Effect Of Doping Oxide And Element Ni On Electrochemical Properties Of Mg₂Ni Hydrogen Storage Alloy

The Mg₂Ni hydrogen storage alloy because of its rich resources,low price,high discharge capacity attractted much attention.However,due to its fragile,easy to corrosion,poor thermodynamic performance and other reasons lead to low electrode discharge capacity and poor cycle stability,limited the large-scale application of Mg₂Ni hydrogen storage alloy.In order to improve the electrochemical performance and reduce the commercial application cost of Mg₂Ni,in the Mg₂Ni alloy doped with metal or non-metallic materials is more common.in this work,metaloxide?Al₂O₃?with pure Ni and rare earth oxide?La₂O₃?were dopped to the Mg₂Ni alloy by experimental method and studied on the structure and performance of alloy,then got many valuable results.Firstly,optimize the preparation process of alloy.Milling the alloy in a vacuum environment and air atmosphere for 6 hours respectively with the ratio of Mg₂Ni to Ni is 9:1.The microstructures and electrochemical properties of the samples were investigated.The results show that the discharge capacity and cycle life of the alloy in the vacuum environment are better than those in the air environment.At the same time,milling the Mg₂Ni and Al₂O₃ in the vacuum environment with/without absolute ethanol and study the electrochemical performance of the sample.The results show that the alloyed sample prepared by adding ethanol in the vacuum environment is the best in the process of milling Mg₂Ni doping catalyst.Secondly,the effect of Al₂O₃ doping amount and milling time on the electrochemical properties of x wt%Al₂O₃-5wt%Ni-Mg₂Ni?x=0?5?10?hydrogen storage alloy electrode was studied.The results show that the maximum discharge capacity of the alloy is the highest when the Al₂O₃ content is 5wt%.When the content is 10wt%,the capacity retention rate is the highest.The sample 10wt%Al₂O₃-5wt%Ni-Mg₂Ni milling for 10h,electrochemical properties is the best.Finally,the composite hydrogen storage alloy was prepared by doping Mg₂Ni with metal oxide?Al₂O₃?and rare earth oxide?La₂O₃?.The effects of different milling time?6h?10h?30h?and content ratio of different components on the electrochemical properties were studied.It is found that,the maximum discharge capacity of the alloy is the best when the La₂O₃ is doped alone,and the cycle life is the best when the alloy is added with 5wt%Al₂O₃.When the the mass ratio of Al₂O₃,La₂O₃ and Mg₂Ni is 0.5:0.5:9,the alloy sample prepared by ball milling for 30 h has the best electrochemical performance.