Synergistic catalysis of carbon/bismuth composite for V3+/V2+ reaction in vanadium redox flow battery

Biomass carbon materials have many advantages of wide source, environmental friendliness and low price. Herein, the carbon/bismuth composite (PHB) was employed as negative electrocatalyst for vanadium redox flow battery (VRFB). The composite was prepared by hydrothermal and high temperature treatment with pomelo peel and NaBiO 3 as raw materials for V 3+ /V 2+ redox reaction. Biomass carbon material exhibits large specific surface area, various oxygen-containing functional groups, and multiple reactive places. Metal bismuth can significantly inhibit the hydrogen evolution reaction, which can also provide abundant active sites. The composite catalyst not only inhibits the side reaction but also accelerates the kinetics in charge transfer and electron transport. Therefore, the composite catalyst can promote the comprehensive performance of negative electrode. At 150 mA cm −2 , the discharge capacity of the cell using PHB (88.5 mA h) is 36.8 mA h higher than the blank cell. Energy efficiency is increased by 9.1% after using PHB. This work provides a carbon/bismuth composite, which is a promising catalyst in VRFB.