合成温度对全梯度正极材料LiNi0.7Co0.15Mn0.15O2的结构和电化学性能影响
Effect of Synthesis Temperature on the Structural and Electrochemical Properties of a Full Concentration Gradient LiNi0.7Co0.15Mn0.15O2 Cathode Material
作者单位E-mail
谭潮溥 中南大学冶金与环境学院, 长沙 410083  
胡国荣 中南大学冶金与环境学院, 长沙 410083  
杜柯 中南大学冶金与环境学院, 长沙 410083 csutcp@163.com 
骆宏钧 广州锂宝新材料有限公司, 广州 510800  
黄殿华 广州锂宝新材料有限公司, 广州 510800  
段建国 中南大学冶金与环境学院, 长沙 410083  
曹雁冰 中南大学冶金与环境学院, 长沙 410083  
摘要: 通过控制结晶法和浓度梯度进料的方式制备了Ni、Co和Mn三元素组分含量呈全梯度分布的类球形Ni0.7Co0.15Mn0.15(OH)2前驱体,与LiOH·H2O均匀混合并焙烧后获得LiNi0.7Co0.15Mn0.15O2正极材料,系统研究了不同焙烧温度对材料Ni、Co和Mn三元素扩散情况、晶体结构及电化学性能的影响规律。通过能谱仪(EDXS)分析不同焙烧温度下材料颗粒中Ni、Co、Mn三元素的扩散程度。研究结果表明,在800℃下焙烧得到的正极材料梯度分布特征明显且电化学性能最佳,首次放电比容量为186.1 mAh·g-1(2.8~4.3 V,0.2C),2C大倍率充放电条件下循环200次后容量保持率为90.1%。这种材料兼具高比容量及良好的循环稳定性,可以用作下一代高能量密度锂离子电池正极材料。
关键词: 锂离子电池  正极材料  全梯度  元素扩散
基金项目: 国家自然科学基金(No.51602352)资助项目。
Abstract: Spherical Ni0.7Co0.15Mn0.15(OH)2 precursor with a full concentration gradient (FCG) of Ni, Co and Mn elements was obtained via co-precipitation method. The precursor was evenly mixed with LiOH·H2O and then sintered at 750~900℃ for 12 h in oxygen to synthesize FCG-LiNi0.7Co0.15Mn0.15O2 cathode material with the Ni rich in core and Mn rich in the outer layer. The diffusion of Ni, Co, and Mn under different calcination temperatures led to various elements homogeneity, and was analyzed by energy-dispersive X-ray spectroscopy (EDXS). Then, the electrochemical properties of samples were investigated by the charge-discharge test and electrochemical impedance spectroscopy (EIS) test. The results indicate that the cathode material sintered at 800℃ has an obvious concentration-gradient distribution with a shell of LiNi0.52Co0.24Mn0.24O2 and exhibits the optimal electrochemical performance. Under the voltage range 2.8~4.3 V, it deliveres an initial discharge of 186.1 mAh·g-1 at a charge-discharge rate of 0.2C, and shows an excellent capacity retention of 90.1% after 200 cycles at a high rate of 2C.
Keywords: Lithium-ion battery  cathode material  full concentration-gradient  element diffusion
投稿时间:2017-06-19 修订日期:2017-07-26
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谭潮溥,胡国荣,杜柯,骆宏钧,黄殿华,段建国,曹雁冰.合成温度对全梯度正极材料LiNi0.7Co0.15Mn0.15O2的结构和电化学性能影响[J].无机化学学报,2017,33(9):1537-1546.
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