高等学校化学学报 ›› 2018, Vol. 39 ›› Issue (1): 148.doi: 10.7503/cjcu20170198

• 物理化学 • 上一篇    下一篇

锂离子电池浓度梯度正极材料LiNi0.643Co0.055Mn0.302O2的合成与表征

罗熳, 蒋文全(), 韩雪, 郭荣贵, 李涛, 于丽敏   

  1. 北京有色金属研究总院, 北京 100088
  • 收稿日期:2017-03-31 出版日期:2018-01-10 发布日期:2017-12-19
  • 作者简介:联系人简介: 蒋文全, 男, 教授, 主要从事新能源材料研究. E-mail:jiangwenquan@grinm.com

Synthesis and Characterization of Full Concentration-gradient LiNi0.643Co0.055Mn0.302O2 Cathode Material for Lithium-ion Batteries

LUO Man, JIANG Wenquan*(), HAN Xue, GUO Ronggui, LI Tao, YU Limin   

  1. General Research Institute for Nonferrous Metals, Beijing 100088, China
  • Received:2017-03-31 Online:2018-01-10 Published:2017-12-19
  • Contact: JIANG Wenquan E-mail:jiangwenquan@grinm.com

摘要:

采用“两步”进料方式实现进料口浓度的连续梯度变换, 并根据数学微积分公式完成材料的浓度梯度设计. 通过共沉淀方法和“管道式合成”技术合成了浓度梯度前驱体, 并与过量6.5%的LiOH·H2O在氧气气氛下混合煅烧得到浓度梯度正极材料. 浓度梯度正极材料的平均化学成分由ICP-AES测得为LiNi0.643Co0.055Mn0.302O2. SEM照片显示, 浓度梯度LiNi0.643Co0.055Mn0.302O2正极材料呈球状, 粒径大小约 5 μm, 其振实密度为2.029 g/cm3. XRD谱图表明, LiNi0.643Co0.055Mn0.302O2具有良好的α-NaFeO2层状结构; 最小二乘法Rietveld精修得晶格参数a=0.2877(5) nm, c=1.4242(24) nm, V=0.102088(31) nm3. EDS和元素分布图共同验证了浓度梯度正极材料中Ni, Co, Mn的梯度变化. 电化学测试结果表明, LiNi0.643Co0.055Mn0.302O2初始放电容量为187.68 mA·h ·g-1, 库仑效率为84.76%; 1C倍率下充放电循环200周后放电容量为146.45 mA·h ·g-1, 容量保留率为86.90%.

关键词: 共沉淀, 浓度梯度, 锂离子电池, 正极材料

Abstract:

The “two-step” method was adopted to realize the continuous gradient change of feed concentration and the gradient design of final material was derived from mathematical calculus formula. The full concentration-gradient precursor was prepared via co-precipitation method and technique of “Tubular synthesis”. The final lithiated cathode material was obtained by calcination of the mixture of as-obtained full concentration-gradient precursor and 6.5% excess LiOH·H2O in oxygen, whose average chemical compositions was LiNi0.643Co0.055Mn0.302O2 analyzed by inductively coupled plasma-atomic emission spectrometry(ICP-AES). The LiNi0.643Co0.055Mn0.302O2 particle was nearly spherical and had the size of 5 μm in diameter with narrow particle size distribution and its tap-density was approximately 2.029 g/cm3. A well-ordered α-NaFeO2 layer-structured LiNi0.643Co0.055Mn0.302O2 was confirmed by Rietveld refinement of X-ray diffraction(XRD), in which the lattice parameters were a=0.2877(5) nm, c=1.4242(24) nm, V=0.102088(31) nm3, respectively. Energy dispersive spectrometory(EDS) and element mapping results verified that the concentration of Ni, Co and Mn changed gradually inside out of the particle. LiNi0.643Co0.055Mn0.302O2 delivered an initial discharge capacity of 187.68 mA·h ·g-1 and coloumbic efficiency of 84.76%. After cycling at 1C rate for 200 cycles, the discharge capacity and capacity retention of LiNi0.643Co0.055Mn0.302O2 were 146.45 mA·h ·g-1 and 86.90%, respectively.

Key words: Co-precipitation, Full concentration-gradient, Lithium-ion battery, Cathode material

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