(湘潭大学 化学学院 环境友好化学与应用教育部重点实验室，
电化学能源储存与转换湖南省重点实验室，湘潭 411105)
摘 要: 为了提高球形Li1.13[Ni0.5Mn0.5]0.87O2正极材料的电化学性能，通过非均匀成核法在材料颗粒表面包覆一层纳米CuO；采用XRD、SEM、TEM和充放电测试仪对所包覆材料进行测试与表征。结果表明：适量的CuO包覆可有效地提高Li1.13[Ni0.5Mn0.5]0.87O2正极材料的电化学性能；当CuO包覆量为2%(质量分数)时，材料的电化学性能最佳。在0.1C、2.0~4.6 V充放电条件下，其首次放电容量为213.7 mA？h/g，首次库仑效率可达86.9%。此外，该材料在0.5C倍率下循环100次后其放电比容量仍为169.5 mA？h/g，容量保持率为79.3%；而未经包覆的Li1.13[Ni0.5Mn0.5]0.87O2在相同循环条件下，容量保持率仅为65.5%。
关键字: 锂离子电池；富锂正极材料；氧化铜表面包覆；电化学性能
（Key Laboratory of Environmentally Friendly Chemistry and Applications,
Key Laboratory of Electrochemical Energy Storage and Conversion of Hunan Province, Ministry of Education,
School of Chemistry, Xiangtan University, Xiangtan 411105, China）
Abstract:In order to improve the electrochemical performance of spherical Li1.13[Ni0.5Mn0.5]0.87O2 cathode material, CuO-coated Li1.13[Ni0.5Mn0.5]0.87O2 cathode material was synthesized by heterogeneous nucleation process. The physical and electrochemical properties of the pristine and CuO-coated materials were characterized by XRD, SEM, TEM and electrochemical measurements. The results show that the electrochemical properties of the Li1.13[Ni0.5Mn0.5]0.87O2 are significantly improved with proper amount of CuO coating. Especially, the 2% CuO-coated sample exhibits the best electrochemical properties, which delivers a high initial discharge capacity of 213.7 mA？h/g at rate of 0.1C in the voltage range of 2.0-4.6 V with coulombic efficiency of 86.9%. Additionally, the 2% CuO-coated sample shows improved cycling stability with capacity retention of 79.3% after 100 cycles at 0.5C, while only 65.5% for the pristine Li1.13[Ni0.5Mn0.5]0.87O2 under the same charge-discharge condition.
Key words: lithium-ion battery; Li-rich cathode material; copper oxide surface coating; electrochemical performance
