Electrochemical evaluation of dual-doped LiMn2O4 spinels synthesized via co-precipitation method as cathode material for lithium rechargeable batteries

Abstract

LiMn2O4 and LiZnxWyMn2−x−yO4 (x=0.15–0.20; y=0.10–0.05) powders are synthesized via co-precipitation method using terephthalic acid as chelating agent. The synthesized samples have been subjected to physical studies viz., thermo-gravimetric 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), Transmission electron microscopy (TEM) and electrochemical characterization viz., electrochemical galvanostatic cycling studies. Zinc and tungsten doped particles of average 100nm size are present with clear grain boundaries. Charge–discharge studies show the pristine LiMn2O4 delivers the discharge capacity of 121mAhg−1 in the first cycle. Among the investigated dopant concentrations, LiZn0.15W0.10Mn1.75O4 sample delivers superior performance (120mAhg−1) with very low capacity fade of 0.84mAhg−1cycle−1 over the investigated 25 cycles as compared to the undoped and doped spinels and is well accorded with impedance measurements.