NiFe2O4@LiMn2O4正极材料的制备及其电化学性能研究

以溶胶-凝胶法制备了不同质量百分比的NiFe₂O₄@LiMn₂O₄复合正极材料。采用X射线衍射、扫描电子显微镜、透射电子显微镜和电化学性能测试等手段, 对NiFe₂O₄@LiMn₂O₄材料的结构、形貌和电化学性能进行表征。结果表明, NiFe₂O₄的包覆并没有改变锰酸锂材料的晶体结构;锰酸锂颗粒表面没有观察到NiFe₂O₄材料存在。当NiFe₂O₄包覆量为1%时, 复合材料具有较好的电化学性能, 其首次充放电效率、循环性能和倍率性能都得到了一定程度的提高, 此时NiFe₂O₄呈薄膜型包覆在锰酸锂颗粒的表面, 厚度约为14 nm, 首次放电比容量(0.1C)为121.2 mAh/g, 10C倍率放电条件下放电比容量为84.8 mAh/g, 1C循环400周后容量保持率为90.64%。

Preparation and Electrochemical Performances of NiFe2O4@LiMn2O4 Cathode Material

NiFe₂O4@LiMn₂O₄ cathode materials with different coating content of lithium-ion batteries were prepared by a sol-gel method. The crystal structure, particle size, surface morphology and electrochemical performance of the cathode material were characterized by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results show that the coating of NiFe₂O₄ does not change the crystal structure, and no NiFe₂O₄ material is observed on the surface of LiMn₂O₄ particles. It is found that the prepared composite material with the coating content of NiFe2O4 at 1% exhibits a good electrochemical performance, and has been improved in terms of initial charge-discharge efficiency, cycle performance and multiplier performance. When a film of NiFe₂O₄ is coated on the LiMn₂O₄ surface, 14 nm in thickness, the initial discharge specific capacity is 121.2 mAH/g at 0.1C and 84.8 mAh/g at 10C, with the capacity retention rate at 90.64% after 400 cycles at 1C rate.