LiCoO2 thin-film cathodes grown by RF sputtering

LiCoO2 thin-films have been grown by RF magnetron sputtering on silicon substrates covered with gold. As-grown films deposited at substrate temperature 500 degreesC were identified by XRD and RS as an HT hexagonal phase. The structure of the films prepared at substrate temperatures <300 degreesC were less well defined. Nevertheless, the films prepared at 200 degreesC have better electrochemical proper-ties than the films prepared at higher temperatures. The determination of the composition of thin-films showed that the composition approaches to the stoichiometric one for discharge power of 60 W irrespective of substrate temperature. In other cases, a slight excess of Li was found. The films have promising properties to be used as cathodes in lithium-ion (Li-ion) batteries. (C) 2002 Elsevier Science B.V. All rights reserved.