Cathodic Properties of LiCoO2 Synthesized by a Sol-Gel Method for Lithium Ion Battery

摘要

LiCoO2 powder was synthesized in an aqueous solution by a sol-gel method and used as a cathode active material for a lithium ion rechargeable battery. The layered LiCoO2 powders were prepared by igniting in air for 12 hrs at 600 ∩ (600-LiCoO2) and 850 ∩ (850-LiCoO2). The structure of the LiCoO2 powder was assigned to the space group R bar 3 m (lattice parameters a=2.814 ∈ and c=14.04∈). The SEM pictures of 600-LiCoO2 revealed homogeneous and fine particles of about 1 レm in diameter. Cyclic voltammograms (CVs) of 600-LiCoO2 electrode displayed a set of redox peaks at 3.80/4.05 V due to the intercalation/deintercalation of the lithium ions into/out of the LiCoO2 structure. CVs for the 850-LiCoO2 electrode had a major set of redox peaks at 3.88/4.13 V, and two small set of redox peaks at 4.18/4.42 V and 4.05/4.25 V due to phase transitions. The initial charge-discharge capacity was 156-132 mAh/g for the 600-LiCoO2 electrode and 158-131 mAh/g for the 850-LiCoO2 electrode at the current density of 0.2 mA/cm2. The cycleability of the cell consisting of the 600-LiCoO2 electrode was better than that of the 850-LiCoO2. The diffusion coefficient of the Li+ ion in the 600-LiCoO2 electrode was calculated as 4.6】10-8 cm2/sec.