Synthesis and electrochemical characterizations of nano-scaled Zn doped LiMn2O4 cathode materials for rechargeable lithium batteries

The LiZnxMn2−xO4 (x = 0.00–0.15) cathode materials for rechargeable lithium-ion batteries were synthesized by simple sol–gel technique using aqueous solutions of metal nitrates and succinic acid as the chelating agent. The gel precursors of metal succinates were dried in vacuum oven for 10 h at 120 °C. After drying, the gel precursors were ground and heated at 900 °C. The structural characterization was carried out by X-ray powder diffraction and X-ray photoelectron spectroscopy to identify the valance state of Mn in the synthesized materials. The sample exhibited a well-defined spinel structure and the lattice parameter was linearly increased with increasing the Zn contents in LiZnxMn2−xO4. Surface morphology and particle size of the synthesized materials were determined by scanning electron microscopy and transmission electron microscopy, respectively. Electrochemical properties were characterized for the assembled Li/LiZnxMn2−xO4 coin type cells using galvanostatic charge/discharge studies at 0.5 C rate and cyclic voltammetry technique in the potential range between 2.75 and 4.5 V at a scan rate of 0.1 mV s−1. Among them Zn doped spinel LiZn0.10Mn1.90O4 has improved the structural stability, high reversible capacity and excellent electrochemical performance of rechargeable lithium batteries.