Effects of addition of manganese and LmNi4.1Al0.25Mn0.3Co0.65 alloy on electrochemical characteristics of Ti0.32Cr0.43−xMnxV0.25 (x = 0-0.08) alloys as anode materials for nickel-metal-hydride batteries

This study examines the effects of the addition of Mn and LmNi4.1Al0.25Mn0.3Co0.65 (Lm: lanthanum-rich mischmetal) alloy on the electrochemical characteristics of body centered cubic (BCC) type Ti0.32Cr0.43−xMnxV0.25 (x = 0-0.08) alloys as negative electrode (anode) materials for nickel-metal-hydride (Ni-MH) batteries. The activation behaviour and discharge capacity of the BCC alloys are improved significantly by ball-milling with LmNi4.1Al0.25Mn0.3Co0.65 alloy because this AB5 alloy acts as a path for hydrogen on the surface of the BCC alloy. Among the Mn-substituted alloys, a Ti0.32Cr0.38Mn0.05V0.25 alloy ball-milled with the AB5 alloy yields the greatest discharge capacity of 340 mAh g−1. In addition, compared with the alloy without Mn, the Mn-substituted alloys exhibit a lower plateau pressure for hydrogen, a better hydrogen-storage capacity in the pressure-composition isotherms and faster surface activation.