This work study a new material Sm_0.6Zn_0.4Fe₂O₄ used as a negative electrode in nickel-metal hydride batteries, The choice of this material was guided by the fact that it is based on Fe₃O₄ which has proven to be very efficient in lithium-ion battery that's why the present work study their potentiality in nickel-metal hydride batteries. The Sm_0.6Zn_0.4Fe₂O₄ is synthesized by the sol-gel method. X-ray diffraction shows that this compound crystallizes in the cubic system in space group Fd-3m. The electrochemical properties of the Sm_0.6Zn_0.4Fe₂O₄ electrode are studied at room temperature using chronopotentiometry technique.

This study focuses on the structural and electrochemical behavior of the compound ZnLaFeO₄ as a negative electrode material for nickel–metal hydride (Ni-MH) batteries. The material was synthesized by a sol–gel hydrothermal method to assess the influence of lanthanum doping on the ZnFe₂O₄ spinel structure. X-ray diffraction revealed the formation of a dominant LaFeO₃ perovskite phase, with ZnFe₂O₄ and La₂O₃ as secondary phases. SEM analysis showed agglomerated grains with an irregular morphology. Electrochemical characterization at room temperature and a discharge rate of C/10 (full charge in 10 h) revealed a maximum discharge capacity of 106 mAhg⁻¹. Although La³⁺ doping modified the microstructure and slowed the activation process, the electrode exhibited stable cycling with moderate polarization behavior. The decrease in capacity during cycling is due mainly to higher internal resistance. These results highlight the potential and limitations of La-doped spinel ferrites as alternative negative electrodes for Ni-MH systems.