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Anodic performances of alkali borohydrides on several electrocatalysts such as Ni, Raney Ni, Pd, Pt, Cu, Au have been studied in an effort to develop suitable electrode materials for a borohydride-fueled fuel cell. The open-circuit potentials (OCPs), polarization performances, and hydrogen evolution behaviors were examined in a three-electrode system. The open-circuit potential was found to be dependent on borohydride concentration and also influenced by the electrocatalyst. In concentrated borohydride solutions used in this work, electrode polarizations were less influenced by the fuel concentration. Borohydrides on different electrocatalysts showed different hydrogen evolution behaviors. The relation of hydrogen evolution rate with the anode current was found to change not only with the concentration of borohydride and but also with the electrode material. Comparison of anodic behaviors of borohydride on different electrodes implies that the anodic oxidation of borohydride, as a multi-step process, may take different reaction paths, depending on the electrocatalyst and reaction conditions such as the borohydride concentration. [Copyright &y& Elsevier]

In order to enhance the effect of fluorination treatment (F-treatment) on charge–discharge characteristics of AB2-type Laves phase alloys, three pulverization methods were applied for the F-treated alloys; e.g. hydriding–dehydriding, dry ball-milling and wet ball-milling. As a result, it was found that the F-treated alloy powder obtained by the wet ball-milling had smaller particle size and larger specific surface area than those obtained by the other two methods. The F-treated alloy electrode prepared from the alloy powder obtained by the wet ball-milling showed good initial activation, high-rate dischargeability and relatively high discharge capacity. These results indicate that the wet ball-milling is a very effective pulverization method in enhancing the effect of the F-treatment. [Copyright &y& Elsevier]

Effects of a modified fluorination treatment (F-treatment), ball-milling in a fluoride solution, on structural and electrochemical characteristics of Zr0.9Ti0.1Mn0.6V0.2Co0.1Ni1.1 alloy were investigated. As a result, it was found that the modified F-treatment improved charge–discharge characteristics such as the initial activation property, discharge capacity and high-rate dischargeability of the alloy. It was also found that the modified F-treatment could effectively deposit Ni species on the alloy surface, compared with the conventional F-treatment. These results suggest that the combination of F-treatment and ball-milling is very effective in forming a Ni-rich surface layer with catalytic activity, leading to improved charge–discharge characteristics. [Copyright &y& Elsevier]