七甲基二硅氮烷对锰酸锂电池储存性能的影响

摘要

为改善锰酸锂的储存性能,以七甲基二硅氮烷为电解液添加剂、自制的LiPF6/EC+DMC+EMC为电解液,研究不同温度下七甲基二硅氮烷对不同荷电态的锰酸锂电池储存性能的影响,并采用扫描电镜、EIS及充放电方法对电极表面形貌及电池电化学性能进行表征和测试.实验结果表明:锰酸锂电池在常温和高温储存1周后,处于放电态电池的循环性能均比处于半电态和满电态的电池的循环性能更优异.放电态的锰酸锂电池常温储存1月后,首次充放电效率为95.22％,2C倍率下循环200次后,容量保持率为96.74％,与电解液中未加七甲基二硅氮烷的锰酸锂电池相比,表现出较好的储存性能.%The electrolyte of 1 mol/L LiPF6/EC+DMC+EMC was prepared, and the effect of heptamethyldisilazane as an electrolyte additive on the storage performance of LiMn2O4/Li cells with different charged states was investigated at different temperatures. Meanwhile, the morphology of cathode electrode surface and electrochemical performances of the cells were characterized and measured by SEM, EIS and charge-discharge method, respectively. The results show that the LiMn2O4/Li cells with discharged state after storage for a week at room temperature and elevated temperature have better cycling performance than the cells with half-discharged and full charged state. Moreover, the initial coulomb efficiency of the LiMn2O4/Li cells after storage for a month at room temperature is 95.22%, and the capacity retention is 96.74% after 200 cycles at 2C rate, showing better storage performance compared with the cells without heptamethyldisilazane in the original electrolyte.