Lithium manganese oxide (LiMn 2 O 4 , LMO) is a promising cathode material for Li‐ion batteries owing to its high energy density, low cost, and environmental benignity. However, its practical use is limited by severe capacity fading, primarily caused by the Jahn–Teller distortion associated with Mn 3+ and the dissolution of Mn into the electrolyte. In this study, we explore a multidoping strategy to overcome these drawbacks by synthesizing multicomponent oxides of formula LiCr x Fe y Mn 2− x − y−z Ti z O 4 via a facile sol–gel method. Three compositions with varying transition metal ratios were investigated to evaluate the effects of cationic substitution on electrochemical behavior and structural stability. The best performance was achieved for compositions containing all four transition metals (Cr, Fe, Mn, and Ti). Ex situ and operando X‐ray diffraction and X‐ray absorption spectroscopy revealed excellent structural stability, with no evidence of phase separation or Jahn–Teller‐induced distortion even after 60 cycles. Manganese was identified as the sole electrochemically active element, undergoing a reversible Mn 4+ /Mn 3+ redox process through an intercalation/deintercalation mechanism. These results demonstrate that multidoping effectively enhances the structural and electrochemical stability of spinel‐type cathodes, providing a viable pathway toward the design of Co‐free and Ni‐free electrodes for next‐generation Li‐ion batteries.
Callegari et al. (Tue,) studied this question.