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Abstract: Borohydrides are a group of compounds with high hydrogen contents. For example, contains 10.6 wt% hydrogen. The direct anodic oxidation of borohydride provides more negative potentials than that of hydrogen. One ion of generates eight electrons. The theoretical energy density can reach as high as 9.3 Wh/g of NaBH4 if using sodium borohydride as the fuel. The theoretical energy conversion efficiency of the DBFC (0.91) is larger than that of the PEMFC (0.83). Recently, the cell power density 290 mW/cm2 has been achieved. A five-cell stack with an effective area of 67 cm2 demonstrated that the power reached to 110 W when the operation temperature reached 60  C, even if the stack operation started at room temperature without humidification. [Copyright &y& Elsevier]

Abstract: In this study, aqueous borohydride solutions were employed to fuel a micro cell. Electrochemical performance of the micro borohydride fuel cell was tested at ambient conditions without any auxiliary facilities. Electrochemical impedance spectroscopy (EIS) analyses were performed to characterize the cell performance. Both anion and cation exchange membranes were tried to separate the fuel from the cathode. Membrane properties were found to be a decisive factor for cell performance. A maximum power density of 40mW/cm2 at room temperature was achieved when the Nafion NRE211 membrane was used. Hydrogen evolution at the anode side resulted from the competitive hydrolysis reaction influenced cell performance by obstructing transfer of the electrolyte. The cell also demonstrated promising performance even when an Ag cathode was used. [Copyright &y& Elsevier]