控制结晶法制备球形锰酸锂的研究

采用控制结晶法制备出球形MnCO3前驱体,经预处理后得到多孔隙球形Mn2O3,与Li2CO3研磨混料,高温煅烧合成了结晶完整的球形尖晶石型LiMn2O4。比较了普通高温固相法与控制结晶法对锰酸锂电化学性能的影响,结果表明,后者制备得到的球形锰酸锂具有更高的可逆容量和更好的循环稳定性能。常温下,普通高温固相法合成的锰酸锂初始放电比容量为129.12mAh/g,100次循环后容量保持率仅77.38%。而准确化学计量的球形锰酸锂初始放电比容量为129.40mAh/g,100次循环后,容量保持率为95.28%;富锂球形锰酸锂首次放电比容量为116.28mAh/g,经150次充放电循环后,放电比容量为112.95mAh/g,容量衰减率为2.86%,平均每个循环仅衰减0.019%。锰酸锂的球形形貌愈完整,其电化学性能亦愈优越。

Studies on controlled crystallization preparation for spinel LiMn2O4

Controlled crystallization method was put forward to synthesize spherical MnCO3.MnCO3 precursor was mixed uniformly with Li2CO3 in agate mortar,followed by calcination at high temperature,and then spherical or sphere-like spinel LiMn2O4 was attained.The electrochemical performances of LiMn2O4 prepared by normal solid-state reaction and controlled crystallization method respectively were compared.It showed that the stoichiometric spherical LiMn2O4 had obviously excellent electrochemical performance,whose initial reversible capacity was 129.40 mAh/g with high capacity retention of 95.28% after 100 cycles,than those synthesized by solid-state reaction,whose initial reversible capacity was 129.12 mAh/g with capacity retention of 77.38% after 100 cycles.Li-riched spherical LiMn2O4 had the initial reversible capacity of 116.28 mAh/g,holding 112.95 mAh/g after 150 cycles,and the capacity fading was just 2.86%,that is to say,only 0.019% capacity fading each cycle.