物理化学学报 >> 2021, Vol. 37 >> Issue (11): 2011007.doi: 10.3866/PKU.WHXB202011007

所属专题: 能源与材料化学

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表面限域掺杂提升高比能正极材料稳定性

张思东1,2, 刘园1,3, 祁慕尧1,2, 曹安民1,2,*()   

  1. 1 中国科学院化学研究所,分子纳米结构与纳米技术院重点实验室,北京分子科学国家中心,北京 100190
    2 中国科学院大学,北京 100049
    3 郑州大学基础医学院纳米酶医学中心,郑州 450001
  • 收稿日期:2020-11-02 录用日期:2020-11-27 发布日期:2020-12-03
  • 通讯作者: 曹安民 E-mail:anmin_cao@iccas.ac.cn
  • 作者简介:曹安民,中国科学院化学研究所研究员,1978年出生。2006年博士毕业于中国科学院化学研究所。2007–2012年分别在美国匹兹堡大学、美国德州大学奥斯汀分校从事科研工作。2012年加入中国科学院化学研究所,主要研究方向为功能纳米材料表界面结构的精确调控及其在与能源相关领域中的应用、新型二次电池电极材料体系的开发与应用
  • 基金资助:
    中国科学院前沿科学研究计划(ZDBS-LY-SLH020);北京分子科学国家实验室(BNLMS-CXXM-202010);国家自然科学基金(22025507);国家自然科学基金(21931012);高能量密度硅基动力电池的研发与产业化创新团队(2018607219003)

Localized Surface Doping for Improved Stability of High Energy Cathode Materials

Sidong Zhang1,2, Yuan Liu1,3, Muyao Qi1,2, Anmin Cao1,2,*()   

  1. 1 CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing 100190, China
    2 University of Chinese Academy of Sciences, Beijing 100049, China
    3 Nanozyme Medical Center, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
  • Received:2020-11-02 Accepted:2020-11-27 Published:2020-12-03
  • Contact: Anmin Cao E-mail:anmin_cao@iccas.ac.cn
  • About author:Anmin Cao, Email: anmin_cao@iccas.ac.cn
  • Supported by:
    the Key Research Program of Frontier Sciences, CAS(ZDBS-LY-SLH020);the Beijing National Laboratory for Molecular Sciences(BNLMS-CXXM-202010);the National Natural Science Foundation of China(22025507);the National Natural Science Foundation of China(21931012);the Innovation Team for R&D and industrialization of High Energy Density Si-based Power Batteries(2018607219003)

摘要:

锂离子电池在便携式电子设备、电动汽车等领域得到了广泛应用,随着对电池能量密度需求的日益增加,高比能、高稳定正极材料的开发成为相关研究的重点和难点。而正极材料比能量的提升又同时伴随着其自身结构稳定性和循环稳定性的挑战,使得锂离子电池的稳定性、安全性成为制约其应用的关键挑战。本文以高比能正极材料为研究对象,对影响正极材料结构稳定性、电化学稳定性等一系列因素进行介绍和分析,再从目前改善材料结构稳定性的有效策略入手,对表面限域掺杂这一特殊稳定策略的实现途径、稳定机制进行了总结和分析,并结合现有不同表面修饰方法进行分析和评述,对高比能正极稳定性提升的可能策略及方向进行了展望。

关键词: 锂离子电池, 高比能正极材料, 表面限域掺杂, 均匀包覆, 稳定性

Abstract:

Lithium ion batteries (LIBs) have broad applications in a wide variety of a fields pertaining to energy storage devices. In line with the increasing demand in emerging areas such as long-range electric vehicles and smart grids, there is a continuous effort to achieve high energy by maximizing the reversible capacity of electrode materials, particularly cathode materials. However, in recent years, with the continuous enhancement of battery energy density, safety issues have increasingly attracted the attention of researchers, becoming a non-negligible factor in determining whether the electric vehicle industry has a foothold. The key issue in the development of battery systems with high specific energies is the intrinsic instability of the cathode, with the accompanying question of safety. The failure mechanism and stability of high-specific-capacity cathode materials for the next generation of LIBs, including nickel-rich cathodes, high-voltage spinel cathodes, and lithium-rich layered cathodes, have attracted extensive research attention. Systematic studies related to the intrinsic physical and chemical properties of different cathodes are crucial to elucidate the instability mechanisms of positive active materials. Factors that these studies must address include the stability under extended electrochemical cycles with respect to dissolution of metal ions in LiPF6-based electrolytes due to HF corrosion of the electrode; cation mixing due to the similarity in radius between Li+ and Ni2+; oxygen evolution when the cathode is charged to a high voltage; the origin of cracks generated during repeated charge/discharge processes arising from the anisotropy of the cell parameters; and electrolyte decomposition when traces of water are present. Regulating the surface nanostructure and bulk crystal lattice of electrode materials is an effective way to meet the demand for cathode materials with high energy density and outstanding stability. Surface modification treatment of positive active materials can slow side reactions and the loss of active material, thereby extending the life of the cathode material and improving the safety of the battery. This review is targeted at the failure mechanisms related to the electrochemical cycle, and a synthetic strategy to ameliorate the properties of cathode surface locations, with the electrochemical performance optimized by accurate surface control. From the perspective of the main stability and safety issues of high-energy cathode materials during the electrochemical cycle, a detailed discussion is presented on the current understanding of the mechanism of performance failure. It is crucial to seek out favorable strategies in response to the failures. Considering the surface structure of the cathode in relation to the stability issue, a newly developed protocol, known as surface-localized doping, which can exist in different states to modify the surface properties of high-energy cathodes, is discussed as a means of ensuring significantly improved stability and safety. Finally, we envision the future challenges and possible research directions related to the stability control of next-generation high-energy cathode materials.

Key words: Lithium ion battery, High energy cathode materials, Localized surface doping, Uniform coating, Stability

MSC2000: 

  • O646