LiMn2O4的机械活化-湿化学合成机理

以MnO2为锰源，采用机械活化与湿化学集成的方法首次在水溶液中合成了尖晶石锂锰氧化物。研究表明，经机械活化后的MnO2具有较高的反应活性，其在水溶液中与锂化合物反应2h后，产物的嵌锂量达3．94％。其尖晶石锂锰氧化物的形成过程经历了MnO2的预活化和预还原、MnO2的锂化、结构重组与转晶3个步骤，随合成时间的延长，合成产物的化学组成与物相结构趋于稳定，所得合成材料具有完整而稳定的尖晶石结构，并具有良好的热稳定性和充放电循环稳定性，富锂尖晶石Li1.04Mn1.96O4的初始充电容量为122．4mAh／g,初始放电容量为112．0mAh／g．分别达其理论容量的97．4％和89.1％；第2～5次循环的放电容量稳定在111.7～110.7mAh／g之间。

The synthetic mechanism for LiMn2O4 by mechanically activated-wet chemistry method

Spinel LiMn_2O_4 was synthesized for the first time in aqueous solution by wet chemistry integrated with mechanical activation. The results showed that MnO_2 has high reactive activity after mechanically activated and the Li content in the product was up to 3.94wt% after it reacted with Li compounds for 2.0h in aqueous solution. The spinel LiMn_2O_4 were formed through three steps in the process, which were pre-activating and pre-reducing for the MnO_2, lithium inserting into MnO_2 and structure reconstructing and crystal transforming. Both the chemical composition and the phase structure of the material synthesized were getting more stable with the increasing of the reacting time. The LiMn_2O_4 cathode material obtained has perfect spinel structure and superior behaviors, such as better thermal stability and excellent circling performance. The Li-rich spinel Li_(1.04)Mn_(1.96)O_4 has first charge capacity of 122.4mAh/g and first discharge capacity of 112.1mAh/g which were 97.4% and 89.1% of its theoretical capacity, respectively. The discharge capacity was between 111.7 mAh/g and 110.7mAh/g from the second circle to the fifth.