Advanced electrode decorated with peanut-shell-derived carbon for vanadium redox flow battery

Abstract

Vanadium redox flow batteries (VRFBs) have been regarded as one of the most promising energy storage systems at grid-scale owing to their advantages of safe operation, flexible design, and long cycle life. However, the low electrochemical activities and poor hydrophilicity of conventional carbon-based electrodes (e.g., carbon felt, CF) greatly restrict the further improvements of cell performance and commercial applications. Therefore, fabricating advanced electrodes is crucial to the progress and practical applications of VRFBs. In this work, the waste biomass of peanut shells (PS) is used as the raw material to produce carbon particles that coat on the surface of CF (PS/CF) via adsorption and carbonization procedures. The redox reactions of VO2+/VO2+ are remarkably promoted on the as-prepared PS/CF electrode. When PS/CF is employed as the positive electrode, the resulting VRFB cell shows energy efficiency of 87% over 500 cycles under 100 mA cm−2, which is significantly higher than the pristine CF-based VRFB cell (79%). Additionally, the cycling stability of PS/CF-based cell has been remarkably enhanced. This study demonstrates that the cost-effective and sustainable peanut-shell-derived carbon modified CF holds a broad application prospects in the practical applications of advanced VRFBs as energy storage systems.