A new electrode material for nickel-metal hydride batteries: MgNi-graphite composites prepared by ball-milling

MgNi-graphite composites prepared by ball-milling were found to show greatly enhanced charge-discharge characteristics with respect to the original MgNi alloy. There was an optimal ball-milling time for the preparation of the MgNi graphite composite with enhanced electrode performance, when the modification with graphite was limited to the surface layer of MgNi alloy. Raman and XPS investigations on the composites indicated a decline in the pi-electron character of graphite and changes in the chemical states of the constituents on alloy surface, suggesting the possibility of charge transfer between graphite and MgNi alloy during ball-milling, which resulted in an increase in the surface Ni/Mg ratio. (C) 1999 Elsevier Science S.A. All rights reserved.