运用动态多重扫描速率法,根据四条不同升温速率下的DSC曲线,计算出在空气气氛下动态合成LiMn2O4过程中的动力学参数,据此提出一个优化的LiMn2O4固相合成工艺,采用固相分段焙烧法制备LiMn2O4正极材料,第一段和第二段的温度分别设在600和830℃.用XRD对合成的粉体材料进行了相结构分析;用恒电流充放电仪对LiMn2O4的电化学性能进行测试.结果表明,合成样品具有良好的尖晶石相结构,在充放电循环时初始放电容量达122mAh/g,同时具备良好的容量保持能力.
The synthesis kinetic parameters of spinel LiMn2O4 produced in air were studied
by the non-isothermal multiple scanning method with DSC at the four heating rates. An optimal solid-state synthesis method was then obtained
based on the above investigations. It employed the two-step method to prepare the spinel-phased LiMn2O4: firstly, the well-mixed raw
materials preheated at 600℃ for several hours and subsequently, raised the temperature to 830℃ and fired at this temperature
for a longer time to get the final products. The microstructures of the final LiMn2O4 samples were investigated by X-ray diffraction. The
electrochemical properties of LiMn2O4 as the cathode materials of Li-ion batteries were measured by the constant current charge-discharge
method: an initial capacity of 122mAh/g and relatively high capacity retention were obtained.
参考文献
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