4-溴苯甲醚用作锂离子电池过充保护添加剂的研究

通过在锂离子电池电解液中添加4-溴苯甲醚(4-Bromoanisole, 简称4BA)来提高锂离子电池的过充保护能力. 对电池分别进行了过充实验、循环伏安扫描、红外光谱分析、交流阻抗和容量特性测试, 实验结果表明, 在1 mol•L－1 LiPF6/EC＋DEC＋DMC(质量比1/1/1)中添加5% 的4BA(质量分数)时, 当外加电压为4.4 V(相对于Li/Li＋)时, 4BA开始发生电聚合反应且生成高分子聚合物膜, 使电池内阻增大而阻止电压的升高, 从而使电池处于比较安全的状态. 该体系正常充放电过程中, 添加5%的4BA对电池容量特性基本没有影响, 4BA 的防过充机理为阻断机理.

4-Bromoanisole as a New Overcharge Protection Additive of Lithium-ion Batteries

In order to improve the ability of overcharge protection, 4BA was added as a novel electropolymerizable additive to the electrolyte of lithium-ion batteries. Proved by overcharge of batteries, cyclic voltammetry, infrared spectra, AC impedance tests, and discharge capacity measurements in this research, the overcharge protection ability of this novel additive was confirmed. When the external potential was 4.4 V, 4BA (5% by mass) in the system of electrolyte 1 mol•L－1 LiPF6/ EC＋DEC＋DMC (1/1/1, m/m/m) started to electrochemically polymerize and produced a layer of polymer film, which increased the internal resistance and prevented the voltage from dramatically rising up. Therefore, the lithium-ion batteries can be much safer. During the normal charge-discharge processes of the battery system, the addition of the proper weight percentage of 4BA does not have negative effect on the capacity of lithium-ion batteries, and the mechanism of overcharge protection is an interdiction mechanism.