组成、 结构与表征
(中南大学 冶金科学与工程学院， 长沙 410083)
摘 要: 以MnO2和LiOH·H2O为原料， 采用机械活化与湿化学集成的方法，在水溶液中直接合成了结晶态的尖晶石锂锰氧化物。 当锂含量介于3.78%~4.35%之间时，所得锂锰氧化物为纳米级球形粉末， 以尖晶石结构为主， 含极少量的Mn3O4杂相；在300~800℃温度范围内热处理后， Mn3O4杂相消失，尖晶石结构更趋完善。 所合成的含锂5.80%的高锂样品则以LiMnO2层状结构为主，含少量Mn3O4杂相，其SEM形貌为片状；在300~700℃下热处理8h后， 层状LiMnO2转变成尖晶石LiMn2O4， Mn3O4杂相峰明显减弱并随热处理温度的升高而消失；当温度升高至700~800℃时，开始出现缺锂的Li1-xMn2O4相。结果表明： 该法制备锂锰氧化物可实现锂、 锰、 氧在原子级水平的均匀混合， 所得产物的热稳定性能良好， 其化学计量组成与结构易于调整和控制。
关键字: 尖晶石锂锰氧化物； 机械活化； 湿化学； 合成； 表征
（College of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:A crystal spinel LiMn2O4 was directly synthesized by using MnO2 and LiOH·H2O as raw materials in aqueous solution by the process of wet-chemistry integrated with mechanically activation. The synthesized Li-Mn-O compound with Li content between 3.78%-4.35% is a nano-powerder with mainly spinel structure of LiMn2O4 besides a little impurity Mn3O4 and similar spherical morphology. After being heat treated at 300-800℃ for 8h, a single spinel LiMn2O4 with perfect structure was obtained with the disappearing of Mn3O4 phase. The sample with Li content of 5.80% has a mainly layered structure of LiMnO2 besides some Mn3O4 and lamellar morphology. The layered LiMnO2 can be transformed completely into spinel LiMn2O4 after being heat treated at 300-700℃ and the Mn3O4 phase decreased gradually and disappeared at last, but a little Li1-xMn2O4 was formed above 700℃. The results show that Li, Mn and O can be mixed in atomic level to form spinel LiMn2O4 in the present process. The products synthesized with Li less than 4.35% have a good thermal stability and the chemical composition and phase structure can be easily adjusted and controlled.
Key words: lithium manganese oxide spinel; mechanical activation; wet chemistry; synthesis; characterization
