Effect Of Element Substitution For Vandium On Structure And Electrochemical Characteristices Of Ti-Zr-V-Mn-Ni Solid Solution Alloy

Based on the review of the research and development of the V-based solid solutionhydrogen storage alloys, Ti0.26Zr0.07V0.24Mn0.1Ni0.33hydrogen storage alloy is selected asthe study object of this work. The influence of part rare earth elements and Co elementsubstitution on electrochemical and dynamic properties have been investigatedsystematicalloy.The alloy samples are prepared by the non-selfconsumable vacuum arcmelting. Themicrostructure of the alloys has been investigated by XRD and SEM-EDS. Theelectrochemical and kinetic properties of the alloys，such as discharge capacity, activationperformance and charge retention ability have been investigated. EIS and potentiostaticdischarge technique are also used to analyze hydrogen absorption and desorption kinetics.The results show that the two phases are not changed by the element substitution oflight rare earth La, Ce, Pr, Nd, Sm, heavy rare earth Gd, Ho, Er, Yb, Y and Co for V. Thealloys are all composed of V-based solid solution phase with body centered cubic (bcc)structure and a continuous C14Laves phase with hexagonal structure. Cell volumes andlattice parameters of the two phases are both changed by rare earth elements substitution.The activating ability and maximum discharge capacity of the alloy electrodes areimproved with rare earth element substitution. The discharge capacity of the alloyelectrode is sensitive to temperature. High temperature is beneficial to the alloy electrodedischarging. The substitution of most heavy rare earth elements is beneficial to dynamicperformance of the alloy, especialloy Ho elements. Light rare earth elements Ce and Smsubstitution can improve the cycle life of the battery, and have good overallelectrochemical properties. Substitution of Co for V is not conductive to the activationproperies, but cyclic stability and the high-rate ability have been significantly improved.The best substitution ratio of HRD is Ti0.26Zr0.07V0.24-xMn0.1Ni0.33Co0.03alloy. With theincreasing of Co, Capacity retention ratio gradualloy is increased.