Comparative Study on the Structure and Electrochemical Properties of RE(Ni,Co,Mn,Ti)5 (RE=La,Ce,Pr,d) Alloys

As main composition of mishmetals, the four pure light lanthanide elements La, Ce,Pr or Nd was used individually instead of Ml or Mm as RE in preparation of AB₅ typed hydrogen storage alloy RE(Ni,Co,Mn,Ti)₅. The four alloys, La(Ni,Co₅Mn,Ti)₅, Ce(Ni,Co>ln,Ti)₅, Pr(Ni,Co,Mn,Ti)₅ and Nd(Ni,Co,Mn,Ti)₅ were then tested, characterized and compared in the their cell volumes (V_cell), P-C-T curves, and mainly electrochemical characteristics against charge/discharge cycles, including the activation cycle number (n_a),the maximum discharge opacity at 50 mA/g charge/discharge rate (C_50,max), the high-rate-dischargeability and the rate of decay (-dC/dn). These properties are compared and analyzed to reveal the difference of the effects of each element on the electrochemical properties of rare earth based AB₅ typed hydrogen storage alloy.