The Electrochemical Characteristics of Mg_2Ni Nanocrystalline Hydrogen Storage Alloy

The nanocrystalline Mg2Ni materials were prepared by mechanical alloying.The cyclic voltammetry results indicated that the potential of oxidation peak was shift as the scan rate increased and the absorption property of Mg2Ni prepared by mechanical alloying was increased even at ambient temperature.The absorption and desorption of hydrogen in Mg2Ni alloy were remarkably accelerated with the rising temperature.Small angel X-ray scattering results indicated that the Mg2Ni powder have 1~5 nm and 5~10 nm particle size distribution,which increased the acting sites of hydrogen absorbtion/desorption reaction and decreased the diffusion path of hydrogen desorption.It was induced to the enhanced performance of Mg2Ni nanocrystalline powder.The cycle life investigated results indicated that the activation property of Mg2Ni nanocrystalline hydrogen storage alloy electrode was execellent,the capacitance maintenance ration was 66% after 200 cycles.The coating of epoxy resin on one side of the electrode had no effect on the activation property and the capacitance maintenance ration was better than the uncoating one.But the anode peak current value and the cathodic peak current value were decreased remarkably which indicated that the hydrogen absorption/desorption rate and the charge/discharge degree had decreased.

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