(498b) Novel Chemical Mixtures to Generate Hydrogen for Portable Fuel Cells

Hydrogen fuel cells promise higher power density and double conversion efficiency as compared to DMFCs. Hydrogen storage, however, is a limiting factor in the development of fuel cell power sources. Chemical methods for hydrogen generation are especially interesting for portable applications. In this context, hydrolysis of sodium borohydride (NaBH4) has been extensively studied. Hydrogen yield in this system, however, is limited to 4-5 wt% for practical aqueous solutions and reaction initiation requires introducing a catalyst to the mixture, which is difficult particularly for small scale applications. These limitations are overcome in combustion-based approach to hydrogen generation. In this paper, novel combustible mixtures based on sodium borohydride are investigated. NaBH4/metal/water mixtures with polyacrylamide and NaOH additives demonstrate stable self-sustained combustion and hydrogen yield ~7 wt%. This method can be used to develop portable fuel cell power systems with high specific energy, high power density, no catalyst, simple design (no liquid fuel flow) and safe reaction byproducts.