The electrochemical properties of a single particle of LiCoO2 (8 mu m in diameter) in an organic electrolyte were characterized using a microelectrocle technique, and the high rate capability of commercially available micron-sized LiCoO2 was examined in this study. A Pt microfilament (10 mu m in diameter) was attached to the single LiCoO2 particle in the electrolyte during optical microscope observation, and galvanostatic charge-discharge tests were carried out. The discharge capacity of the single LiCoO2 particle (8 mu m diameter) was 0.157 nA h in the potential range of 3.0-4.2 V vs. Li/Li+, which was close to the theoretical capacity. The discharge rate capability of the single LiCoO2 particle was excellent, and the particle exhibited its full-discharge capacity up to a high rate of 30 C (5 nA). The discharge reaction of the single particle was not controlled by the solid-state diffusion of Li+, but by the charge transfer process at a rate lower than 30 C. The discharge capacity of the particle measured at a high rate of 300 C (50 nA) was 0.12 nAh, which was more than 75% of the full capacity of a single particle. (C) 2008 Elsevier B.V. All rights reserved.