Alkaline sodium borohydride gel as a hydrogen source for PEMFC or an energy carrier for NaBH4-air battery

In this preliminary study, we tried to use sodium polyacrylate as the super absorbent polymer to form alkaline NaBH4 gel and explored its possibilities for borohydride hydrolysis and borohydride electro-oxidation. It was found that the absorption capacity of sodium polyacrylate decreased with increasing NaBH4 concentration. The formed gel was rather stable in the sealed vessel but tended to slowly decompose in open air. Hydrogen generation from the gel was carried out using CoCl2 catalyst precursor solutions. Hydrogen generation rate from the alkaline NaBH4 gel was found to be higher and impurities in hydrogen were less than that from the alkaline NaBH4 solution. The NaBH4 gel also successfully powered a NaBH4-air battery.