Zinc Anode for Direct Borohydride Fuel Cells

Zinc is evaluated as a negative electrode for the direct electrochemical oxidation of sodium borohydride . Open-circuit potential measurements, cyclic voltammetry, chronoamperometry, and chronopotentiometry are used to characterize the electrode behavior, namely, the oxidation reaction at the Zn/borohydride interface. Two consecutive oxidation steps are identified, and a possible working mechanism is proposed. A relatively low electrocatalytic activity of Zn for borohydride oxidation is indicated. A laboratory direct sodium borohydride/hydrogen peroxide fuel cell using a Zn anode is studied at room temperature. Cell voltages of and short-circuit currents of are reported but cell stability is limited to operation. Energy densities and maximum specific capacities of and , respectively, are obtained. A power density of about at a cell voltage of and a current density of is reported but it cannot be sustained for appreciable operation times.