(湘潭大學(xué) 化學(xué)學(xué)院 環(huán)境友好化學(xué)與應(yīng)用教育部重點(diǎn)實(shí)驗(yàn)室，
電化學(xué)能源儲(chǔ)存與轉(zhuǎn)換湖南省重點(diǎn)實(shí)驗(yàn)室，湘潭 411105)
摘 要: 為了提高球形Li1.13[Ni0.5Mn0.5]0.87O2正極材料的電化學(xué)性能，通過(guò)非均勻成核法在材料顆粒表面包覆一層納米CuO；采用XRD、SEM、TEM和充放電測(cè)試儀對(duì)所包覆材料進(jìn)行測(cè)試與表征。結(jié)果表明：適量的CuO包覆可有效地提高Li1.13[Ni0.5Mn0.5]0.87O2正極材料的電化學(xué)性能；當(dāng)CuO包覆量為2%(質(zhì)量分?jǐn)?shù))時(shí)，材料的電化學(xué)性能最佳。在0.1C、2.0~4.6 V充放電條件下，其首次放電容量為213.7 mA？h/g，首次庫(kù)侖效率可達(dá)86.9%。此外，該材料在0.5C倍率下循環(huán)100次后其放電比容量仍為169.5 mA？h/g，容量保持率為79.3%；而未經(jīng)包覆的Li1.13[Ni0.5Mn0.5]0.87O2在相同循環(huán)條件下，容量保持率僅為65.5%。
關(guān)鍵字: 鋰離子電池；富鋰正極材料；氧化銅表面包覆；電化學(xué)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
