尖晶石型锰酸锂制备及其电化学性能

锰酸锂被认为是取代商品锂离子电池正极材料的LiCoO2候选材料.以二氧化锰、醋酸锰及氢氧化锂为原料,蒸馏水为分散剂,在空气气氛下进行分段烧结,控制烧结温度和时间,制备了锂离子电池正极材料锰酸锂.用X射线衍射仪,电子扫描电镜对产物的结构特征、微观表面形貌和恒流充放电性能进行了表征.结果表明:所制得正极材料为尖晶石型锰酸锂,结晶度高,无杂质相,材料颗粒的粒径均匀,首次放电比容量为117.3 mAh/g(0.5 mA/cm2,2.8~4.4 V,vs.Li+/Li);50次循环后,放电比容量为107.9 mAh/g,不可逆容量损失为9.4 mAh/g,比容量保持率为92.0%.得到了很好的综合电化学性能.

Optimum synthesis of spinel phase LiMn2O4 by rheological phase reaction method

LiMn2O4 cathode material is a promising candidate to replace the commercialized cathode LiCoO2for lithium ion batteries.LiMn2O4 was synthesized in air atmosphere with MnO2,Mn(Ac)2 and LiOH·H2O as raw materials and distilled water as dispersant when various conditions such as the calcination temperature and time were controlled strictly.The products were characterized by X-ray diffraction(XRD),scanning electronic microscopy(SEM) and galvanostatic cycle.The results showed that the prepared material was spinel phase lithium manganate with characters of high crystallinity,no impurity phase and well-distributed size of the particles.The first discharge specific capacities of the LiMn2O4was 117.3 mAh/g(0.5mA/cm2,2.8 ～ 4.4V,vs.Li+/Li).The discharge specific capacities could still retain about 107.9 mAh/gafter 50 cycles,the irreversible loss of the specific capacity was 9.4 mAh/g,and the specific capacity retention was 92.0%.The good electrochemical properties of the prepared material are obtained.