An alternative HCMS carbon catalyst in bromine reduction reaction for hydrogen-bromine flow batteries

Abstract In this study, significantly active hollow core mesoporous shell (HCMS) carbon catalysts are synthesized for the hydrogen-bromine flow battery cathode electrode. As an alternative to cathode catalysts such as Pt/C or carbon black, high surface area HCMS carbons are synthesized and its effect on hydrogen-bromine flow battery performance has been investigated for grid-scale energy storage for the first time. HCMS carbon is synthesized by template replication of the solid core mesoporous shell silica spheres. By changing the amount of TEOS (1 mL, 6 mL, 10 mL) used during silica template formation, carbons with different core/shell structures have been produced (HCMS1, HCMS6, HCMS10). Structural characterizations of the synthesized cathode catalysts have been performed with SEM, TEM, and N2 adsorption analyses. Electrochemical characterization of catalysts has been performed by cyclic voltammetry analyses and flow battery performance tests. 0.50 W/cm2 peak power density obtained with HCMS1 carbon is promising compared to Pt-based catalysts and commercial carbons.