尖晶石LiMn_2O_4的低温合成及锂离子嵌脱动力学

Low temperature preparation and kinetics of Li-ion insertion-extraction of spinel LiMn_2O_4

采用前驱体法在400℃下合成了尖晶石LiMn2O4,研究了产物的结晶性能和电化学性能,并对锂离子在样品中的嵌脱动力学进行了研究。结果显示:样品具有很好的结晶性;首次放电比容量为110.3 mAh/g,第20次循环的比容量保持在95.0 mAh/g,容量保持率为86.4%;确定等效电路对实验数据进行拟合,在3.85 V处的电荷传递电阻为24.87Ω,在4.25V处变为14.56Ω,电荷传递电阻随电位的增加先减小后增大。

Spinel LiMn2O4 was synthesized by the precursor method at 400 ℃. The crystallinity and electrochemical performance of the samples were investigated; the kinetics of Li-ion insertion-extraction in the sample was studied. The results showed that the sample had fine crystallinity;its initial discharge specific capacity was 110.3 mAh/g, the specific capacity kept at 95.0 mAh/g at the 20th cycle, the capacity retention was 86.4% ; the equivalent circuit was defined to fitting the experimental data, the charge transfer resistance at 3.85 V was 24.87 Ω, changed to 14.56 Ω at 4.25 V, the charge transfer resistance decreased with the increasing of the potential, then increased.