NPL associates, a Team STELLAR partner, has developed a novel all-liquid fuel cell with sodium borohydride (NaBH4) as the fuel and hydrogen peroxide (H2O2) or air as the oxidizer. Waste products are water and sodium metaborate, which can be recycled to produce new sodium borohydride either at a central plant (currently feasible) or in the fuel cell itself (currently in development). An optimized version of the test cell generated 36-W at ~ 60ºC, representing one of the highest power density reported to date for a small fuel cell working at sub-100°C. A 500W stack has been developed and is now operational.

HIGHLIGHTS
- The fuel is environmentally safe and non flammable
- The liquid fuel minimizes cooling issues, in comparison to H2/O2 systems
- The theoretical potential of NaBH4/H2O2 fuel cells is 2.23 V, compared to 1.23 V for H2/O2 fuel cells, so fewer cells are needed to construct a stack of reasonable voltage
- NaBH4/H2O2 much less volatile than H2/O2 or gasoline
- No need for heavy structural tanks to store pressurized gasses
- No need to cryogenically store the liquid fuels
- NaBH4/H2O2 is much less toxic to humans than gasoline

More information is available at http://www.avrc.com/presentations/Sodium_Borohydride_Fuel_Cell_AVRC.ppt and http://www.avrc.com/presentations/NPL_AVRC_NCSU_Seminar.ppt

- Jeff Krukin