通过简易的无焰燃烧法合成了LiMn₂O₄、LiNi_0.08Mn_1.92O₄和LiNi_0.08Cu_0.05Mn_1.87O₄3种正极材料。利用XRD、SEM、恒电流充放电测试等手段对合成材料的结构、形貌和电化学性能进行了表征。结果表明，所制备的3种正极材料均为立方尖晶石结构；Ni-Cu共掺杂提高了LiNi_0.08Cu_0.05Mn_1.87O₄材料的晶体结构稳定性，表现出比LiNi_0.08Mn_1.92O₄和LiMn₂O₄材料较好的倍率性能和循环寿命。在室温和1 C倍率下，LiNi_0.08Cu_0.05Mn_1.87O₄样品的首次比容量为104.7 mA·h/g，循环200次后的容量保持率为81.38%；在较高的倍率5 C循环1 000次后，容量保持率为68.23%；即使在高温55℃和1 C倍率下，仍可获得较高的首次放电比容量，为110.8 mA·h/g，200次循环后的容量保持率为56.23%。CV和EIS测试结果表明，LiNi_0.08Cu_0.05Mn_1.87O₄具有较好的循环可逆性和较小的电荷转移阻抗。

LiMn₂O₄,LiNi_0.08Mn_1.92O₄ and LiNi_0.08Cu_0.05Mn_1.87O₄,three kinds of cathode materials,are synthesized by a facile flameless combustion method.XRD,SEM and galvanostatic charge/discharge test are employed for the characterization and measurement of crystalline structure,morphology and electrochemical properties.Results show that these three as-prepared cathode materials have a cubic spinel structure.Ni-Cu dual-doping enhances the crystal structure stability of LiNi_0.08Cu_0.05Mn_1.87O₄ sample,which hence exhibits better rate performance and cycle life than LiNi_0.08Mn_1.92O₄ and LiMn₂O₄.At a current rate of 1 C and room temperature,LiNi_0.08Cu_0.05Mn_1.87O₄ has a first-discharge specific capacity of 104.7 mAh·g^-1 and a capacity retention rate of 81.38% after 200 cycles.At a current rate of 5 C,its capacity retention rate can remain 68.23% after 1 000 cycles.Even at 55℃ and 1 C rate,LiNi_0.08Cu_0.05Mn_1.87O₄ still delivers a first discharge specific capacity of 110.8 mAh·g^-1 and a capacity retention rate of 56.23% after 200 cycles.CV and EIS tests demonstrate that LiNi_0.08Cu_0.05Mn_1.87O₄ displays better cycling reversibility and smaller charge transfer impedance.

朱金玉(1994-),女,硕士研究生,研究方向为锂离子电池正极材料,649067356@qq.com