碳酸锂和四氧化三锰合成锰酸锂的工艺优化研究

Optimization for synthesis process of lithium manganate from lithium carbonate and trimanganese tetroxide

为了提高锰酸锂的性能,用正交实验法优化了碳酸锂和四氧化三锰固相合成尖晶石锰酸锂的工艺,并结合X射线衍射(XRD)、扫描电镜(SEM)、恒电流充放电技术研究了合成工艺对材料结构、形态、比容量和循环性能的影响。固相反应法制备锰酸锂的工艺条件为:600℃预烧6h,750℃反应30h,600℃退火6h。所得锰酸锂在25℃和50℃下初始放电比容量为138mA·h/g和136mA·h/g,10次循环后容量保持率为97.8%,94.9%。

Spinel type lithium manganate was synthesized by a solid phase reaction from the mixture of lithium carbonate and trimanganese tetroxide. In order to improve the performance of lithium manganate, synthesis conditions were optimized by orthogonal experiment, and samples prepared at different conditions were characterized by X - ray diffraction （ XRD）, scanning electron microscope （ SEM）, and constant current charge-discharge cycling test. Influrences of synthesis conditions on the structure, morphology, specific capacity, and cycling performance of the samples were also investigated. Synthesis conditions of lithium manganate by solid phase method were preheating temperature of 600 ℃, preheating time of 6 h, calcination temperature of 750 ℃, calcination time of 30 h, annealing temperature of 600 ℃, and annealing time of 6 h. Materials synthesized under the optimal conditions provided an initial discharge capacity of 138 mA · h/g and 136 mA ·h/g and capacity retention of 97.8% and 94.9% after 10 cycles at 25 ℃ and 50 ℃ respectively.