Electrochemical and Impedance Spectroscopic Properties of Sm and Fe Co‐Doped LiMn ₂ O ₄ Cathode Material

ABSTRACT The Li‐ion battery cathode materials LiMn 2‐ x (Sm x /2 Fe x /2 )O 4 , ( x = 0, 0.02, 0.04, 0.06, and 0.08) were fabricated using the chemical solution method. The powder X‐ray diffraction, along with Rietveld refinement, were employed on the samples and confirmed the structure as cubic spinel. The cyclic voltammograms of the synthesized cathodes exhibited reduced peak potential differences, indicating improved Li‐ion insertion/de‐insertion kinetics. Furthermore, the doped samples demonstrated superior charge‐discharge capacity and enhanced current response compared to pristine LiMn 2 O 4 . The electrochemical‐based impedance analysis was used to understand the electrolyte‐electrode resistances. It is observed that the doped samples with x = 0.02 and 0.08 showed an enhanced electrical conductivity and establishing their superior electrochemical activity. The charge‐discharge characteristics showed an enhanced discharging capacity for x = 0.02 and 0.08, which reiterates their superior electrochemical activity among other samples. The cycling performance over 40 cycles demonstrated superior stability for the x = 0.02 composition.