New nanoparticles of (Sm,Zn)-codoped spinel ferrite as negative electrode in Ni/MH batteries with long-term and enhanced electrochemical performance

Abstract In this investigation, the longevity performance of the electrochemical hydrogen storage characteristics, the kinetic properties and the structural characterization of the Sm 0.6 Zn 0.4 Fe 2 O 4 compound were all studied. The Sm0.6Zn0.4Fe2O4 nanomaterial was prepared using sol-gel process. The structural study of the alloy through X-ray diffraction proved the good crystallization of this compound. The electrochemical performance of the Sm0.6Zn0.4Fe2O4 electrode at C/10 rate and at ambient temperature was studied by various electrochemical techniques, such as chronopotentiometry, chronoamperometry and cyclic voltammetry. This compound showed a good electrochemical behaviour with a high capacity (142 mA h.g-1) as well as a good discharge capacity preservation of 64.7% over 100 cycles. There was adequate agreement between the evolution of the different electrochemical parameters (exchange current density, Nernst potential, DH/a 2 ratio and the electrochemical discharge capacity) versus cycle number.