钒电池电解液中杂质离子对电池性能的影响

Influence of Impurity Ions in the Electrolyte on Vanadium Battery Performance

为研究电解液中杂质离子对电池性能的影响,综合考虑电解液原材料以及电池运行过程可能引入的杂质种类,选取了SiO_3^(2-)和Fe^(2+)两种典型离子作为研究对象,利用循环伏安和充放电测试方法,考察其对石墨电极电化学活性、电池库仑效率、电压效率、能量效率和容量衰减的影响,为电解液的制备和使用过程中杂质离子控制提供理论依据。结果表明Fe^(2+)对正负极电极反应活性和电池效率没有影响,Fe^(2+)的加入提高了电池容量,容量值的提高与Fe^(2+)浓度有关;SiO_3^(2-)降低了电极反应活性、电压效率和能量效率,并且加速电池容量的衰减。因此,在钒电池电解液的制备和使用过程中,应尽量避免引入SiO_3^(2-)。

： Study on the influence of impurity ions in electrolyte is critical for optimizing and improving the performance of vanadium battery. Considering electrolyte materials and operation of vanadium batter- y, two typical ions, SiO32- and Fe2~, were selected as the research object. The influences of SiO32- and Fe2＋ on electrochemical activity of graphite electrode and coulombic efficiency, voltage efficiency, energy efficiency and capacity attenuation of battery were investigated by cyclic voltammetry and charge-dis- charge test, aiming to provide theory basis for the impurity ions control in electrolyte. The results suggest that Fe2~ does not affect： the reaction activities of the electrodes and battery efficiency, and the capacity of battery is improved by adding Fe2~. Nevertheless, SiO32- reduces the reaction activity, voltage and ener- gy efficiency of the electrodes and accelerates the rate of capacity attenuation of battery. Thus, SiOa2- should be avoided during the manufacture and use of vanadium electrolyte.