(1. 金瑞新材料科技股份有限公司，長沙410012； 2. 中南大學 化學化工學院，長沙410083； 3. 湖南長遠鋰科有限公司，長沙410205； 4. 長沙礦冶研究院有限責任公司，長沙410012)
摘 要: 以氧化釔溶膠為包覆前驅(qū)物，利用氧化釔和正極材料表面帶電狀態(tài)不同制備氧化釔包覆LiNi0.5Co0.2Mn0.3O2。采用X射線衍射儀(XRD)、掃描電鏡(SEM)、透射電鏡(TEM)及電化學測試等手段對LiNi0.5Co0.2Mn0.3O2包覆前后的物相結(jié)構(gòu)、表面形貌及電化學性能進行研究。結(jié)果表明：氧化釔包覆并未影響LiNi0.5Co0.2Mn0.3O2的晶體結(jié)構(gòu)，氧化釔以顆粒狀分布在正極材料表面，氧化釔包覆層厚度在15~25 nm，氧化釔在正極材料表面分布比較均勻。與未包覆LiNi0.5Co0.2Mn0.3O2相比，氧化釔包覆后，材料在高電壓下的循環(huán)穩(wěn)定性有所提高，最佳包覆量為0.4%。氧化釔包覆有效降低材料在充放電過程中的極化和電荷轉(zhuǎn)移電阻。
關鍵字: 氧化釔；表面包覆；LiNi0.5Co0.2Mn0.3O2；電化學性能
（1. Kingray New Materials Science and Technology Co., Ltd., Changsha 410012, China; 2. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China; 3. Hunan Changyuan LiCo Co., Ltd., Changsha 410205, China; 4. Changsha Research Institute of Mining and Metallurgy Co., Ltd., Changsha 410012, China）
Abstract:Yttrium oxide coated LiNi0.5Co0.2Mn0.3O2 was successfully prepared based on the different surface potentials between the cathode material and yttrium oxide using yttrium oxide sol as coating precursor. The crystal structure, morphology and electrochemical properties of uncoated and yttrium oxide coated LiNi0.5Co0.2Mn0.3O2 were investigated by X-ray diffractometry(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM) and electrochemical measurements. The results indicate that the crystal structure is not affected by yttrium oxide coating, the yttrium oxide particles homogenously distribute on the surface of cathode materials and the thickness of coating layer is 15-25 nm. Comparing with the uncoated LiNi0.5Co0.2Mn0.3O2, the cycle performance of the cathode material improves after yttrium oxide coating and the optimum coating amount is 0.4%. The charge transfer resistance and the polarization are suppressed after coating during the charge-discharge processes.
Key words: yttrium oxide; surface coating; LiNi0.5Co0.2Mn0.3O2; electrochemical performance
