Improvement of hydride characteristics in hydrogen storage La-Ni based alloy

Abe, Hiroshi; Onuki, Shun*; Shinohara, Yoshiaki*; Sutrisna, F.*; Utsumi, Michiaki*; Matsumura, Yoshihito*; Oshima, Takeshi

Recently, Ni-MH batteries with hydrogen storage La-Ni based alloys as negative electrodes are installed many hybrid cars (HV: Hybrid Vehicle). In this study, we investigate the effects of ion irradiation on the electrochemical hydriding rate of the alkaline pretreatment LaNiAl alloy. We also analyzed the chemical compositions at the surface of the irradiated/un-irradiated samples, their crystal structures, and the phases of bulk. The samples were irradiated with K ion at an acceleration energy of 350 keV with a dose of 1 10 cm using the 400 kV ion implanter, at the TIARA, JAEA. X-ray Photoelectron spectra of the samples indicate that composition of oxide layer was varied on irradiated conditions. These results suggest that improvement of initial hydrogen absorption rate for sample surface is caused by formation of conductive oxide layer by ion irradiation.