Enhanced electrochemical hydrogen storage performance of Ti49Zr26Ni25 alloy by doping with Pd nanoparticles deposited MWCNTs

Mechanical alloying and subsequent annealing are used to fabricate the Ti₄₉Zr₂₆Ni₂₅ quasicrystal. A complexation-reduction method is employed to obtain the Pd deposited multiwall carbon nanotubes (Pd/MWCNTs). Composite of Ti₄₉Zr₂₆Ni₂₅ mixed with Pd/MWCNTs is obtained via ball-milling. The composite alloy combines the characteristics of Pd in conjunction with the advantages of MWCNTs. Pd exhibits outstanding electrocatalytic activity and MWCNTs provide high conductivity and large specific surface area. The electrochemical performance and kinetics properties of the alloy electrodes for Ni/MH secondary batteries are studied. A maximum discharge capacity of 274.6 mAh/g is achieved for Ti₄₉Zr₂₆Ni₂₅ + Pd/MWCNTs, remarkably higher than that for original Ti₄₉Zr₂₆Ni₂₅ (208.9 mAh/g). In addition, the composite shows improved cyclic stability and high-rate dischargeability. The synergistic effect of Pd and MWCNTs can decrease charge-transfer resistance and accelerate the hydrogen transmission, thus improving the reaction kinetics and electrochemical activity of the electrode.