Nd-Mg-Ni alloy electrodes modified by reduced graphene oxide with improved electrochemical kinetics

Abstract

To improve the electrochemical kinetics of Nd-Mg-Ni alloy electrodes, the alloy surface was modified with highly conductive reduced graphene oxide (rGO) via a chemical reduction process. Results indicated that rGO sheets uniformly coated on the alloy surface, yielding a three-dimensional network layer. The coated surfaces contained numerous hydrophilic functional groups, leading to better wettability of the alloy in aqueous alkaline media. This, in turn, increased the concentration of electro-active species at the interface between the electrode and the electrolyte, improving the electrochemical kinetics and the rate discharge of the electrodes. The high rate dischargeability at 1500 mA·g⁻¹ increased from 53.2% to 83.9% after modification. In addition, the modification layer remained stable and introduced a dense metal oxide layer to the alloy surface after a long cycling process. Therefore, the protective layer prevented the discharge capacity from quickly decreasing and improved cycling stability.

Keywords

hydrogen storage alloys / surface modification / graphene oxide / electrochemical properties / kinetics

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