LiNi_(0.8)Co_(0.15)Al_(0.05)O_2/C复合正极材料的制备及其性能研究  

Preparation and Performance of LiNi_(0.8)Co_(0.15)Al_(0.05)O_2/C Cathode Material

作　　者：许帅军 李军[1] 黄思[1] 李少芳[1] 李雪峰[1] 潘春阳[1] Xu Shuaijun;Li Jun;Huang Si;Li Shaofang;Li Xuefeng;Pan Chunyang(School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China)

机构地区：[1]广东工业大学轻工化工学院,广东广州510006

出　　处：《稀有金属》2017年第12期1333-1338,共6页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(20672023);广东省科技计划项目(2015A050502046)资助

摘　　要：三元正极材料具有优异的电化学性能,但也存在阳离子混排、压实密度不高、充放电效率较低、倍率性能不理想、高温存储和循环性不好等问题。为改善LiNi_(0.8)Co_(0.15)Al_(0.05)O_2的电化学性能,采用固相法制备了碳包覆的LiNi_(0.8)Co_(0.15)Al_(0.05)O_2/C复合材料,并讨论了包覆质量比分别为1.02%,2.01%和2.97%(质量分数)时对材料的结构、形貌和电化学性质的影响。X射线衍射(XRD)和扫描电镜(SEM)测试结果显示:所有样品均为α-NaFeO2六方层状结构,具有类球形形貌。电化学测试结果表明:包覆量为2.01%时材料的综合性能最好,0.1C首次放电比容量达175.5 mAh·g^(-1),未包覆的材料为158.9 mAh·g^(-1),包覆后比纯相LiNi_(0.8)Co_(0.15)Al_(0.05)O_2提高了10.5%;3.0C进行50次循环,容量保持率为88.2%,而未经碳包覆的材料只有75.6%;锂离子的扩散系数由未包覆时的2.05×10^(-13)cm^2·s^(-1)增大到3.76×10^(-12)cm^2·s^(-1),相应的电荷的转移阻抗由79.4Ω减小到53.6Ω。Ternary cathode material was proved to have excellent electrochemical performance. However, this material had some defects such as cation mixing, low compaction density and charge-discharge efficiency, bad rate capability, poor high-temperature storage and cycle performance. LiNi0.8Co0.15Al0.05O2/C cathode material was prepared by solid state reaction methods, which could improve the electrochemical performance of LiNi0.8Co0.15Al0.05O2. Effects of cladding contents including 1.02% , 2.01% and 2.97% （mass fraction） on surface morphologies and electrochemical properties of materials were discussed respectively. Powder X-ray diffraction （PXRD） and scanning electron microscope （SEM） results confirmed that the sample microstructure was α-NaFeO2 phase with spheri- cal morphology. The electrochemical？ testing indicated that 2.01% C-coated sample showed the best electrochemical performance with the first discharge capacity of 175.5 mAh· g- 1 at a charge-discharge rate of 0.1 C, which was 10.5 % higher than the pure phase mate- rial with 158.9 mAh·g-1. And the capacity retention rates of 2.01% C-coated and uncoated material after 50 cycles at 3.0C were 88.2% and 75.6% , respectively. Lithium ion diffusion coefficient increased from 2.05 × 10 -13 to 3.76 × 10 - 12 cm2· s - 1 , and the corresponding charge transfer impedance decreased from 79.4 to 53.6 Ω.

关 键 词：LiNi08Co0115A100502 正极材料 固相法 碳包覆 

分 类 号：TM912.9[电气工程—电力电子与电力传动]