聚碳酸酯基固态聚合物电解质的研究进展

液态锂离子电池由于采用易泄露、易挥发、易燃烧的碳酸酯有机溶剂,在高温或极端条件下使用时,存在极大的安全隐患.使用固态电解质替代液态电解液,可以从根本上避免此类安全问题的发生,与此同时还可以大幅度提升固态锂电池的能量密度.固态电解质又分为无机固态电解质和聚合物固态电解质2大类.无机固态电解质能够在宽的温度范围内保持化学稳定性,并且电化学窗口较宽,机械强度更高,室温离子电导率较高,但脆性较大,柔韧性差,制备工艺复杂,成本较高.聚合物固态电解质,室温离子电导率偏低,难以满足室温锂离子电池的应用,但其加工成型容易,形状可变.比较而言,固态聚合物电解质,更适宜大规模生产,离产业化相对更近.固态聚合物电解质中研究较多的是聚醚基固态聚合物电解质(如聚环氧乙烷和聚环氧丙烷),但其缺点是室温离子电导率低,需要对其改性或进一步开发综合性能更加优异的其他固态聚合物电解质.聚碳酸酯基固态聚合物电解质由于其特殊的分子结构(含有强极性碳酸酯基团)以及高介电常数,可以有效减弱阴阳离子间的相互作用,提高载流子数量,从而提高离子电导率,因此被认为是一类非常有前途的固态聚合物电解质体系.基于此,本文重点综述了最近研究热点的聚碳酸酯基固态聚合物电解质,包括聚(三亚甲基碳酸酯)体系、聚(碳酸丙烯酯)体系、聚(碳酸乙烯酯)体系和聚(碳酸亚乙烯酯)体系等,并详细阐述了上述每种聚碳酸酯基固态聚合物电解质的制备、电化学性能、优缺点及改性手段,归纳出其离子配位-解配位过程和离子扩散机制,还对聚碳酸酯基固态聚合物电解质的未来发展方向和研究趋势望进行了预测和展望.

Research Progress on Polycarbonate-based Solid-state Polymer Electrolytes

Rechargeable lithium ion batteries become an very important technology in the contemporary society.They are expanding their application in electric vehicles and power grids.However,current lithium ion batteries with liquid electrolyte have been suffering from potential safety crisis mainly due to their highly flammable organic liquid carbonate organic electrolyte and explosion hazards.These potential risks (combustion and explosion) would retard the commercialization of electric vehicles or hybrid electric vehicles.Thus,the safety issue of lithium ion battery merits further study.Solid electrolytes have attracted ever-increasing interest owing to their enhanced safety issue and higher energy density of lithium battery.Solid electrolyte materials mainly include inorganic solid electrolytes (ISEs) and solid polymer electrolytes (SPEs).The ISEs are classified into oxide-based,sulfide-based and etc.However,in spite of the presence of highly ion conductive ISEs,there are still many undergoing issues that limit the practical application at the present stage,like the large interface impedance between electrode and ISEs and the difficulty of processing.More attention has been paid to solid polymer electrolytes due to their superior flexibility and processability,which are also subjected to thermal expansion at elevated temperature.Poly(ethylene oxide) (PEO) solid polymer electrolyte has undergone a sort of renaissance in the past few decades.However,the quintessential frailty of PEO solid polymer electrolyte is low ionic conductivity (in the order of 10-7 S cm-1) at room temperature with a relatively narrow electrochemical window.Hence,it is essential to develop new solid polymer electrolytes with comprehensive performance in terms of high ionic conductivity,wide electrochemical window,superior mechanical strength,excellent thermal stability as well as good interfacial compatibility.In this review,a series of polycarbonate-based solid polymer electrolytes (such as PEC,PPC,PTMC and PVC et al.) are summarized.In addition,we also present a brief review on preparation,electrochemical property,modification,ionic transportation mechanism and future development direction for each of these solid polymer electrolytes.