Study On Structure And Electrochemical Performance Of The V-Based Solid Solution Alloy

The purpose of this work is to improve electrochemical performance of V-based solid solution alloy. In this paper, compositon optimizing on Ti-Zr-V-Mn alloy has been done, based on deeply analysis on current situation of research on hydrogen storage alloy.The structure, surface morphology and composition of the Ti_0.4Zr_0.1V_1.1Mn_0.5Cr_0.1Ni_x, Ti_0.4Zr_0.1V_1.1Mn_0.5Ni_0.4Cr_x , Ti_0.4Zr_0.1V_xMn_0.5Ni_0.3-Cr_0.1 and Ti_0.4Zr_0.1V_1.1Mn_xNi_0.4Cr_0.2 alloys were investigated by means of XRD and SEM-EDS analyses. It is shown that these alloys all consist of BCC main phase and C14 Laves secondary phase. And the secondary phase precipitates along the grain boundary in the form of a network, which serves as a electrocatalyst and micro-current collector.The Influence of different element content on electrochemical performance of the alloy is also investigated by measuring discharge capacity, charge retention, high-rate dischargeability and capacity retention. Addition of Ni improves electrocatalytical activity of the alloy. At 20°C, the electrochemical performance of the alloy is improved when the Ni content is increased. And the maxium discharge capacity is 398.2mAh/g at x=0.4, the capacity retention S₉₀ is up to 84.3% at x=0.8. Addition of Cr raises cycle life with decreasing maximum discharge capacity owing to the decrease of two voltage plateaus to one voltage plateau on the discharge voltage curve, and the increase in Mn and V leads to the improvements of high-rate dischargeability and charge retention respectively.