Studies on Bare and Mg-doped LiCoO2 as a cathode material for Lithium ion Batteries

In this paper, we report on the preparation of bare and Mg-doped Li(MgxCo1-x)O-2 (x = 0, 0.03, 0.05) phases by a molten salt method and their electrochemical properties. They were prepared at 800 C for 6h in air. Rietveld refined X-Ray Diffraction data of bare (x = 0) and Mg-doped (x = 0.03, 0.05) compounds show a well-ordered hexagonal layer-type structure (a similar to 2.81 angstrom, c similar to 14.05 angstrom). Scanning Electron Microscopy (SEM) show hexagonal type morphology at 800 degrees C. Powder density was close to 5.02 gcm(-3), which compares well with the theoretical value. Electrochemical properties were studied in the voltage range of 2.5-4.3 V vs. Li using Cyclic Voltammetry (CV) and galvanostatic cycling. CV studies on bare and Mg-doped LiCoO2 show main cathodic and anodic redox peaks at similar to 3.9V and similar to 4.0V, respectively. Galvanostatic cycling of Li(MgxCo1-x)O-2 (x = 0, 0.03, 0.05) showed reversible capacity values at the 60th cycle to be: 147 (+/-3) mAh g(-1) (x=0), 127 (+/-3) mAh g(-1) (x=0.03), and 131 (+/-3) mAh g(-1) (x = 0.05) cycled at a current density of 30 mA g(-1). Capacity retention is also favourable at 98.5%. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.