锂离子电池过充短路添加剂

Additive of overcharge short-circuit for Li-ion battery

为了提高锂离子电池的抗过充性能,研究了二苯醚做为锂离子电池过充短路添加剂的性质。实验结果表明在锂离子电池有机电解液中,当电极电位高于4.5V(vs.Li/Li+)时二苯醚在铂盘电极上发生电氧化聚合,形成具有良好电化学活性的导电聚合物,同时LiMn2O4粉末微电极的结果表明在电极电位到达4.25V之前,二苯醚没有对正极材料产生明显的不利影响。LiMn2O4/Li模拟电池的结果表明当电池过充到约4.5V时,电池电压不再升高,同时扫描电子显微镜观察发现二苯醚在正极上发生了聚合。此外在聚合过程中产生的H+在负极上被还原为H2,增加了电池的内压,因此可以通过激活安全阀提高锂离子电池的安全性。

In order to improve the overcharge tolerance of Li-ion batteries, diphenyl ether as additive of overcharge short-circuit of Li-ion batteries was studied. Experimental results show that diphenyl ether can be electro-oxidized at around 4.5 V （vs.Li/Li^＋） on Pt plate electrode in the organic electrolyte of Li-ion battery, and the polymer with excellent electrochemical activity is formed. Diphenyl ether has no obvious detrimental effect on the positive electrode material until 4.25 V by the LiMn204 powder microelectrode. The result of simulated LiMn204/Li cell shows that when the overcharge voltage reaches around 4.5 V, the cell voltage will not increase; at the same time, diphenyl ether is found to be electo-polymedzed on the positive electrode from the observation of scanning electron microscope. Moreover, the produced H~ during polymerizing is reduced to H2 on the negative electrode, the internal pressure of batteries is raised, so the safety of Li-ion battery can be improved by activating safety valve.