Preparation and Mechanism of Li₄Ti₅O₁₂ by Sol-gel Method

Yang Jianwen, Zhong Hui, Zhong Haiyun, Dai Yanyang, Zhao Xuan
(College of Metallurgical Science and Engineering, Central South University, Changsha 410083)

Abstract Spinel Li₄Ti₅O₁₂ was prepared by sol-gel method with citric acid, titanium salt, lithium hydroxide, and the formation mechanism of Li₄Ti₅O₁₂ was studied. According to IR, TGA-DTA , XRD and SEM analysis, the precursors using or without using organic crosslinking agent had similar combinative characters. Citrate could coordinate with Ti(Ⅳ) through a monodentate, and there were [-O-Ti-O-]_n chains in the precursors. In air, thermal decomposition of precursors involved in organic and carbon chains oxidation, and Li₄Ti₅O₁₂ crystal formation and growth. Single phase nanocrystalline Li₄Ti₅O₁₂ were made at 700℃, and ana-TiO₂ intermediate phase was experienced. The Li₄Ti₅O₁₂ powders made at 800℃ were porous and loose aggregates, and fine particle size distribution.
Key words Li₄Ti₅O₁₂, Sol-gel method, Mechanism of formation

Li₄Ti₅O₁₂的溶胶-凝胶法制备及形成机理

杨建文 钟晖 钟海云 戴艳阳 赵绚
(中南大学冶金科学与工程学院 长沙 410083)

摘要 用溶胶-凝胶法合成了纯尖晶石相纳米晶Li₄Ti₅O₁₂，并对其形成机理进行了研究。IF分析表明，水相中与有机交联剂介质中合成的前驱体结构非常相似，柠檬酸根与Ti(Ⅳ)为单齿方式配位，钛与氧形成了[－O－Ti－O－]_n聚合链；TG-DTA和XRD分析表明，前驱体热分解经历了有机物热分解、碳链断裂燃烧与Li₄Ti₅O₁₂形成及晶形成长等阶段；前驱体在热分解的同时就形成了Li₄Ti₅O₁₂，钛元素在反应过程中经历了锐钛矿型-TiO₂中间相，700℃时已成为单一相纳米晶Li₄Ti₅O₁₂；800℃合成粉末的SEM研究表明，产物粒度分布均匀，为球形颗粒的疏松多孔聚集体。
关键词 Li₄Ti₅O₁₂ 溶胶-凝胶法 形成机理

杨建文 男，36岁，博士生，现从事电化学电容器研究。*联系人
2004-02-23收稿，2004-06-20接受

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