基于可逆热响应智能电解液的电化学储能器件过热自保护作用机制研究

安全问题是制约大容量、高功率密度电化学储能器件发展的关键瓶颈。本项目提出利用热响应聚合物在电解液中溶胶-凝胶转变对离子导电的影响，消除或抑制储能器件热失控的思路。拟分别合成在超级电容器水系电解液中具有LCST行为的两亲性嵌段共聚物和带有温敏段、在锂电池离子液体电解液体系中具有LCST行为的嵌段共聚物凝胶。阐明嵌段共聚物结构在不同电解液中对溶胶-凝胶相转变温度和热响应速度的影响规律，揭示热可逆嵌段共聚物在电解液中的构象变化、自组装行为以及对导电离子传输的影响机理及相关电化学性能的作用关系，获得可逆热响应智能电解液体系的多功能特性和过热自保护作用机制。在此基础上通过调控嵌段共聚物的嵌段比例、对称性、相对分子质量、浓度等使溶胶-凝胶相转变温度可调，并在发生热失控时具有快速热响应，从而达到对储能器件热失控的有效控制，为解决目前电化学储能器件的安全问题，建立一种主动的可逆过热保护技术奠定理论基础。

A major stumbling block in large-scale adoption of high-energy-density and rapid charge/discharge electrochemical storage devices has been safety issues. Herein we pretend to develop a simple and reversible thermo-responsive electrolyte system that is efficient to shut down the current flow, according to that specific block copolymers would show sol-gel transition at elevated temperature to affect the migration of conductive ions. In this program thermo-responsive block copolymers that show LCST behaviors in corresponding specific electrolyte of supercapacitors and lithium batteries, respectively, are synthesized to prepare the reversible smart Electrolyte for self-protection. We are aiming at clarifying the influence of the architecture of block copolymer on the temperature and response rate of the sol-gel phase transition; revealing the conformation change and self-assemble behavior of the block copolymer in the electrolyte, which is closely related to the transport of the conductive ions; analyzing the relationship between the micro - macro structure of the electrolyte and the ionic conductivity. Based on the understanding of the relationship between the multi-function characteristics and the mechanism of autonomic switching behavior, this project is promise to achieve the control of sol-gel transition temperature and ionic conductivity, as well as fast thermos-response and efficient suppression of thermal runaway. This technical innovation would make a breakthrough in the development of reversible self- protection for next generation of electrochemical energy storage device.