Abstract
Mechanical alloying of Ti45Zr38Ni17 powder mixture formed an amorphous phase, but subsequent annealing caused the formation of an icosahedral (I) quasicrystal phase with a small amount of the Ti2Ni-type crystal phase, so that two kinds of working electrodes, amorphous and quasicrystal ones, were produced and their electrochemical performances were compared. Discharge capacity of quasicrystal electrode was significantly higher than that of amorphous one at room temperature. In every electrode, however, a few charge/discharge cycles were needed to be activated. After charge/discharge cycles, quasicrystal phase was stable but the amorphous phase turned into a (Ti,Zr)H2 hydride particularly after 20th cycle. At a current density of 15mA/g, discharge capacities of both quasicrystal and amorphous electrodes became higher at charging temperature of 328K than those at room temperature. The maximum capacities for both electrodes at 328 K were obtained in the 1st cycle, different from those at room temperature. It was indicated that quasicrystal electrode had higher discharge capacity and cycle stability than amorphous one.
