Structure and electrical properties of sputtered lithium cobaltite thin films

Kalya J. Rao (1, 2) , Hanane Benqlilou-Moudden (2) , Gérard Couturier (3) , Philippe Vinatier (2) , Alain Levasseur (2)

1 Solid State and Structural Chemistry Unit, Material Research Center
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
3 CPMOH - Centre de physique moléculaire optique et hertzienne

LixCoOy films with x<1 and y>2 have been prepared by radio-frequency (rf) sputtering from high temperature (HT) LiCoO2 targets. Their structures have been examined with high resolution electron microscopy. Conductivities have been studied between 77 and 400 K. The electrochemical behaviour of film electrodes have been investigated with Li/LiClO4-PC/LixCoOy cells. The annealed films consist of nanocrystalline domains with amorphous boundaries. Electrical conductivities appear to arise from variable-range hopping (VRH) of holes. The films form good electrodes with operating potentials between 2.7 and 3.8 V. The observations have been discussed on the basis of a tentative and heuristic molecular orbital based energy band diagram.

Mots clés: X-ray diffraction; Electrical properties; Microstructure

Domaines: Matériaux

Kalya J. Rao, Hanane Benqlilou-Moudden, Gérard Couturier, Philippe Vinatier, Alain Levasseur. Structure and electrical properties of sputtered lithium cobaltite thin films. Materials Research Bulletin, 2002, 37 (7), pp.1353-1367. ⟨10.1016/S0025-5408(02)00756-0⟩. ⟨hal-00728211⟩