(1. 中南大學(xué) 冶金與環(huán)境學(xué)院，長(zhǎng)沙 410083；
2. 中信大錳礦業(yè)有限責(zé)任公司，南寧 530028)
摘 要: 將前驅(qū)體Ni0.5Co0.2Mn0.3(OH)2以及前驅(qū)體和碳酸鋰的混合物分別進(jìn)行熱處理，初步探討其在高溫?zé)崽幚磉^程中的結(jié)構(gòu)變化以及熱處理方式對(duì)材料電化學(xué)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(cè)試技術(shù)對(duì)合成材料物理性能和電化學(xué)進(jìn)行測(cè)試和表征。結(jié)果表明：前驅(qū)體在熱處理過程中，其結(jié)構(gòu)經(jīng)歷由Me(OH)2→NiCoOOH→Mn(Ni,Co)2O4的轉(zhuǎn)變過程；而前驅(qū)體與碳酸鋰的混合物則經(jīng)歷由兩相混合物→三元材料+Li2CO3→三元材料的結(jié)構(gòu)轉(zhuǎn)變過程；相比于單一高溫平臺(tái)熱處理而言，采用低高溫雙平臺(tái)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(xué)性能。電化學(xué)測(cè)試結(jié)果表明：在3.0~4.4 V電壓范圍內(nèi)，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(dá)98.9%。
關(guān)鍵字: 鋰離子電池；正極材料；結(jié)構(gòu)變化；電化學(xué)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
