Weatherability of soluble lead flow batteries using the electrolytes of Pb (CH3SO3)(2) and CH3SO3H/HBF4

摘要

An electrolyte of Pb(CH3SO3)(2) and CH3SO3H/HBF4 mixed acids is utilized to investigate the cycling performance of soluble lead flow batteries over the range -40 degrees C-50 degrees C. The solution containing 1.0 M Pb(CH3SO3)(2) + 0.4 M CH3SO3H + 1.6 M HBF4 is optimized as the electrolyte based on its freezing point, conductivity and dynamic viscosity. At low temperature, its charge transfer resistance is lower than that in Pb(CH3SO3)(2) + CH3SO3H solution. The side reactions of hydrogen and oxygen evolutions are reduced that is beneficial for the electrode-position of PbO2 and Pb. At high temperature, the hydrolysis of HBF4 could be inhibited by CH3SO3H. The corrosion current density is reduced to effectively avoid the corrosion and failure of graphite electrodes. The coulombic efficiency of cells is maintained at 87.3 -95.1 within the range -40 degrees C-50 degrees C. The energy efficiency is higher than 74 . The soluble lead flow battery exhibits an excellent weatherability.