锂离子电池高电压正极粘结剂的研究进展

Advances of High-voltage Cathode Binders for Lithium Ion Batteries

锂离子电池在高电压下会导致严重的电解液分解以及不稳定的正极与电解质界面问题,严重制约高电压正极材料的商业化.粘结剂不仅可以将正极活性材料和导电炭紧密粘结在集流体上,还对构建电解质与正极之间的多尺度相容性界面起积极作用,因此,粘结剂的优化可以有效解决上述难题.本文提出了高电压锂离子电池正极粘结剂需具备的必要条件,如:粘结性能和机械性能优异,具有出色的电化学稳定性和热力学稳定性以及良好的离子和电子传输能力等.综述了近些年来高电压正极粘结剂的研究及发展现状,通过天然粘结剂和合成粘结剂对目前已报道的高电压粘结剂进行了评述,介绍了各种粘结剂对电极的粘结性能和包覆以及对锂离子电池性能的影响机制,重点阐述了粘结剂分子结构中的极性基团与活性物质间的相互作用,如氢键和离子-偶极相互作用,并讨论了设计开发高电压正极粘结剂的途径以及展望了高电压正极粘结剂的发展前景.

Lithium ion batteries(LIBs)generally suffer from severe electrolyte decomposition and the unstable cathode and electrolyte interface(CEI)during high voltage cycling,seriously impeding their practical applications.Binders can not only tightly bind the cathode active materials and conductive carbons onto the current collector,but also play a positive role in the construction of multi-scale compatible CEI.Thus,theoretically,the optimization of binders can effectively solve the above problems.In this review,we present the requirements of high voltage cathode binders,including excellent adhesion and mechanical properties,electrochemical stability and thermal stability,as well as good ion and electron transport capacity,review the high voltage cathode binders reported at present through natural binders and synthetic binders and summarize the recent research progress and development status of binders for high voltage LIBs along with the action mechanisms of various binders on the bonding and coating of electrodes and the performance of LIBs.Furthermore,we elaborate the interactions between the polar groups of binders and the cathode active particles,such as hydrogen bonding and ion dipole interaction.Finally,some perspectives and directions on future development of state-of-the-art binders for high voltage LIBs are discussed.