基于螯合B类锂盐的固态聚合物电解质的合成及其性能

Synthesis and performance of solid polymer electrolytes based on chelated boron lithium salts

全固态锂离子电池具有较高的安全性和优异的储能性等优点而发展迅速。螯合B类锂盐具有较大的阴离子半径,是固态聚合物电解质(SPE)的一种新型锂盐,它能够很好地破坏PEO、TPU等基体的结晶度,使更多的Li+能够与PEO、TPU等基体的高分子链段结合发生配位作用,提高锂离子电解质的解离能力。本研究利用螯合B类锂盐与PEO/TPU/BaTiO3组成SPE,测试SPE的形貌与结构、力学性能、热力学性能、电化学性能和电池性能,结果表明邻苯二酚丙二酸硼酸锂盐(LiBDMB)体系的SPE性能最佳。60℃下,LiBDMB体系的SPE离子电导率达到了10-4 S/cm数量级,组装的电池在0.2 C倍率下能达到142 mW·h/g的放电能力,并在50次循环后表现良好。

All-solid-state lithium-ion batteries have developed rapidly due to improved safety performance and energy storage capabilities.Chelated boron lithium salt is a new type of solid polymer electrolyte(SPE)with a larger anionic radius.It can disrupt the crystallinity of the matrix,such as polyethylene oxide(PEO)or thermoplastic polyurethane(TPU),so that more lithium ions can intercalate into the polymer segments of the matrix and therefore improve the dissociation of lithiumion in the electrolyte.This study used chelated boron lithium salt and PEO/TPU/BaTiO3 to form the SPE.Analysis of the morphology and structure,mechanical properties,thermodynamic properties,electrochemical properties,and battery performance showed that the lithium[(1,2-benzenediolate(2)-O,O′)(1,3-malonate-O,O′)]borate(LiBDMB)system gives the best SPE performance.At 60℃,the ion conductivity of the LiBDMB SPE system reached the order of 10-4 S/cm.The discharge capacity of the assembled battery reached 142 mW·h/g at a rate of 0.2 C and performed well after 50 cycles.