Synthesis and electrochemical characterizations of nano size Ce doped LiMn 2O 4 cathode materials for rechargeable lithium batteries

Abstract

LiCe x Mn 2− x O 4 ( x = 0.00–0.10) 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 valence state of Mn and Ce in the synthesized materials. The sample exhibited a well defined spinel structure and the lattice parameter linearly increased with increasing the cerium contents in LiCe x Mn 2− x O 4. Surface morphology and particle size of the synthesized materials were determined by scanning electron microscopy and transmittance electron microscopy respectively. Electrochemical properties were characterized for assembled Li/LiCe x Mn 2− x O 4 coin type cells using galvanostatic charge/discharge studies at 0.5C rate and cyclic voltammetry in the potential range between 2.75 and 4.5 V at a scan rate of 0.1 mV s −1. Among them cerium doped spinel LiCe 0.05Mn 1.90O 4 has improved structural stability, high reversible capacity and excellent electrochemical performance of rechargeable lithium batteries.