重质化学二氧化锰制备尖晶石锰酸锂

Preparation and Characterization of Spinel LiMn_2O_4 by Densified Chemical Manganese Dioxide

采用重质化学二氧化锰制备尖晶石LiMn2O4。采用X射线衍射、扫描电镜、恒电流充放电等技术对合成产物进行物相、形貌和电化学分析。结果表明:采用重质化学二氧化锰与电解二氧化锰制备的LiMn2O4粉末具有相似的X射线衍射结果。采用重质化学二氧化锰制备的LiMn2O4在0.2C、0.5C、1C、2C及3C放电倍率下放电比容量分别为108.5、104.7、97.3、86.5mA·h/g和70.7mA·h/g,以电解二氧化锰为原料制备的LiMn2O4放电比容量则分别为106.1、103.4、99.1、89.2mA·h/g和75.5mA·h/g。两种原料制备的LiMn2O4在不同倍率下的比容量和充放电循环性能差别不大,采用重质化学二氧化锰制备的锰酸锂电化学性质可以达到或超过采用电解二氧化锰制备的锰酸锂。

Spinel LiMn2O4 was synthesized from densified chemical manganese dioxide and electrolytic manganese dioxide. The phase identification, surface morphology and electrochemical properties of the synthesized powders were characterized by means of X-ray diffraction, scanning electron microscopy, cyclic vohammetry and galvanostatie charge-discharge experiments. The LiMn2O4 powders prepared from densified chemical manganese dioxide and electrolytic MnO2 show similar X-ray diffraction patterns. When discharged at the rates of 0. 2 C,0. 5 C, 1 C,2 C and 3 C, the capacity of LiMn2O4 powders prepared from densified chemical manganese dioxide is 108.5 mA · h/g, 104.7 mA · h/g, 97.3 mA· h/g, 86.5 mA· h/g and 70. 7 mA · h/g, respectively, while the one prepared from electrolytic MnO2 is 106. 1 mA · k/g,103.4 mA ·h/g,99.1 mA · h/g,89.2 mA· h/g and 75.5 mA · h/g. There is no obvious difference in the cycling behavior between the LiMn2O4 prepared from densified chemical manganese dioxide and the one from electrolytic MnO2. The electrochemical performance of LiMn2O4 prepared from densified chemical manganese dioxide is as good as or even better than that of the one prepared from electrolytic MnO2.