Perovskite enables high performance vanadium redox flow battery

Perovskites have been attractive materials in electrocatalysis due to their virtues of low cost, variety, and tuned activity. Herein, we firstly demonstrate superior electrochemical kinetics of LaBO3 (B = V, Cr, Mn) perovskites towards vanadium redox reactions in vanadium redox flow batteries (VRFBs). LaBO3 (B = V, Cr, Mn) perovskites present the intrinsic catalysis towards V3+/V2+ and VO2+/VO2+ redox reactions in order of LaMnO3 > LaCrO3 > LaVO3. The catalysis is primarily attributed to activity of B-O bindings and perovskite structure that effectively promote the adsorption of vanadium ions. Moreover, perovskite contributes more active sites to vanadium redox reactions, resulting in a boosted electron exchange for redox reactions. Full cell tests demonstrate an energy efficiency (EE) of 60% at 300 mA cm−2 using graphite felt/LaMnO3 (GF/LaMnO3) electrodes. At 200 mA cm−2, the GF/LaMnO3 electrodes allow a 20% increase in EE of the flow cell as compared to pristine GF. The underlying catalysis mechanism of perovskite for vanadium redox reactions is also elucidated by density function theory, which lays the groundwork for future research into development of perovskite family in VRFBs.