PAA类黏结剂在锂电池中电化学性能研究进展

Research progress in electrochemical properties of lithium batteries with PAA binders

黏结剂是维持极片完整性必不可少的部分,对电池比容量、循环稳定等性能的提高非常重要。聚丙烯酸(PAA)因含有较多极性官能团,可溶于水,而被用作锂电池正负极黏结剂。PAA黏附性好,但极性基团使得分子链间形成的氢键导致PAA链刚性较大,不利于维持充放电过程中极片的完整性,因此,控制PAA官能团数量、改变官能团种类及PAA分子链结构,对锂电池电性能的提高势在必行。本文综述了近几年锂电池用PAA黏结剂的研究进展,重点介绍了PAA黏结剂的结构特性、改性及应用方式及其对不同种锂电池首次库伦效率、循环稳定性和阻抗性能的影响,并对PAA黏结剂的未来改性研究热点做了展望,探索PAA引入不同结构的弹性或导电聚合物后,对于黏结剂本身性能的影响,改善界面性能,以适用于不同活性材料正负极,提高锂离子传输速率,更好地提高锂电池的使用性能。

Electrode binder is an essential part to maintain the integrity of electrode,and it is very important to improve the specific capacity and cycle stability of the battery.Polyacrylic acid(PAA)is widely used as the binder of anode or cathode in the lithium batteries because it contains more polar functional groups and can be dissolved in water.Due to possessing a lot of polar groups,PAA binder has better adhesion.But the hydrogen bond formed between the molecular chains by polar groups makes the PAA molecular chain more rigid,which is not conducive to maintaining the integrity of the electrodes during charging and discharging.It indicates that controlling the number of PAA functional groups and changing the type of functional groups/molecular chain structure of PAA binder have a great influence on the improvement of battery performance.The effect of PAA binder on electrochemical performance of lithium battery in recent years was reviewed in this paper,focusing on the structural characteristics,modification and application methods and their effects on the initial coulombic efficiency,cycling stability and impedance of different lithium batteries.Perspectives on the future of modified PAA binder were reviewed.The effects on the performance of the binder were explored after introducing different structures such as elastic or conductive groups.Improving the interface performance is to be suitable for cathode and anode with different active materials,and to improve the lithium ion diffusion coefficient.Then the performance of lithium battery is also enhanced.