Enhanced Catalysis of P-doped SnO₂ for the V²⁺/V³⁺ Redox Reaction in Vanadium Redox Flow Battery

In this work, nanosized P-doped SnO₂ (SnO₂-P) was prepared by a sol-gel method as a catalyst for the V³⁺/V²⁺ redox reaction in vanadium redox flow battery. Compared with SnO₂, the electrochemical performance of SnO₂-P is significantly improved. This is because P doping provides more active sites and shows greatly improved electrical conductivity, thereby increasing the electron transfer rate. As a result, SnO₂-P shows better catalytic performance than SnO₂. The SnO₂-P modified cell is designed, and it exhibits an increase of 47.2 mA h in discharge capacity and 8.7% in energy efficiency compared with the pristine cell at 150 mA cm^-2. These increases indicate that the modified cell has a higher electrolyte utilization rate. This study shows that SnO₂-P is a new and efficient catalyst for vanadium redox flow battery.