在无机固体电解质中，硫化物固体电解质有许多优点，例如室温锂离子电导率高，电化学窗口宽（>5.0 V vs. Li+/Li），对金属锂有良好的稳定性。因此硫化物固体电解质在新一代锂电池中有极好的应用前景。但是这类材料距离实际应用还有一些问题需要解决：1）原料Li2S要求纯度高、制备工艺复杂、价格昂贵；2）三元硫化物固体电解质合成工艺有待优化；3）三元硫化物固体电解质的电化学稳定性需要进一步提高。针对上述问题，本论文从优化硫化物固体电解质材料的合成工艺及掺杂改性研究入手，在保持较高锂离子电导率的条件下，寻找改善三元硫化物固体电解质的电化学稳定性的方法。主要研究内容如下：（1）高能球磨法制备高纯度Li2S。金属锂与升华硫作为原材料在充Ar手套箱（H2O<1 ppm，O2<1 ppm）中高能球磨制备Li2S，最佳球磨时间为180 min，最佳原料配比为Li=0.42 g，S=1.00 g。本方法制备的Li2S粉末纯度高，所得XRD衍射峰与标准峰一致。（2）优化合成三元硫化物固体电解质Li10GeP2S12（LGPS）。原材料以Li﹕Ge﹕P﹕S=10﹕1﹕2﹕24的摩尔比（由于升华，硫需过量），在充Ar手套箱（H2O<1 ppm，O2<1 ppm）中混合称重，经高能球磨及二段烧结工艺，合成具有thio-LISICON结构的Li10GeP2S12。该方法制备的LGPS具有规则的晶体结构，室温电导率σLi为3.27×10-3 S·cm-1，活化能为25.5 kJ·mol-1，电化学电压窗口高于6.0 V（vs. Li+/Li）。LiCoO2在全固态电池Li/LGPS/LiCoO2中的首次放电容量为119.6 mAh·g-1（20圈循环后容量保持率为89.6%）。该方法成本低、效率高、工艺简单，可以很好地替代传统方法，该方法合成的LGPS在以锂为负极的固态电池中具有广阔的应用前景。（3）对三元硫化物固体电解质Li10GeP2S12进行Al元素掺杂，优化其电化学稳定性。以Li，Ge，Al，P和S为原料，经过机械球磨工艺及后续热处理工艺，合成具有thio-LISICON结构的Li10AlxGe(1-3x/4)P2S12（x=0.1，0.2，0.3，0.4，0.5，0.6）固体电解质。采用XRD，SEM，EIS，CV等手段对该固体电解质的结构、形貌及电化学性能等进行表征，得到Al掺杂量为x=0.3时，该电解质的室温电导率最高为2.96×10-3 S·cm-1。测试其电流-电压曲线发现，Li10Al0.3Ge0.775P2S12的锂分解电压为+0.05 V，较LGPS低（LGPS的还原分解电压为+0.1 V左右）。说明Al元素的掺杂有效降低了LGPS电解质的还原分解电压，使该电解质有更好的电化学稳定性。LiCoO2在全固态电池Li/Li10Al0.3Ge0.775P2S12/LiCoO2中的首次放电容量为106.0 mAh·g-1（20圈循环后容量保持率为89.9%）;Among inorganic solid electrolytes, sulfide solid electrolytes have many advantages, such as high lithium ionic conductivity at room temperature, wide electrochemical window (>5.0 V vs. Li+/Li), and good stability for lithium metal. Therefore, sulfide solid electrolyte has excellent application prospects in the new generation of lithium batteries. However, there are still some problems to be solved: 1) raw material Li2S has high purity requirement, complex preparation process and high price; 2) synthesis process of ternary sulfide solid electrolyte needs to be optimized; 3) electrochemical stability of ternary sulfide solid electrolyte needs to be further improved. In order to solve the above problems, an optimized synthesis process and element doping method are used to improve the structural stability and electrochemical stability of sulfide solid electrolyte. The main research contents are as follows.(1) Li2S synthesized by high-energy ball milling.In the glove box filled with Ar (H2O<1 ppm, O2<1 ppm), lithium and sublimated sulfur powder were mixed and weighed for high-energy ball milling. The experimental results show that the optimum milling time is 180 min and the optimum raw material ratio is Li=0.42 g and S=1.00 g under the condition of 370 rpm rotational speed. The Li2S powder prepared by this method has high purity whose XRD diffraction peak is consistent with the standard peak.(2) Optimized synthesis of ternary sulfide solid electrolyte Li10GeP2S12 (LGPS).The raw materials were weighed and mixed in a glove box filled with Ar (H2O<1 ppm, O2<1 ppm) at the molar ratio of Li:Ge:P:S=10:1:2:24, considering sublimation, sulfur needed excessive. Li10GeP2S12 with thio-LISICON structure was synthesized by high energy ball milling and two-stage sintering process. The synthesized LGPS possesses regular morphology and uniform particle distribution without agglomeration. Simultaneously, it presents the room temperature conductivity σLi of 3.27×10-3 S cm-1, a low activation energy Ea of 25.5 kJ mol-1 and a wide electrochemical voltage window of over 6.0 V (vs. Li+/Li). The first discharge capacity and the capacity retention rate after 20 cycles of LiCoO2 in Li/LGPS/LiCoO2 solid-state battery are 119.6 mAh·g-1 and 89.6%. The new method with low cost, high efficiency and simple process can well replace the traditional method. The LGPS synthesized by the above method has broad application prospects in lithium-negative solid-state batteries.(3) The electrochemical stability of ternary sulfide solid electrolyte Li10GeP2S12 optimized by doping Al element.Li10AlxGe(1-3x/4)P2S12 (x=0.1, 0.2, 0.3, 0.4, 0.5, 0.6) solid electrolyte with thio-LISICON structure was synthesized from Li, Ge, Al, P and excess S by mechanical ball milling and subsequent heat treatment. The structure, morphology and electrochemical properties of the solid electrolyte were characterized by XRD, SEM, EIS and CV. The results show that the conductivity of the electrolyte at room temperature is the highest (2.96×10-3 S·cm-1) when the doping amount of Al is x=0.3. The cyclic voltammetry results show that the lithium decomposition voltage of Li10Al0.3Ge0.775P2S12 was +0.05 V, which is lower than LGPS (the reduction decomposition voltage of LGPS was +0.1 V). It shows that the doping of Al element effectively reduces the reduction decomposition voltage of LGPS electrolyte and makes the electrolyte with better electrochemical stability. The first discharge capacity and the capacity retention rate after 20 cycles of LiCoO2 in Li/Li10Al0.3Ge0.775P2S12/LiCoO2 solid-state battery are 106.0 mAh·g-1 and 89.9%.