Effect of V addition on activation performances of TiMn1.25Cr0.25 hydrogen storage alloy

Effect of V substitution for partial Mn on activation performances of TiMn1.25Cr0.25 alloy was investigated. It was found that both TiMn1.25Cr0.25 and TiMn0.95V0.3Cr0.25 alloy samples can be activated with easy at moderate activation conditions if without exposure to air before activation. After exposed to air for 30 days, TiMn0.95V0.3Cr0.25 alloy still can be fully activated through five activation cycles. However, there is hardly any hydrogen absorption for TiMn1.25Cr0.25 alloy even after 10 activation cycles. SEM results exhibit that the activation process of TiMn0.95V0.3Cr0.25 and TiMn1.25Cr0.25 alloys is closely related with alloy particle fragmentation. Improved activation characteristics of TiMn0.95V0.3Cr0.25 alloy could be resulted from the decreasing surface oxide layer, changed Ti/Mn ratio on alloy top surface and the increasing lattice parameters.