含多碘化物的液流电池电解液电化学性质研究

Study on Electrochemical Properties of Electrolytes in Flow Batteries Containing Polyiodides

制备了多种不同浓度的常规碘化锌电解液、优化型电解液以及新型多碘化物电解液,对其进行循环伏安(CV)测试及电化学阻抗(EIS)测试。CV测试表明,以NaI、ZnCl_(2)为主要成分的优化型电解液和以Et_(3)SI为主要成分的新型多碘化物电解液具有良好的可逆性。EIS测试表明,电解液中添加ZnCl_(2)、ZnBr_(2)均可起到优化电解液、增强电化学性能的效果。常规碘化锌电解液与优化型电解液主要受离子扩散过程控制,新型多碘化物电解液主要受电化学过程控制。针对离子扩散过程较缓慢的常规碘化锌电解液和优化型电解液,应在进行液流电池流道结构设计时侧重加强其溶液内部的离子传递过程。对于新型多碘化物电解液,应在流道设计上侧重加强其在电极表面的电化学反应过程。

The conventional zinc iodide electrolyte,optimized electrolytes and new type of polyiodide electrolytes with different concentrations of substances were prepared and tested by cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS).CV testing shows that the optimized electrolytes with Nal and ZnCl_(2)as the main components and new polyiodide electrolytes with Et_(3)SI as the main component have good reversibility.EIS testing shows that adding ZnCl_(2)and ZnBr_(2)to the electrolyte can optimize the electrolyte and enhance electrochemical performance.The conventional zinc iodide electrolyte and optimized electrolytes are mainly controlled by ion diffusion processes,while new polyiodide electrolytes are mainly controlled by electrochemical processes.For conventional zinc iodide electrolytes and optimized electrolytes with slow ion diffusion processes,emphasis should be placed on strengthening the ion transfer process inside the solution when designing the flow battery channel structure.For the new type of polyiodide electrolyte,emphasis should be placed on enhancing its electrochemical reaction process on the electrode surface in the channel design.