氧化铝包覆量对锰酸锂正极材料电化学性能的影响

Effect on Electrochemical Performance of Different Ratio of Al₂O₃ Coating LiMn₂O₄ Cathode Material

针对锰酸锂正极材料存在循环性能差的问题,以九水硝酸铝(Al(NO3)3·9H2O)和尖晶石锰酸锂(LiMn2O4)为原料,采用溶胶–凝胶法制备氧化铝包覆锰酸锂正极材料,研究氧化铝包覆量(氧化铝与锰酸锂的质量比)对锰酸锂正极材料的结构及其电化学性能的影响。采用XRD和SEM等手段研究合成材料的晶体结构和微观形貌;通过循环充放电测试和循环伏安法等方法研究其电化学性能。XRD和SEM结果表明:氧化铝的包覆并没有改变锰酸锂的晶体结构,只是包覆在锰酸锂的表面。电化学性能测试结果表明,当氧化铝包覆量为1.0%时,材料具有较好的循环性能,1 C条件下,循环200周容量保持率为96.96%,锰酸锂为52.78%。

In order to improve the cycle performance of LiMn2O4 cathode materials, we synthesize Al2O3 coating LiMn2O4 cathode materials by sol-gel method using Al (NO3)3·9H2O and LiMn2O4 as starting materials. Effects on structure and electrochemical performance of Al2O3 coating LiMn2O4 cathode materials at different ratio have been researched. The crystal structure and morphology of mate-rials were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM);And the electrochemical performance was tested by cyclic voltammetry and cycling experiment. XRD and SEM results show that the coating is only on the surface of LiMn2O4 and it does not affect crystal structure of LiMn2O4. Electrochemical tests show that 1% Al2O3coating sample has an excellent electrochemical performance;the capacity retention is 96.96% at 1 C rate after 200 cycles when capacity retention of the uncoated LiMn2O4 is 52.78%.