摘要
制备了一种新型固体电解质Li8.5Ga0.5GeP2S12。用XRD、SEM、恒电流间歇滴定技术(GITT)和恒电流恒电压测试对其物相、形貌、离子导电性、锂离子的扩散系数和电池的充放电特性等进行了分析。Li8.5Ga0.5GeP2S12属于三斜晶系,P1空间群;固态电解质锂离子电池在3.30V、4.01V、4.18V时锂离子扩散系数(14.4×10-10 cm2·s-1、1.47×10-10 cm2·s-1、0.58×10-10 cm2·s-1)和液态电解液组成的锂离子电池的离子扩散系数(17.4×10-10cm2·s-1、2.02×10-10 cm2·s-1、0.75×10-10 cm2·s-1)基本处于一个数量级;固态电解质Li8.5Ga0.5GeP2S12在低倍率下放电容量比液态电解质稍低,而在高倍率下放电容量比液态电解质要高;固态电解质Li8.5Ga0.5GeP2S12有很优异的耐高温安全性,在130℃、2h热箱实验中电池没发生明显体积变化,而相同条件下的液态电解质锂离子电池已发生严重涨气。
Li8.5Ga0.5GeP2S12 as the electrolyte for Li-ion batteries was prepared. The phase, morphology, ion conductivity, Li-ion diffusion coefficient and electrochemical performance of Li8.5Ga0.5GeP2S12 samples were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, galvanostatic intermittent titration technique （GITT） and galvanostatic charge-discharge test. The results showed that, Li8.5Ga0.5GeP2S12 solid electrolyte can be assigned to triclinic system of space group P1 and has an Li ion diffusion coefficient 14.4×10-10cm2·s-1、1.47×10-10cm2·s-1、0.58×10-10cm2·s-1 at 3. 30 V,4. 01 V,4. 18 V respectively at an order of magnitude with that of liquid electrolyte（17.4×10-10cm2·s-1、2.02×10-10cm2·s-1、0.75×10-10cm2·s-1 at 3.30 V,4. 01 V,4. 18 V respectively）. Discharge capacity of Li8.5Ga0.5GeP2S12 was slightly lower than liquid electrolyte at lower current rate, but higher than liquid electrolyte at higher current rate. Li8.5Ga0.5GeP2S12 solid electrolyte has good high temperature stability, there is no volume change at 130 ℃ for 2 h, while the liquid batteries was seriously swelled at the same conditions.
基金
四川教育厅基金(11ZA165)
绵阳师范学院支持项目(2011D01)
关键词
固态电解质
扩散系数
离子电导
电化学性能
solid electrolyte, diffusion coefficient, ion conductivity, electrochemical performance
