高等学校化学学报 ›› 2018, Vol. 39 ›› Issue (10): 2238-2244.doi: 10.7503/cjcu20180343

• 物理化学 • 上一篇    下一篇

MnO2包覆改性富锂锰基正极材料作用机理的电化学研究

邱家欣, 江奇(), 高艺珂, 彭俊棋, 段志虹, 卢晓英   

  1. 西南交通大学超导与新能源研究开发中心, 生命科学与工程学院,材料先进技术教育部重点实验室, 成都 610031
  • 收稿日期:2018-05-04 出版日期:2018-09-29 发布日期:2018-09-29
  • 作者简介:

    联系人简介: 江 奇, 男, 博士, 教授, 博士生导师, 主要从事纳米材料的制备与应用研究. E-mail: jiangqi66@163.com

  • 基金资助:
    国家自然科学基金(批准号: 50907056, 51602266)、 四川省重点研发计划项目(批准号: 2017GZ0109)、 四川省科技支撑项目(批准号: 2016GZ0273, 2016GZ0275)和四川省学术与技术带头人培养基金资助.

Electrochemical Studies on the Working Mechanism of Lithium-rich Manganese Based Material Coated by MnO2

QIU Jiaxin, JIANG Qi*(), GAO Yike, PENG Junqi, DUAN Zhihong, LU Xiaoying   

  1. Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Life Science and Engineering, Superconductivity and New Energy R&D Centre,Southwest Jiaotong University, Chengdu 610031, China
  • Received:2018-05-04 Online:2018-09-29 Published:2018-09-29
  • Contact: JIANG Qi E-mail:jiangqi66@163.com
  • Supported by:
    † Supported by the National Natural Science Foundation of China(Nos. 50907056, 51602266), the Sichuan Key Research and Development Program, China(No. 2017GZ0109), the Sichuan Science and Technology Support Projects, China(Nos. 2016GZ0273, 2016GZ0275) and the Sichuan Academic and Technical Leaders Training Fund, China.

摘要:

采用固相反应制备了富锂锰基正极材料, 并利用化学沉淀及热处理工艺进行MnO2表面包覆改性. 通过恒流充放电、 循环伏安及交流阻抗谱对所得材料进行电化学性能测试, 通过改性前后电化学反应的变化研究了MnO2对富锂锰基材料包覆改性的作用机理. 研究结果表明, MnO2包覆层能发挥储锂作用. 在热处理过程中, 富锂锰基材料中的锂、 镍元素发生迁移扩散, 在MnO2包覆层中形成新的尖晶石复合相, 并可逆地参与后续循环反应, 这对材料电化学性能的提升具有积极作用.

关键词: 二氧化锰包覆层, 富锂锰基材料, 作用机理

Abstract:

In order to investigate the characteristic reactions and structural changes of lithium-rich manganese based material coated by MnO2, the lithium-rich manganese based material was prepared by solid state reaction, and then modified with MnO2 by chemical precipitation and heat treatment. The electrochemical performances of the obtained materials were characterized by constant current charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy. The working mechanism of lithium-rich manganese based materials coated by MnO2 was studied by discussing the changes of the electrochemical reactions before and after the modification. The results show that the coating MnO2 can work as the container of lithium. During the heat treatment process, lithium and nickel elements of the lithium-rich manganese based material migrate and diffuse into the MnO2 coating to form a new spinel composite phase, which reversibly participates in the subsequent cyclic reactions and makes its contribution to enhance the battery electrochemical performances.

Key words: MnO2 coating, Lithium-rich manganese based material, Working mechanism

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