Cerium and zinc: Dual-doped LiMn2O4 spinels as cathode material for use in lithium rechargeable batteries

Pristine spinel lithium manganese oxide (LiMn₂O₄) and zinc- and cerium-doped lithium manganese oxide [LiZn_xCe_yMn_2−x−yO₄ (x = 0.01–0.10; y = 0.10–0.01)] are synthesized for the first time via the sol–gel route using p-amino benzoic acid as a chelating agent to obtain micron-sized particles and enhanced electrochemical performance. The sol–gel route offers shorter heating time, better homogeneity and control over stoichiometry. The resulting spinel product is characterized through various methods such as thermogravimetic and differential thermal analysis (TG/DTA), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and electrochemical galvanostatic cycling studies. Charge–discharge studies of LiMn₂O₄ samples heated at 850 °C exhibit a discharge capacity of 122 mAh g⁻¹ and a corresponding 99% coulombic efficiency in the 1st cycle. The discharge capacity and cycling performance of LiZn_0.01Ce_0.01Mn_1.98O₄ is found to be superior (124 mAh g⁻¹), with a low capacity fade (0.1 mAh g⁻¹ cycle⁻¹) over the investigated 10 cycles.