化学学报 ›› 2009, Vol. 67 ›› Issue (24): 2815-2821. 上一篇    下一篇

研究论文

功能添加剂对锂离子电池的防过充电化学行为研究

曾彪,刘素琴,黄可龙,王海燕,黄建函,刘建生   

  1. 湖南长沙 中南大学
  • 投稿日期:2009-02-05 修回日期:2009-05-11 发布日期:2010-02-04
  • 通讯作者: 曾彪 E-mail:zengbiao1221@126.com
  • 基金资助:

    国家自然科学基金(200804058);广东省教育部产学研结合项目基金(NO:2007A090302034)

Electrochemical Behavior of Function Additive for Overcharge Protection of Li-Ion Batteries

  • Received:2009-02-05 Revised:2009-05-11 Published:2010-02-04
  • Contact: Zeng Biao E-mail:zengbiao1221@126.com

研究了功能添加剂3-氯苯甲醚(3CA)和联苯(BP)联合使用在锂离子电池电解液中的防过充行为。通过采用微电极循环伏安法、动电位扫描分析、扫描电镜法和充放电法等手段研究表明:联苯和3-氯苯甲醚混合添加剂的聚合电位随3-氯苯甲醚含量的增加由4.7V前移至4.6V (vs. Li/Li+);电池在正常工作电压(2.75V~4.2V)下,添加剂不参与电池反应过程;当电压高于4.2V电池发生过充时,3-氯苯甲醚在电极表面首先发生氧化还原飞梭分流限压对电池进行过充保护;电压继续升高时,联苯在电极表面发生电聚合反应,生成的聚合膜表面光滑致密是电子的良导体能有效的阻止Li+的嵌入与脱出,并通过自放电使电池处于安全状态,防止电池过充发生爆炸。两种防过充机制共同作用,对电池实施多重护防,提高了电池的安全性能。

关键词: 锂离子电池, 电解液添加剂, 过充保护, 联苯, 3-氯苯甲醚

The overcharge protection and electrochemical property of lithium ion batteries were studied by
microelectrode voltammetry, potentiodynamic polarization experiments, charge-discharge measurements
and SEM characterization of cell components, when functional additives such as biphenyl (BP) and
3-chloroanisole (3CA) were co-used in the electrolyte. The experimental results reveal that the polymerization
potential of electrolyte with mixed additives was moved forward from 4.7 to 4.6 V, as the content of
3-chloroanisole increased. When overcharged, 3-chloroanisole molecules were oxidized in the form of redox
shuttle reaction at the positive electrode, but biphenyl molecules were polymerized forming a compact film
on the surface of electrode. This film formed can effectively prevent the insertion and extraction of Li+. In
this way, the safety performance of lithium ion batteries can be improved by the co-use of the two additives
with different overcharge protection mechanisms.

Key words: lithium ion battery, electrolyte additive, overcharge protection, biphenyl, 3-chloroanisole