SDS作为正极电解液添加剂对钒电池性能的影响

Effect of SDS as an additive of positive electrolyte on performance of vanadium battery

为优化钒电池正极电解液的性能,以十二烷基磺酸钠(SDS)作为钒电池正极电解液添加剂,研究不同质量分数的SDS对钒电池正极电解液的运动粘度、电导率、热稳定性以及电化学性能的影响.结果表明:正极电解液的运动粘度随添加剂质量分数的增大而逐步增大,而导电率随SDS质量分数的增加先增大至3%处的最大值372mS·cm-1后再减小;SDS可以延缓V5+离子在高温下的沉淀速度,SDS质量分数为3%时,V5+离子的热稳定性最好;扫速为50mV·s-1下循环伏安测试表明,含添加剂w(SDS)=3%的电解液氧化峰和还原峰电流最大,分别为163.8、142.2mA,电化学性能最佳;以w(SDS)=3%的电解液作为钒电池的正极电解液,电流密度为20mA·cm-1下50次充放电循环的平均容量比空白的提高50.2%,容量保持率和平均能量效率都优越于空白电池.

In order to optimize the performance of vanadium battery with positive electrolyte （sodium dodecyl sulfonate SDS） was employed as an additive to positive electrolyte to investigate the effect of SDS content on the kinematic viscosity,conductivity,thermal stability and electrochemical performance of the electrolyte.The result showed that kinetic viscosity was gradually increased with SDS content,while conductivity was increased first to the maximum value of 372 mS · cm-1 （SDS content：3％） with SDS content and then decreased.The precipitating of Vs＋ could be delayed by SDS and the V5＋ showed an optimal thermal stability when the SDS content was 3％.Cyclic voltammetry test showed that the electrolyte with 3％ SDS possessed optimal electrochemical activity with the highest anodic peak current （163.8 mA） and cathodic peak current （142.2 mA） in case of scan rate of 50 mV · s-1.The average discharge capacity of the cell with positive electrolyte with 3％ SDS was 50.2％ higher than the blank one,and the capacity retention ratio （85.4％） and average energy efficiency （83.1％） were both superior to the blank one （61.0 ％ and 79.2％,respectively） in case of current density of 20 mA cm-1.