尖晶石LiMn_(2)O_(4)高温电化学性能研究

Study on the electrochemical performance at high temperature for the spinel LiMn_(2)O_(4)

利用高温固相反应合成了锂离子蓄电池正极材料尖晶石LiMn2 O4 ,研究了在高温 5 5℃下LiMn2 O4 循环容量的衰减和贮存后电化学性能的变化。与常温下相比较 ,5 5℃下尖晶石的容量衰减显著加快 ,贮存后的LiMn2 O4 循环性能变差。改变合成工艺条件如合成温度、n(Li)∶n(Mn)比 ,LiMn2 O4 的高温电化学性能有所改善 ,掺杂金属Co元素合成尖晶石掺Co化合物也能够提高LiMn2 O4 在高温下的循环性能 ,通过测量LiMn2 O4 在高温下电解液中的溶解 ,分析了容量衰减的机理。

The performance of spinel LiMn 2O 4 synthesized by solid-state reaction at high temperature(55 ℃)was investigated.The cycling capability was poorer at 55 ℃ than at room temperature.The synthesis temperature and n(Li)∶n(Mn) ratio were found to have influence on the electrochemical performance of LiMn 2O 4.Also,the Co-doped spinel showed an enhanced cycling capability.The LiMn 2O 4 dissolution in the 1 mol·L -1 LiPF 6/EC+DMC was studied and the mechanism of capacity fading at 55 ℃ was thus analyzed.