Research On Electrochemical Hydrogen Storage Performance Of Titanium-based Alloy Composites

In recent years,Ti-based alloys have been widely used as anode materials for Ni-MH batteries due to their good electrochemical hydrogen storage properties in new energy and energy storage materials.In this thesis,Ti₄₉Zr₂₆Ni₂₅ alloy is used as the research object.By doping multi-walled carbon nanotubes（MWCNTs）,mesoporousα-Fe2O3 particles and Cd/Pd core/shell materials,a Ti-based alloy-based composite is formed,and the Ti₄₉Zr₂₆Ni₂₅5 composite is studied.Structure and electrochemical properties of materials.The research contents and results of this thesis are as follows:（1）Ti₄₉Zr₂₆Ni₂₅ quasicrystals were prepared by mechanical alloying technology.Ti₄₉Zr₂₆Ni₂₅5 quasicrystals were prepared by mechanical alloying technology.Ti₄₉Zr₂₆Ni₂₅5 alloy composites doped with wall carbon nanotubes（MWCNTs）were obtained by ball milling,and smaller alloy particles were obtained after doping.Studies have shown that compared with the original Ti₄₉Zr₂₆Ni₂₅5 alloy,the composite has significantly improved discharge capacity,high rate performance,cycle stability,and lower charge transfer resistance.When the amount of MWCNTs was 5 wt.%,The optimal discharge capacity was 254.2 mAh/g,and the capacity retention rate was 63.1%.Due to the lubricating effect and electrocatalytic effect of MWCNTs,the particle size of Ti₄₉Zr₂₆Ni₂₅ alloy is reduced,and the specific surface area is increased,thus providing a fast hydrogen transport channel and improving the electrochemical performance of the alloy.（2）Ti₄₉Zr₂₆Ni₂₅5 quasicrystal alloy was prepared by mechanical alloying method.Mesoporousα-Fe2O3 particles were obtained by a hydrothermal method using chitosan as a template.Ti₄₉Zr₂₆Ni₂₅5 alloy was mixed with different amounts of mesoporousα-Fe₂O₃ to prepare composite materials to enhance the electrochemical performance of Ti₄₉Zr₂₆Ni₂₅.The discharge capacity of the composite is higher than that of the Ti₄₉Zr₂₆Ni₂₅5 alloy,and it reaches the maximum（259.6 mAh/g）with a 5%α-Fe₂O₃additive content.In addition,the alloy composite material exhibits good high rate discharge performance.After doping withα-Fe₂O₃,both the capacity decay rate and charge transfer resistance are reduced,which improves the electrochemical reaction kinetics.The large specific surface area and mesoporous structure ofα-Fe2O3 also facilitate the rapid transport of hydrogen in the alloy,thereby increasing the discharge capacity of the alloy electrode.（3）Cd/Pd core/shell materials were obtained by a two-step reduction method.A Ti₄₉Zr₂₆Ni₂₅+x Cd/Pd（x=3,5 and 7 wt.%）Composite alloy was prepared by ball milling.Studies have shown that for Cd/Pd at 7%addition,a maximum discharge capacity of272.9 mAh/g is achieved,and Ti₄₉Zr₂₆Ni₂₅+5%Cd/Pd shows the best cycle stability.In addition,Ti₄₉Zr₂₆Ni₂₅+Cd/Pd has a higher capacity than Ti₄₉Zr₂₆Ni₂₅+Pd and Ti₄₉Zr₂₆Ni₂₅ alloys,more excellent cycle stability and high rate discharge performance.The unique surface structure of the Ti₄₉Zr₂₆Ni₂₅+Cd/Pd composite material inhibits the dissolution and corrosion of metal substances.The unique core/shell microstructure of Cd/Pd materials further improves the reaction kinetics and electrochemical activity of Ti₄₉Zr₂₆Ni₂₅5 electrode...