The study on the electrochemical performance of mechanically alloyed Mg-Ti-Ni-based ternary and quaternary hydrogen storage electrode alloys

In this paper, ternary Mg50-xTixNi50 (x = 5,10,15) and quaternary Mg35Ti10M 5Ni50 (M = Y,AI,Zr) magnesium-based hydrogen storage electrodes prepared by means of mechanical alloying (MA) were investigated. Through X-ray diffrac tometer (XRD) and scanning electron microscope (SEM) investigation, the pha se structure transformation and morphology of Mg35Ti15Ni50 during MA proces s were examined. The effects of Ti content on discharge capacity, the cycli ng life and high rate dischargeability of the ternary Mg-Ti-Nli electrode a lloys were studied in the discharge tests. It was found that as the Ti cont ent increased the cycling stability of Mg50-xTixNi50 alloys improved but th e discharge capacity and high rate discharge-ability both decreased. The MA quaternary Mg35Ti10M5Ni50 (M = Y,AI,Zr) alloys had significantly longer cy cling life but lower discharge capacity than the ternary alloy Mg35Ti15Ni50 . Surface coating of alloy particles with Ni was also tested for improving the cycling stability of the ternary alloys and found beneficial for cyclin g stability and bad for discharge capacity (C) 2001 International Associati on for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reser ved.