CTAB作为钒电池电解液添加剂的研究

Characteristics of CTAB as Electrolyte Additive for Vanadium Redox Flow Battery

通过紫外-可见、扫描电镜、方波伏安、循环伏安、稳定性考察,研究了十六烷基三甲基溴化铵(CTAB)作为钒电池电解液的添加剂对电解液的稳定性和电化学活性的影响,并对其机理进行了探讨.研究结果表明:电解液中CTAB胶束的季铵头部基团与五价钒作用,阻止五价钒的进一步聚合,从而抑制了五价钒的结晶.同时,添加剂在电极和电解液界面上,形成稳定的半球状颗粒,起到胶束催化V(IV)/V(V)氧化还原电对的作用.交流阻抗、充放电测试表明添加CTAB的电解液大大减小电荷传递电阻,使双电层电容增大一倍,提高电解液的电化学反应活性,这与CTAB的胶束催化相吻合.

Hexadecyl trimethyl ammonium bromide（CTAB） was used as the additive in electrolyte for vanadium redox flow battery.Its stability and electrochemical performance were investigated by UV-Vis absorption spectrophotometry,scanning electron microscope（SEM）,square wave voltammetry（SWV）,cyclic voltammetry（CV） and examination of stabilization.The results show that the quaternary ammonium headgroups of CTAB micelles interacting with V（V） ions in electrolyte prevents pentavalent vanadium from further polymerization,which leads to a good suppression of the crystallization.The stable hemispherical particles forming at the graphite-liquid interface catalyze the redox reaction of V（IV）/V（V）,which is called Micellar catalysis.EIS and charge-discharge tests show that the adding of CTAB makes charge transfer resistance much smaller,and doubles double-layer capacitance,so that the electrochemical reaction activity of the electrolyte improved,which is consistent with CTAB micellar catalysis.