池充放电测试。电池在2mA/cm2下进行测试。循环500圈后，放电比容量为2.21mAh/cm2。
实施例3
本实施例的高纯硫银锗矿相硫化物固体电解质分子式为Li5.4PS4.2O0.2Cl1.1Br0.5，其通过以下制备方法获得：
a)、制备硫化锂材料：将干燥的硫粉与氢化锂粉按物质的量比1：1混合，加入球磨罐中，室温下100r/min条件下球磨24小时，得到Li2S；
b)、将Li2S、P2O5、LiCl、LiBr按摩尔比称量倒入搅拌罐进行机械搅拌，400r/min下搅拌8小时得到电解质前驱体；
c)、将电解质前驱体在真空下580℃烧结24小时，得到Li5.4PS4.2O0.2Cl0.5Br0.5电解质。
Li5.4PS4.2O0.2Cl0.5Br0.5电解质物相为硫银锗矿相，电解质为纯相，无原料物相。
Li5.4PS4.2O0.2Cl0.5Br0.5电解质的原始室温离子电导率为19mS/cm。
将所得Li5.4PS4.2O0.2Cl0.5Br0.5电解质浸泡于碳酸二甲酯+氟代 碳酸乙烯酯溶剂中(碳酸二甲酯：氟代碳酸乙烯酯体积比为4:1)，室温下浸泡2小时后干燥，浸泡后电解质室温离子电导率为16.72mS/cm。
将所得Li5.4PS4.2O0.2Cl0.5Br0.5电解质置于干燥房露点-40℃中暴露4h后，其室温离子电导率为17.37mS/cm。
为了进一步研究制备的Li5.4PS4.2O0.2Cl0.5Br0.5电解质材料对锂金属电极的稳定性，以考察使用锂金属电极作为负极的可行性，将电解质与金属锂组装对称电池进行恒流充放电测试。Li/Li5.4PS4.2O0.2Cl0.5Br0.5/Li对称电池测试电流密度为5mA/cm2，单次充放电时长为1小时，测试容量密度为5mAh/cm2。测试结果表明，Li/Li5.4PS4.2O0.2Cl0.5Br0.5/Li对称电池在5mA/cm2电流密度下可循环1000周，极化电压没有明显变化，表明电解质具有优异的对锂稳定性。
以锂硼合金为负极，NCM为正极组装全固态原锂电池进行电池充放电测试。电池在5mA/cm2下进行测试。循环1000圈后，放电比容量为5.71mAh/cm2。
实施例4
本实施例的高纯硫银锗矿相硫化物固体电解质分子式为Li6PS4.7O0.3Cl0.4Br0.4I0.2，其通过以下制备方法获得：
a)、制备硫化锂材料：通过硫化金属锂纳米颗粒法制备，金属锂纳米颗粒分散在四氢呋喃-正己烷介质中，向内通硫化氢气体和氩气混合气，反应24小时后制得Li2S；
b)、将Li2S、P2O5、LiCl、LiBr、LiI按摩尔比称量倒入研钵进行研磨，完成后倒入辊磨罐中进行辊磨，球料比为5:1，转速200rpm，辊磨24小时得到电解质前驱体；
c)、将电解质前驱体在真空下420℃烧结48小时，得到Li6PS4.7O0.3Cl0.4Br0.4I0.2电解质。
Li6PS4.7O0.3Cl0.4Br0.4I0.2电解质物相为硫银锗矿相，电解质为 纯相，无原料物相。
Li6PS4.7O0.3Cl0.4Br0.4I0.2电解质的原始室温离子电导率为25mS/cm。
将所得Li6PS4.7O0.3Cl0.4Br0.4I0.2电解质浸泡于氟代碳酸乙烯酯溶剂中，室温下浸泡2小时后干燥，浸泡后电解质室温离子电导率为20.25mS/cm。
将所得Li6PS4.7O0.3Cl0.4Br0.4I0.2置于干燥房露点-40℃中暴露4h后，其室温离子电导率为24mS/cm。
为了进一步研究制备的Li6PS4.7O0.3Cl0.4Br0.4I0.2电解质材料对锂金属电极的稳定性，以考察使用锂金属电极作为负极的可行性，将电解质与金属锂组装对称电池进行恒流充放电测试。Li/Li6PS4.7O0.3Cl0.4Br0.4I0.2/Li对称电池测试电流密度为15mA/cm2，单次充放电时长为1小时，测试容量密度为15mAh/cm2。测试结果表明，Li/Li6PS4.7O0.3Cl0.4Br0.4I0.2/Li对称电池在15mA/cm2电流密度下可循环1000周，极化电压没有明显变化，表明电解质具有优异的对锂稳定性。
以锂铟合金为负极，LFP为正极组装全固态原锂电池进行电池充放电测试。电池在15mA/cm2下进行测试。循环1000圈后，放电比容量为16.3mAh/cm2。
对比例1
对比例1电解质分子式为Li6PS5Cl0.5Br0.5，其通过以下制备方法获得：
a)、制备硫化锂材料：通过含锂和含硫物质互相反应制备，金属锂和单质硫分别溶解于乙醚，物质的量比例为2.1：1，混合后减压蒸馏，反应得到Li2S；
b)、将Li2S、P2S5、LiCl、LiBr按摩尔比称量倒入玛瑙研钵中，手磨30分钟后得到电解质前驱体；
c)、将电解质前驱体在真空下550℃烧结4小时，得到 Li6PS5Cl0.5Br0.5电解质。
Li6PS5Cl0.5Br0.5电解质物相为硫银锗矿相，电解质存在杂相，其X射线衍射图谱见图6，可以看出电解质有Li2S杂质峰。
Li6PS5Cl0.5Br0.5电解质的原始室温交流测试阻抗图见图7，其室温离子电导率见表2，为5mS/cm。
将所得Li6PS5Cl0.5Br0.5电解质浸泡于苯甲醚溶剂中，室温下浸泡2小时后干燥，浸泡后室温交流测试阻抗图见图7，其电解质电导率见表2，为3.75mS/cm。
将所得Li6PS5Cl0.5Br0.5电解质在干燥房露点-40℃中暴露4小时后，室温交流测试阻抗图见图7，其室温离子电导率见表2，为3.5mS/cm。
表2 Li6PS5Cl0.5Br0.5电解质室温离子电导率
为了进一步研究制备的Li6PS5Cl0.5Br0.5电解质材料对锂金属电极的稳定性，以考察使用锂金属电极作为负极的可行性，将电解质与金属锂组装对称电池进行恒流充放电测试，测试结果见图8。Li/Li6PS5Cl0.5Br0.5/Li对称电池测试电流密度为0.1mA/cm2，单次充放电时长为1小时，测试容量密度为0.1mAh/cm2。测试结果表明，Li/Li6PS5Cl0.5Br0.5/Li对称电池在0.1mA/cm2电流密度下可循环1700小时，极化电压明显增大，表明电解质对锂稳定性较差。
对比例2
对比例2电解质分子式为Li6PS4.4O0.6Cl0.5Br0.5，其通过以下 制备方法获得：
a)、制备硫化锂材料：通过含锂和含硫物质互相反应制备，金属锂和单质硫分别溶解于乙醚，物质的量比例为2.1：1，混合后减压蒸馏，反应得到Li2S；
b)、将Li2S、P2S5、P2O5、LiCl按摩尔比称量倒入玛瑙研钵中，手磨30分钟后得到电解质前驱体；
c)、将电解质前驱体在真空下550℃烧结4小时，得到Li6PS4.4O0.6Cl0.5Br0.5电解质。
Li6PS4.4O0.6Cl0.5Br0.5电解质物相为硫银锗矿相，电解质存在Li2S杂相。
Li6PS4.4O0.6Cl0.5Br0.5电解质的室温离子电导率为4.2mS/cm。
将所得Li6PS4.4O0.6Cl0.5Br0.5电解质浸泡于苯甲醚溶剂中，室温下浸泡2小时后干燥，其室温离子电导率为3.07mS/cm。
将所得Li6PS4.4O0.6Cl0.5Br0.5电解质在干燥房露点-40℃中暴露4小时后，其室温离子电导率为2.90mS/cm。
为了进一步研究制备的Li6PS4.4O0.6Cl0.5Br0.5电解质材料对锂金属电极的稳定性，以考察使用锂金属电极作为负极的可行性，将电解质与金属锂组装对称电池进行恒流充放电测试。Li/Li6PS4.4O0.6Cl/Li对称电池测试电流密度为0.1mA/cm2，单次充放电时长为1小时，测试容量密度为0.1mAh/cm2。测试结果表明，Li/Li6PS4.4O0.6Cl/Li对称电池在0.1mA/cm2电流密度下可循环950小时，极化电压明显增大，表明电解质对锂稳定性较差。
对比例3
对比例3电解质分子式为Li6PSe4.8O0.2Cl0.5Br0.5，其通过以下制备方法获得：
a)、将Li2Se、P2Se5、P2O5、LiCl、LiBr按摩尔比称量倒入玛瑙研钵中，手磨30分钟后得到电解质前驱体；
b)、将电解质前驱体在真空下550℃烧结4小时，得到 Li6PSe4.8O0.2Cl0.5Br0.5电解质。
Li6PSe4.8O0.2Cl0.5Br0.5电解质物相为硫银锗矿相，电解质存在Li2Se杂相。
Li6PSe4.8O0.2Cl0.5Br0.5电解质的室温离子电导率为1.7mS/cm。
将所得Li6PSe4.8O0.2Cl0.5Br0.5电解质浸泡于苯甲醚溶剂中，室温下浸泡2小时后干燥，其室温离子电导率为1.02mS/cm。
将所得Li6PSe4.8O0.2Cl0.5Br0.5电解质在干燥房露点-40℃中暴露4小时后，其室温离子电导率为0.85mS/cm。
为了进一步研究制备的Li6PSe4.8O0.2Cl0.5Br0.5电解质材料对锂金属电极的稳定性，以考察使用锂金属电极作为负极的可行性，将电解质与金属锂组装对称电池进行恒流充放电测试。Li/Li6PSe4.8O0.2Cl0.5Br0.5/Li对称电池测试电流密度为0.1mA/cm2，单次充放电时长为1小时，测试容量密度为0.1mAh/cm2。测试结果表明，Li/Li6PSe4.8O0.2Cl0.5Br0.5/Li对称电池在0.1mA/cm2电流密度下可循环50小时，极化电压明显增大，表明电解质对锂稳定性较差。
对比例4
对比例4的高纯硫银锗矿相硫化物固体电解质分子式为Li6PS4.8O0.2Cl，其通过以下制备方法获得：
a)、制备硫化锂材料：通过含锂和含硫物质互相反应制备，金属锂和单质硫分别溶解于乙醚，物质的量比例为2.1：1，混合后减压蒸馏，反应得到Li2S；
b)、将Li2S、P2S5、P2O5、LiCl按摩尔比称量倒入玛瑙研钵中，手磨30分钟后得到电解质前驱体；
c)、将电解质前驱体在真空下550℃烧结4小时，得到Li6PS4.8O0.2Cl电解质。
Li6PS4.8O0.2Cl电解质物相为硫银锗矿相，电解质存在Li2S杂相。
Li6PS4.8O0.2Cl电解质的室温离子电导率为9.8mS/cm。
将所得Li6PS4.8O0.2Cl电解质浸泡于苯甲醚溶剂中，室温下浸泡2小时后干燥，其室温离子电导率为6.86mS/cm。
将所得Li6PS4.8O0.2Cl电解质在干燥房露点-40℃中暴露4小时后，其室温离子电导率为6.57mS/cm。
为了进一步研究制备的Li6PS4.8O0.2Cl电解质材料对锂金属电极的稳定性，以考察使用锂金属电极作为负极的可行性，将电解质与金属锂组装对称电池进行恒流充放电测试。Li/Li6PS4.8O0.2Cl/Li对称电池测试电流密度为0.1mA/cm2，单次充放电时长为1小时，测试容量密度为0.1mAh/cm2。测试结果表明，Li/Li6PS4.8O0.2Cl/Li对称电池在0.1mA/cm2电流密度下可循环1000小时，极化电压明显增大，表明电解质对锂稳定性较差。
对比例5
对比例5的高纯硫银锗矿相硫化物固体电解质分子式为Li6PS4.8O0.2Br，其通过以下制备方法获得：
a)、制备硫化锂材料：通过含锂和含硫物质互相反应制备，金属锂和单质硫分别溶解于乙醚，物质的量比例为2.1：1，混合后减压蒸馏，反应得到Li2S；
b)、将Li2S、P2S5、P2O5、LiCl按摩尔比称量倒入玛瑙研钵中，手磨30分钟后得到电解质前驱体；
c)、将电解质前驱体在真空下550℃烧结4小时，得到Li6PS4.8O0.2Br电解质。
Li6PS4.8O0.2Br电解质物相为硫银锗矿相，电解质存在Li2S杂相。
Li6PS4.8O0.2Br电解质的室温离子电导率为1.1mS/cm。
将所得Li6PS4.8O0.2Br电解质浸泡于苯甲醚溶剂中，室温下浸泡2小时后干燥，其室温离子电导率为0.71mS/cm。
将所得Li6PS4.8O0.2Br电解质在干燥房露点-40℃中暴露4小 时后，其室温离子电导率为0.66mS/cm。
为了进一步研究制备的Li6PS4.8O0.2Br电解质材料对锂金属电极的稳定性，以考察使用锂金属电极作为负极的可行性，将电解质与金属锂组装对称电池进行恒流充放电测试。Li/Li6PS4.8O0.2Br/Li对称电池测试电流密度为0.1mA/cm2，单次充放电时长为1小时，测试容量密度为0.1mAh/cm2。测试结果表明，Li/Li6PS4.8O0.2Br/Li对称电池在0.1mA/cm2电流密度下可循环100小时，极化电压明显增大，表明电解质对锂稳定性较差
最后应说明的是，本文中所描述的具体实施例仅仅是对本发明精神作举例说明，而并非对本发明的实施方式的限定。本发明所属技术领域的技术人员可以对所描述的具有实施例做各种各样的修改或补充或采用类似的方式替代，这里无需也无法对所有的实施方式予以全例。而这些属于本发明的实质精神所引申出的显而易见的变化或变动仍属于本发明的保护范围，把它们解释成任何一种附加的限制都是与本发明精神相违背的。

Claims (12)

  1. 一种高纯硫银锗矿相硫化物固体电解质，其特征在于，所述高纯硫银锗矿相硫化物固体电解质的分子式如式I所示：
    Li6±iP1-eEeS5±i-gGgCl1±i±tTt    式I；
    式I中，0≤i＜1，0≤e＜1，0＜g≤0.5，0.2≤t＜1，E为Ge、Si、Sn、Sb中的一种或多种，G为Se和O的复合物或O，T为Br和I中的一种或两种；
    所述高纯硫银锗矿相硫化物固体电解质为纯相。
  2. 根据权利要求1所述的高纯硫银锗矿相硫化物固体电解质，其特征在于，所述高纯硫银锗矿相硫化物固体电解质的室温离子电导率为1×10-3～8×10-2S/cm。
  3. 根据权利要求1所述的高纯硫银锗矿相硫化物固体电解质，其特征在于，所述高纯硫银锗矿相硫化物固体电解质在干燥房露点-40℃中暴露4小时，离子电导率下降≤15％。
  4. 根据权利要求1所述的高纯硫银锗矿相硫化物固体电解质，其特征在于，所述高纯硫银锗矿相硫化物固体电解质在室温下于有机溶剂中浸泡2小时，离子电导率下降≤20％。
  5. 根据权利要求4所述的高纯硫银锗矿相硫化物固体电解质，其特征在于，有机溶剂为碳酸乙烯酯、氟代碳酸乙烯酯、碳酸甲乙酯、碳酸二甲酯、N-甲基吡咯烷酮、四氢呋喃、乙二醇二甲醚、苯甲醚、1,3-氧环戊烷、甲苯、二甲苯、氯苯、正庚烷中的一种或几种。
  6. 一种如权利要求1所述的高纯硫银锗矿相硫化物固体电解质的制备方法，其特征在于，包括以下步骤：
    a)、制备硫化锂材料；
    b)、将包括硫化锂材料和氧化剂在内的原料按摩尔比称取并混合；
    c)、将步骤b)得到的粉末退火烧结，得到高纯硫银锗矿相硫化物固体电解质。
  7. 根据权利要求6所述的制备方法，其特征在于，硫化锂材料的制备方法包括球磨法、碳热还原法、锂化含硫化学物质、硫化金属锂纳米颗粒、含锂和含硫物质互相反应中的一种或几种。
  8. 根据权利要求6所述的制备方法，其特征在于，所述氧化剂为Li2O、P2O5、Li3PO4、I2中的一种或几种。
  9. 根据权利要求6所述的制备方法，其特征在于，步骤b)中的混合方法包括手动研磨、机械搅拌、机械震荡、机械球磨、高能球磨、辊磨中的一种或几种。
  10. 根据权利要求9所述的制备方法，其特征在于，步骤b)中的混合方式为高能球磨或辊磨时，球料比为(1～60)：1，转速为200～600rpm，时间为4～24小时。
  11. 根据权利要求6所述的制备方法，其特征在于，步骤c)中的退火烧结温度为400～600℃，时间为1～48小时。
  12. 一种全固态锂二次电池，其特征在于，包括正极、负极和权利要求1所述的高纯硫银锗矿相硫化物固体电解质。
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