Abstract
The electrochemical hydrogenation properties of two boron-free crystalline Co powder samples were investigated. They exhibited almost the same maximum discharge capacities with 2-h charging, 415 and 428 mAhg (corresponding to Co H0.91 and Co H0.93) for samples A and B, respectively. The high discharge capacity of Co powder was attributed to hydrogenation of Co and phase transition between the phases of hexagonal close-packed and face centered cubic. © 2006 The Electrochemical Society.