Effects of multi-dopants (Zn and Ho) in stabilizing spinel structure for cathode materials in lithium rechargeable batteries—Novel chelated sol–gel synthesis

•Multi-doped pristine spinels used as cathode materials were synthesized via sol–gel method.•The synthesized samples exhibited high degrees of crystallinity and good phase purity.•LiZn0.10Ho0.10Mn1.80O4 was an appropriate candidate for use in lithium-ion rechargeable batteries.

Multi-doped spinels, namely LiMn2O4 and LiZnxHoyMn2−x−yO4 (x = 0.10–0.18; y = 0.02–0.10), for use as cathode materials for lithium-ion rechargeable batteries were synthesized via sol–gel method, using lauric acid as the chelating agent, to obtain micron-sized particles. The physical properties of the synthesized samples were investigated using differential thermal analysis, Fourier-transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy, energy-dispersive X-ray analysis, and electrochemical methods. XRD showed that LiMn2O4 and LiZnxHoyMn2−x−yO4 have high degrees of crystallinity and good phase purities. The SEM images of LiMn2O4 showed an ice-cube morphology with particles of size 1 μm. Charge–discharge studies showed that undoped LiMn2O4 delivered the discharge capacity of 124 mA h/g with coulombic efficiency of 95% during the first cycle, whereas doped spinels delivered discharge capacities of 125, 120, and 127 mA h/g in the first cycle with coulombic efficiencies of 96%, 91%, and 91%, respectively.

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