title: [Study on the structure of LiCoO2 synthesized by sol-gel with citric acid].
abstract: Lithium cobalt oxide was synthesized by sol-gel with citric acid. The crystallization process of LiCoO2 gel precursor was studied by TG-DSC, and then it was calcined from 400 to 800 degrees C. The crystal structures of LiCoO2 powders formed at different temperatures were analyzed through X-ray diffraction, Infrared spectrum, Raman spectrum and transmission electron microscope. The results show that the mean grain sizes of LiCoO2 powders are about 20-40 nm, and increase with calcinating temperature changing from 400 to 700 degrees C, while decrease at 800 degrees C. The structure changed from modified spinel to layered-rock-salt with the calcinating temperature from 400 to 800 degrees C. In the modified spinel structure, Co2+ ions reside at the tetrahedral sites and Co3+ ions reside at the octahedral sites. However, in the layered-rock-salt structure, just only Co3+ ions reside at the octahedral sites.
authors.affiliation: College of Materials Science & Engineering, Fuzhou University, Fuzhou 350002, China.
authors.forename: Qiu-lian
authors.initials: QL
authors.lastname: Fu
authors.forename: Xiao-yu
authors.initials: XY
authors.lastname: Jiang
authors.forename: Wen-zhe
authors.initials: WZ
authors.lastname: Chen