正尖晶石LiMn2O4的合成与电化学性能研究

采用高温固相反应原理合成了LiMn2O4锂离子电池正极材料,研究了合成原料中n(Li)/n(Mn)(摩尔比)和合成温度以及掺杂金属钴元素对合成产物性能和结构的影响,恒电流充放电结果麦明LiMn2O4容量为115～120mAh/g,掺杂钴以后容量下降而循环性能改善,XRD测试分析表明合成产物具有正尖晶石结构;通过进一步优化材料的粒度和电极制备时控制导电剂的加入量,确定了提高LiMn2O4的容量、改善材料循环性能的其他因素.以合成产物为阴极材料,MCMB为阳极材料,组装的18650型锂离子电池的容量达到了1250mAh,循环300次后容量保持70%左右.

Study on synthesis and electrochemical performance of the spinel LiMn2O4

The spinel LiMn 2O 4 used as cathode material of Li-ion battery was synthesized by solid state reaction.The n(Li)/n(Mn)(mole ratio)and the synthesizing temperature were studied as well as the effect of doped Co element on the performance and structure of the synthesized product.The results of constant-current charge/discharge show that the capacity of LiMn 2O 4 is from 115 mAh/g to 120 mAh/g.After doping Co,its capacity is decreased while its cyclic performance is improved.The XRD analysis shows that the synthesized product has the spinel structure.The other factors for increasing the capacity of LiMn 2O 4 and improving the cyclic performance were determined by means of optimizing the granularity of the material and controlling the additive amount of conducting reagent when preparing the electrode.The 18650 Li-ion battery assembled with the synthesized product as the cathode metaerial and MCMB as the anode material has the capacity of 1250 mAh and its capacity retention is about 70% after 300 cycles.