膨润土/硫复合材料在锂硫电池中的应用

Application of bentonite/S composite for lithium-sulfur batteries

以膨润土作为单质硫的载体,热处理得到含硫50%（质量分数）的膨润土/硫复合材料,采用X射线衍射、扫描电镜、透射电镜和比表面分析仪对复合材料进行结构、形貌和孔径分析,通过充放电性能测试和交流阻抗对锂硫电池进行电化学性能分析。电化学测试结果表明,在1.0-3.0V电压范围内,以0.2、0.5C大小的电流密度对电池进行充放电性能测试,首次放电比容量分别为795.6和586.0mAh/g,100次循环后对应的放电比容量分别为488.5和421.5mAh/g,容量保持率分别为61.3%和71.8%。

Bentonite/S composite with 50%sulfur for lithium-sulfur batteries is obtained by heat treatment with bentonite as carrier of element sulfur.The structure,morphology and pore size of the composite are characterized by X-ray diffraction（XRD）,scanning electron microscope（SEM）,transmission electron microscope（TEM）and Brunauer Emme-Teller（BET）techniques.The electrochemical properties of lithium-sulfur batteries are analyzed by charge-discharge and electrochemical impedance spectroscopy tests.It is shown that the first specific discharge capacity of bentonite-sulfur cathode is about 795.6mAh/g at 0.2Ccurrent rate in the voltage range of 1.0-3.0V,and it remains 488.5 mAh/g after 100 cycles,which is 61.3% of the initial cycle.Under0.5Ccurrent density,the first discharge capacity is 586.0 mAh/g,and maintains 421.5 mAh/g after 100 cycles,corresponding to 71.8% of the initial cycle.