Hydrogen electrode reaction of lithium and sodium aluminum hydrides

Any chemical reagents with reducing power can be theoretically utilized as an active material for fuel cell anode. Until now the electrochemical oxidation of NaBH4NaBH4 dissolved in alkaline aqueous solution has been studied in detail. In our laboratory we are examining another inorganic reducing agent with high energy density that can serve as a fuel. In the last decade alkaline metal aluminum hydride (MAlH4)(MAlH4), a complex hydride, has attracted increasing attention as hydrogen storage material. As an electrochemical application of MAlH4MAlH4, we have investigated the hydrogen electrode reaction of LiAlH4LiAlH4 and NaAlH4NaAlH4 in tetrahydrofuran under Ar atmosphere at room temperature. Cyclic voltammetry indicates the redox reaction of M+/MM+/M around 0 V and the large anodic current with hydrogen gas generation at high potential due to the oxidation of [AlH4]-[AlH4]- anion. We infer that the hydrogen electrode reaction of [AlH4]-[AlH4]- anion is induced by the presence of aluminum hydride.