Role of Bismuth in the Electrokinetics of Silicon Photocathodes for Solar Rechargeable Vanadium Redox Flow Batteries

The ability of crystalline Si to photo-assist the V3+/V2+ cathodic reaction under simulated solar irradiation, combined with the effect of Bi have led to important electrochemical improvements. Besides the photo-voltage supplied by the photovoltaics, additional decrease in the onset potentials, high reversibility of the V3+/V2+ redox pair and improvement in the electro-kinetics have been attained thanks to the addition of Bi. In fact, Bi0 deposition has shown to slightly decrease the photocurrent, but the significant betterment in the charge transfer, reflected in the overall electrochemical performance clearly justifies its use as additive in a photo-assisted system for maximizing the efficiency of solar charge to battery.