Synthesis and electrochemical properties of Ti doped LiCoO2 thin film cathodes

Titanium-doped LiCoO2 thin films were grown by pulsed laser deposition technique on silicon substrates. Structure, morphology were investigated using X-ray diffraction, and atomic force microscopy. The film formation was studied as a function of the preparation conditions, i.e. substrate temperature (T-s) and oxygen partial pressure (pO(2)) in the deposition chamber. The films deposited in pO(2) = 100 mTorr showed good crystallinity on silicon substrates maintained at T-s = 700 degrees C. It was found that such a film crystallizes in the layered alpha-NaFeO2 structure. The influence of Titanium doping on particle size and morphologies has been clearly studied. The electrochemical measurements were carried out on Li//LiTi(y)Co(1-y)O2 cells with lithium metal foil as anode and a LiTiyCo1-yO2 film as cathode of 1.5 cm(2) active area using Teflon home-made cell hardware. Cyclic voltammetry (CV) measurements have been carried out at sweep rate alpha= 1 mVs(-1). The Li//LiTiyCo1-yO2 cell delivered a specific capacity of 225 mC/mu m cm(2). (C) 2009 Elsevier B.V. All rights reserved.