Activation behaviour of mechanically Ni-coated Zr-based Laves phase hydride electrode

A type of composite particle with pure nickel on the surface of Zr-based Laves phase compound was successfully prepared by means of mechanical ball-milling. X-Ray diffraction shows that after milling with 10 wt% nickel from 30 to 60 min, Zr(Cr0.4Ni0.6)(2) maintains its crystalline state. Further scanning electron microscopy and energy dispersive X-ray analysis reveal that some nickel particles were decorated on the surface of Zr(Cr0.4Ni0.6)(2), and in the meantime some fresh surfaces were simultaneously generated. It is found that these fresh surfaces increase the activation behaviour and the discharge capacity of Zr(Cr0.4Ni0.6)(2). While when nickel particles are coated on its surfaces, not only the discharge capacity increase further, but the activation cycles for the electrode are apparently shortened. According to these results, it is believed that the existence of pure nickel on the surface would make Zr(Cr0.4Ni0.6)(2) to be easily activated in alkaline electrolyte. (C) 1997 Elsevier Science S.A.