(1. 中南大學 冶金與環(huán)境學院，長沙 410083；
2. 中信大錳礦業(yè)有限責任公司，南寧 530028)
摘 要: 將前驅體Ni0.5Co0.2Mn0.3(OH)2以及前驅體和碳酸鋰的混合物分別進行熱處理，初步探討其在高溫熱處理過程中的結構變化以及熱處理方式對材料電化學性能的影響。采用X射線衍射(XRD)、熱重-差熱分析(TG-DSC)、掃描電鏡(SEM)以及恒流充放電測試技術對合成材料物理性能和電化學進行測試和表征。結果表明：前驅體在熱處理過程中，其結構經歷由Me(OH)2→NiCoOOH→Mn(Ni,Co)2O4的轉變過程；而前驅體與碳酸鋰的混合物則經歷由兩相混合物→三元材料+Li2CO3→三元材料的結構轉變過程；相比于單一高溫平臺熱處理而言，采用低高溫雙平臺熱處理所合成的材料可有效降低陽離子混排，使其具有更好的電化學性能。電化學測試結果表明：在3.0~4.4 V電壓范圍內，其在25 ℃、0.5C下首次放電比容量為160.5 mA？h/g，60次循環(huán)后，容量保持率達98.9%。
關鍵字: 鋰離子電池；正極材料；結構變化；電化學性能
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. Citic Dameng Mining Industries Limited, Nanning 530028, China）
Abstract:The Ni0.5Co0.2Mn0.3(OH)2 precursor and the mixture of Ni0.5Co0.2Mn0.3(OH)2 precursor with Li2CO3 were heat-treated, respectively, during heat-treatment, their structural change and the effects of the heat treatment method were studied. The physical and dectrochemical properties of powders were characaterized by X-ray diffraction, thermogravimetry-differential thermal analysis, scanning electron microscopy and galvanostatic charge-discharge cycling. The structural change of the precursor during the heat-treatments is as follows: Me(OH)2→NiCoOOH→Mn(Ni,Co)2O4. Comparing with single stage heating program, it is proved by the experimental results that the two-stage-heating program can be effectively used to reduce the cation mixing, thus, significantly improve the electrochemical performance of the material. LiNi0.5Co0.2Mn0.3O2 heat-treated by two-stage heating program shows a high initial discharge capacity of 160.5 mA？h/g in the voltage range of 3.0-4.4 V at 25 ℃ and 0.5C, and the capacity retention rate is 98.9% after charge-discharge cycle of 60.
Key words: lithium ion battery; cathode material; structural change; electrochemical performance
