A novel high power density borohydride-air cell

The electrochemistry of an alkaline, aqueous cell based on sodium borohydri de, NaBH4, oxidation has been studied, Cell performance has been elucidated in 3.6 cm(2) laboratory cells constructed with an air cathode and an anode current collector made of highly dispersed gold/platinum particles support ed on high-surface area carbon silk. The number of electrons utilized per m olecule of BH4- oxidized (similar to 6.9 out of a possible 8) implies effic ient utilization of the BH4- oxidation. Specific energies > 180 W h/kg (bas ed on total fuel weight) and power densities > 20 mW/cm(2) at room temperat ure and > 60 mW/cm(2) at 70 degrees C have been obtained. (C) 1999 Elsevier Science S.A. All rights reserved.