柠檬酸溶胶凝胶法合成LiCoO2的晶体结构研究  

Study on the Structure of LiCoO_2 Synthesized by Sol-Gel with Citric Acid

作　　者：傅秋莲[1] 蒋晓瑜[2] 陈文哲[1] 

机构地区：[1]福州大学材料科学与工程学院,福建福州350002 [2]福建工程学院,福建福州350014

出　　处：《光谱学与光谱分析》2008年第6期1222-1226,共5页Spectroscopy and Spectral Analysis

基　　金：福建省发改委重点工程项目(2006)资助

摘　　要：用柠檬酸为络合剂,采用溶胶凝胶法按照Li^＋∶Co^2＋=1∶1合成锂钴氧化物。利用热分析TG-DSC、X射线衍射、红外光谱、共焦显微Raman光谱和透射电子显微技术分析了锂钴氧化物凝胶体晶化过程及在不同煅烧温度下合成的LiCoO2晶体结构的变化。结果表明：煅烧温度由400℃升高到700℃时,晶体颗粒尺寸增大,其尺寸大小约20-40 nm,但在800℃时有所减小。光谱分析和电子衍射结果表明,随着煅烧温度的升高,LiCoO2晶体结构由改性尖晶石结构转变为层状岩盐结构。在改性尖晶石结构中,二价钴离子占据氧四面体间隙,三价钴离子占据氧八面体间隙;层状结构中,只有三价钴离子占据氧八面体间隙。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 ℃. 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℃, while decrease at 800 ℃. The structure changed from modified spinel to layered-rock-salt with the calcinating temperature from 400 to 800 ℃. In the modified spinel structure, Co^2＋ ions reside at the tetrahedral sites and Co^3＋ ions reside at the octahedral sites. However, in the layered-rock-salt structure, just only Co^3＋ ions reside at the octahedral sites.

关 键 词：钴酸锂 溶胶凝胶法 柠檬酸 晶体结构 

分 类 号：O536[理学—等离子体物理]