Synthesis and electrochemical property of LiCoO2 thin film coated on the surface of carbon and anatase TiO2 powders

Abstract

For the high rate discharge capability, LiCoO2 with the layered rock salt structure thin films were coated on the surface of carbon materials using the nanosheet restacking method and hydrothermal treatment. LiCoO2 thin films consisted of nano-particles with the size of ca.30nm are synthesized through the electrophorestic deposition of cobalt hydroxide nanosheet precursor on the carbon material and the subsequent hydrothermal treatment. To optimize the synthesis condition, LiCoO2 film without any binders and conductive additives was synthesized on the glassy carbon substrate. An excellent high rate discharge capability, 72% of cathode utilization efficiency at 300C-rate compared with that at 30C-rate, was obtained using the thinnest film with 5min deposition time. In the LiCoO2 coating on the surface of powder supports (Toka Black, Denka Black and anatase TiO2), LiCoO2 coated on Denka Black showed good charge–discharge performance. From the surface observation by SEM, LiCoO2 nano-particles are found to be coated on the surface of Denka Black homogeneously, while LiCoO2 nano-powder was aggregated in the system of Toka Black.LiCoO2 coated on Denka Black showed a good high rate charge–discharge capability: 66% of the capacity retained at 17C in comparison with that at 1.7C, which is superior to the reports of other bulk materials.