有机弱酸添加剂稳定全钒液流电池正极电解液的微观机制  

Mechanism of weak organic acid additive stabilizing positive electrolyte of vanadium redox flow battery

作　　者：王长生[1] 李艳敏 田凤玉[1] WANG Changsheng;LI Yanmin;TIAN Fengyu(School of Chemistry and Chemical Engineering,Liaoning Normal University,Dalian 116029,China)

机构地区：[1]辽宁师范大学化学化工学院

出　　处：《辽宁师范大学学报（自然科学版）》2020年第1期51-55,共5页Journal of Liaoning Normal University:Natural Science Edition

基　　金：国家自然科学基金资助项目(21773102)

摘　　要：正极电解液是全钒氧化还原液流电池的重要组成部分,对电池性能有直接影响.随着温度升高,电解液中的五价钒离子以五氧化二钒形式生成沉淀,导致电池性能变差.使用少量添加剂可以提高正极电解液稳定性,但其微观机制尚未明确.使用密度泛函理论方法探讨了草酸盐、醋酸盐、柠檬酸盐等有机弱酸盐添加剂对正极电解液稳定性的影响,尝试从分子水平理解添加剂提高钒电池效率的微观机制.研究发现:草酸盐、醋酸盐和柠檬酸盐等添加剂可与电解液中的五价钒物种发生反应,其反应势垒低于形成五氧化二钒的势垒,减少了五氧化二钒的生成概率,从而提高了正极电解液的稳定性.The positive electrolyte is one of the most important components of vanadium redox flow battery and directly impacts the performance of the battery.When the temperature rises,the most stable vanadium-containing species[VO(OH)2·H2O]^+ in electrolyte will form the precipitates of V2O5 and damage the battery.It is known that certain additives could improve the stability of the positive electrolyte,but the mechanism has not yet been clarified.In this paper,density functional theory method is used to study the effect of oxalate,acetate and citrate additives on the stability of the positive electrolyte,trying to understand the mechanism at the molecule level.It is found that oxalate,acetate and citrate additives can react with the[VO(OH)2·H2O]^+ in electrolyte,and the reaction barrier of which is lower than that of forming V2O5,thereby avoid the precipitation and improve the battery efficiency.

关 键 词：液流电池 添加剂 电解液 密度泛函理论 反应势垒 

分 类 号：O641.121[理学—物理化学]