Electrochimica Acta, Vol.51, No.2, 268-273, 2005
As-deposited LiCoO2 thin film cathodes prepared by rf magnetron sputtering
LiCoO2 thin films were deposited using radio frequency (rf) magnetron sputtering system on stainless steel substrates. Different rf powers, up to 150 W, were applied during deposition. The as-deposited films exhibited (10 1) and (10 4) preferred orientation and the nanocrystalline film structure was enhanced with increasing rf power. The film crystallinity was examined using X-ray diffraction, Raman scattering spectroscopy and transmission electron microscopy. The compositions of the films were determined by inductively coupled plasma-mass spectroscopy. The average discharge capacity of as-deposited films is about 59 mu Ah/(cm(2) mu m) for cut-off voltage range of 4.2 and 3.0 V. From the electrochemical cycling data, it is suggested that as-deposited LiCoO2 films with a nanocrystalline structure and a favorable preferred orientation, e.g. (10 1) or (104) texture, can be used without post-annealing at high temperatures for solid-state thin film batteries. (C) 2005 Elsevier Ltd. All rights reserved.