Research On The Electrochemical Properties Of La-Mg-Ni System Hydrogen Storage Alloy Electrodes At High Temperature

The basic overview and present application status,especially in MH-Ni battery,of hydrogen storage alloy was comprehensively introduced above all,and there was a brief summarization of study on temperature characteristics of hydrogen storage alloy electrodes in the first part of this paper.The AB_3-3.5type La-Mg-Ni system La_0.65Mg_0.35Ni_x(x=3.0-3.5) hydrogen storage alloys were prepared by induction melting.First,the effect of different B/A ratio on electrochemical properties of La_0.65Mg_0.35Ni_x(x=3.0-3.5)hydrogen storage alloys at high temperature (333K)was investigated;Second,the effect of annealing treatment (1173K)on the electrochemical properties of La_0.65Mg_0.35Ni_x(x=3.0-3.5) hydrogen storage alloys at 333K was studied;Third,the La_0.65Mg_0.35Ni_3.1-xMn_x(x=0.0-0.4)hydrogen storage alloys were prepared by induction melting,and the effect of the different Mn content in the alloys on the electrochemical properties of La_0.65Mg_0.35Ni_3.1-xMn_x(x= 0.0-0.4)hydrogen storage alloys at 333K was investigated.The electrochemical studies show that the low B/A ratio is favorable to improve the discharge performances of hydrogen storage alloy electrodes at high temperature because of their better plateau characteristics for hydrogen absorption,desorption and anti-corrosion properties of electrode alloys when compared to the alloys with high B/A ratio.The high temperature discharge performance of alloy electrodes after annealing treatment at 1173K and Mn substitution for Ni is improved. The P-C isotherms curves show that the plateau pressure and the hysteresis of the hydrogen absorption and desorption decreases obviously with an increase in Mn content.Partialy Mn substitution for Ni also improves the anti-corrosion properties of the alloys.