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无机材料学报

无机材料学报

• 研究论文 • 上一篇    下一篇

球形LiNi0.5-xCo2xMn0.5-xO2的合成及其电化学性能

朱勇军, 李新海, 王志兴, 杨志, 胡启阳   

  1. 中南大学冶金科学与工程学院, 长沙 410083

  • 收稿日期:2006-09-05 修回日期:2006-11-09 出版日期:2007-09-20 网络出版日期:2007-09-20

Synthesis and Electrochemical Performance of Spherical LiNi0.5-xCo2xMn0.5-x O2

ZHU Yong-Jun, LI Xin-Hai, WANG Zhi-Xing, YANG Zhi, HU Qi-Yang   

  1. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China

  • Received:2006-09-05 Revised:2006-11-09 Published:2007-09-20 Online:2007-09-20

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摘要： 以化学共沉淀法制备的球形Ni0.5-xCo2xMn0.5-xCO3(x=0.075, 0.1, 1/6)为前驱体合成了球形锂离子电池正极材料LiNi0.5-xCo2xMn0.5-xO2(x=0.075, 0.1, 1/6), 研究了钴含量对LiNi0.5-xCo2xMn0.5-xO2的物理性能和电化学性能的影响. SEM研究表明, 球形LiNi0.5-xCo2xMn0.5-xO2由许多一次颗粒构成, 随着钴含量的增加, 产物中一次颗粒增大. XRD分析表明, LiNi0.5-xCo2xMn0.5-xO2 均为具有层状结构的纯相物质. 电化学性能测试结果显示, LiNi0.5-xCo2xMn0.5-xO2随着钴含量的增加, 材料的充放电容量提高, 且循环性能变好: 0.2C倍率下、2.7～4.3V的电压范围内, LiNi0.425Co0.15Mn0.425O2的放电比容量为145mAh·g-1、LiNi0.4Co0.2Mn0.4O2为150mAh·g-1、LiNi1/3Co1/3Mn1/ 3O2为158mAh·g-1, 循环50周期后LiNi0.425Co0.15Mn0.425O2和LiNi0.4Co0.2Mn0.4O2的容量衰减率在3％以内, LiNi1/3Co1/3Mn1/3O2容量无衰减. 交流阻抗测试结果表明, 随着钴含量的增加, 材料阻抗值减小.

关键词: 锂离子电池, 正极材料, 球形, LiNi0.5-xCo2xMn0.5-xO2

Abstract: Spherical LiNi0.5-xCo2xMn0.5-xO2(x=0.075, 0.1, 1/6) powders were synthesized from the co-precipitated carbonate precursor, Ni0.5-xCo2xMn0.5-xCO3(x=0.075, 0.1, 1/6). The effects of the Co content on the physics and electrochemical performance of LiNi0.5-xCo2xMn0.5-xO2 were investigated. The SEM images of LiNi0.5-xCo2xMn0.5-xO2 show that the spherical material consists of many primary particles, which sizes increase with the content of Co increasement. The results of X-ray powder diffraction show that all LiNi0.5-xCo2xMn0.5-xO2 are pure phase materials with layered structures. The electrochemical tests indicate that the discharge capacities of LiNi0.5-xCo2xMn0.5-xO2 increase and the cycle performances become better with the content of Co increasing. Under the charge/discharge conditions of 0.2C rate and voltage range of 2.7--4.3V, the discharge properties of spherical LiNi0.425Co0.15Mn0.425O2, LiNi0.4Co0.2Mn0.4O2 and LiNi1/3Co1/3Mn1/3O2 are 145,150 and 158 mAh·g-1, respectively. The discharge capacity fadings for LiNi0.425Co0.15Mn0.425O2 and LiNi0.4Co0.2Mn0.4O2 are less than 3％ , however, there is no fade for that of LiNi1/3Co1/3 Mn1/3O2 after 50 cycles. The results of AC impedance show that the impedance decreases with the content of Co increasing.

Key words: Li-ion battery, cathode material, spherical, LiNi0.5-xCo2xMn0.5-xO2

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