金属氢氧化物对锂硫电池性能的影响

摘要

通过水热法在锂硫电池正极材料硫碳复合物表面包覆纳米金属氢氧化物抑制多硫化物的穿梭,很好地改善了电池的循环性能.利用扫描电镜(SEM)、恒流充放电和交流阻抗等方法比较了不同包覆层氢氧化铝、氢氧化钴、氢氧化铈对锂硫电池性能的影响.其中,用氢氧化铝包覆的硫碳复合材料显示了较好的电化学性能,在100 mA/g充放电条件下,首次充放电比容量为1 192 mAh/g,80次循环后放电比容量为797 mAh/g,容量保持率达67％.0.5 C条件下,放电比容量达754 mAh/g.%In this study,it is encapsulated nano metal hydroxide on the surface of SC by the method of hydrothermal.The nano metal hydroxide could inhibit polysulphide shuttle,which improved the cycle performance of lithium sulfur batteries.The influence of Al(OH)3,Co(OH)2,Ce(OH)3 on electrochemical performance of Li-S cells was investigated by constant current discharged,AC impedance and scanning electron microscopy(SEM).It was found that Al(OH)3-coated SC displayed the better electrochemical performance.It exhibited a discharge specific capacity of 1 192 mAh/g and capacity retention of 67％ after 80 cycles at a current density of 100 mA/g,which is much higher than other materials.Meanwhile,Al(OH)3-coated SC shows the best rate performance of 754 mAh/g at 0.5 C.