Studies on Bare and Mg-doped LiCoO sub(2) as a cathode material for Lithium ion Batteries

In this paper, we report on the preparation of bare and Mg-doped Li(Mg sub(x)Co sub(1-x))O sub(2) (x = 0, 0.03, 0.05) phases by a molten salt method and their electrochemical properties. They were prepared at 800 degree C for 6 h 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 Aa, c similar to 14.05 Aa). Scanning Electron Microscopy (SEM) show hexagonal type morphology at 800 degree C. Powder density was close to 5.02 gcm super(-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 LiCoO sub(2) show main cathodic and anodic redox peaks at similar to 3.9 V and similar to 4.0 V, respectively. Galvanostatic cycling of Li(Mg sub(x)Co sub(1-x))O sub(2) (x = 0, 0.03, 0.05) showed reversible capacity values at the 60 super(th) cycle to be: 147 ( plus or minus 3) mAh g super(-1) (x = 0), 127 ( plus or minus 3) mAh g super(-1) (x = 0.03), and 131 ( plus or minus 3) mAh g super(-1) (x = 0.05) cycled at a current density of 30 mA g super(-1). Capacity retention is also favourable at 98.5%.