以LiNO3、Al(NO3)3、ZrO(NO3)2、NH4H2PO4、Ti(OC4H9)4为原料,采用修饰的溶胶凝胶法制备出NASICON型固态电解质Li1.4Al0.4ZrxTi1.6-x(PO4)3(LAZTP),通过烧结得到固态电解质片。研究了Zr^4+掺杂取代Ti^ 4+对固态电解质性能的影响。分别采用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、电化学阻抗谱(EIS)表征了固态电解质的结构和电化学性能。结果表明,固体电解质Li1.4Al0.4ZrxTi1.6-x(PO4)3在掺Zr量为x=0.1时具有最高的纯度、好的致密度(98%)和高的离子电导率(体电导率和总电导率分别为2.8×10^-3 S/cm、1.4×10^-3 S/cm)。将该样品用作锂硫电池的电解质并采用恒流充放电法测试电池的电化学性能,电池在50mA/g的电流密度下首次可逆容量为1187mAh/g,循环40次后可逆容量仍达990mAh/g,显示出比液态锂硫电池更好的充放电性能和循环稳定性。
NASICON solid electrolyte Li1.4A10.4ZrxTi1.6-x(PO4)3 was prepared by a modified sol-gel method using LiNO3, Al(NO3)3, ZrO(NO3)2, NH4H2PO4, Ti(OC4H9)4 as raw materials. The influence of Zr^4+ doping on the performance of solid electrolyte was studied. The structure and electrochemical performance of the prepared electrolyte were investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and electrochemical impedance spectroscopy (EIS). The results showed that the solid electrolyte Li1.4A10.4ZrxTi1.6-x(PO4)3 had the highest purity, density (relative density of 98%) and ion conductivity (bulk and total Li^+ conductivities are 2. 8×10^-3 S/cm and 1.4× 10^-3 S/cm, respectively) when Zr-doping content x was 0. 1. The Li1.4A10.4ZrxTi1.6-x(PO4)3(x=0. 1) was used as electrolyte of lithium-sulfur (Li-S) battery, and the electrochemical performance of the battery was tested by method of galvanostatic discharge. In the first charge-discharge cycle, its reversible capacity at charge/discharge current density of 50 mA/g was 1187 mAh/g, and it could still reach 990 mAh/g after 40 cycles. Compared with liquid battery, the solid battery has a better charge-discharge performance and cycling stability.