Fu Qiu-lian, Jiang Xiao-yu, Chen Wen-zhe
College of Materials Science & Engineering, Fuzhou University, Fuzhou 350002, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2008 Jun;28(6):1222-6.
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.
采用柠檬酸溶胶-凝胶法合成了钴酸锂。通过热重-差示扫描量热法（TG-DSC）研究了LiCoO₂凝胶前驱体的结晶过程，然后在400至800℃下进行煅烧。通过X射线衍射、红外光谱、拉曼光谱和透射电子显微镜对不同温度下形成的LiCoO₂粉末的晶体结构进行了分析。结果表明，LiCoO₂粉末的平均粒径约为20-40nm，随着煅烧温度从400℃变化到700℃而增大，而在800℃时减小。随着煅烧温度从400℃升高到800℃，结构从改性尖晶石转变为层状岩盐结构。在改性尖晶石结构中，Co²⁺离子位于四面体位置，Co³⁺离子位于八面体位置。然而，在层状岩盐结构中，只有Co³⁺离子位于八面体位置。
