Enhanced Surface Area Carbon Cathodes for the Hydrogen–Bromine Redox Flow Battery

The hydrogen–bromine redox flow battery is a promising energy storage technology with the potential for capital costs as low 220 $ kWh−1 and high operational power densities in excess of 1.4 W cm−2. In this work, enhanced surface area bromine electrodes incorporating carbon black (CB) graphene nanoplatelets (GnPs) on paper cloth substrates were investigated, effect electrolyte concentration performance was studied. Carbon-black-modified are found to possess largest electrochemically active areas, i.e., up 11 times that unmodified materials, while GnP shown have superior kinetic activity towards electrode reaction. terms performance, lower concentrations favour improved parameters associated nanoplatelet electrodes, highly concentrated electrolytes larger electrodes. optimal achieved carbon-black-modified 6 M HBr/2 Br2 concentration, polarisation current approaching 1.6 A cm−2 at overpotentials ±400 mV, mean 364 mV during oxidation 343 reduction, resulting from oxidation/reduction cycling tests ±1.5