Abstract
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Mg-based alloys, Mg1.9Cu0.1Niχ (χ = 1.8, 1.9, 2.0, 2.1), were fabricated through high-energy ball milling, and the effects of nickel content on the electrochemical characteristics have been investigated. A high discharge capacity of 490 mAhg-1 was observed for χ = 1.8, compared with 435 mAhg-1 for χ = 2.1. As to capacity degradation, 66.7 % of initial capacity was lost after 15 cycles for χ = 1.8, while only 47.2% for χ = 2.1. Cyclic Voltammograms (CV) indicates that nickel can help maintain redox reaction current and consequently improve the cycle performance. The X-ray mapping analysis indicates that Mg, Ni, and Cu are uniformly distributed in the particles. The O content in the alloy electrodes after 15 cycles decreases with the increase of Ni content in the alloys, suggesting that Ni can efficiently suppress the formation of Mg(OH) 2. The linear polarization curves show that the exchange current density, namely the rate of hydriding/dehydriding, increases from 13 mAg -1 to 133 mAg-1 when the nickel content varies from 1.8 to 2.1. This is also considered as a reason for the observed improved capacity stability. © J. New. Mat. Electrochem. Systems.