AQUEOUS POLYSULFIDE FLOW-THROUGH ELECTRODES - EFFECTS OF ELECTROCATALYST AND ELECTROLYTE-COMPOSITION ON PERFORMANCE

Porous electrodes are required to achieve satisfactory performance of the aqueous sulphide/polysulphide redox couple in energy conversion and storage applications. A flow cell for testing flow-through porous electrodes was constructed and operated. The effects of electrode material, temperature, flow rate, and electrolyte composition were studied. Catalytic electrode surface layers of Co and MoS2 demonstrated performances which were more than adequate to meet a design goal of 10-20 mA cm-2 at less than 50 mV overpotential. Flow rate variation had only a small effect on the current density-overpotential behaviour, whereas raising the temperature and/or adding dimethylformamide to the electrolyte had much larger effects. These observations are consistent with steady-state results obtained on rotating disc electrodes.