A 500-W direct peroxide fuel cell for space power systems

Abstract

The research on a 500-Watt direct sodium-borohydride/hydrogen-peroxide (NaBH 4/H 2O 2) fuel cell is presented here. Aqueous solutions of NaBH 4 and hydrogen peroxide are directly used at the fuel cell anode and cathode, respectively, in place of gaseous reactants. Initial results indicate: 1) conversion efficiency over 60% at a practical current density of 250 m A/cm 2; 2) power density over 0.5 W/cm 2, at 60 degree Celsius. The kiloWatt-stack consists of 24 cells, generating an OCV (open circuit voltage) of ∼ 42V. The design of the reactant manifold overcomes some issues unique to an all-liquid-reactant fuel cell. One such issue is possible short-circuiting of neighboring cells from the conductivity of fuel/oxidant. Another issue is possible excessive corrosion if the manifold is not designed properly. This NaBH 4ZH 2O 2 fuel cell technology is ideal for propulsion/power for aerospace systems such as spacecraft and unmanned aerial vehicles.