高等学校化学学报 ›› 2021, Vol. 42 ›› Issue (5): 1514.doi: 10.7503/cjcu20200489

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高镍三元正极材料的表面包覆策略

王弈艨, 刘凯(), 王保国   

  1. 清华大学化学工程系, 北京 100084
  • 收稿日期:2020-07-23 出版日期:2021-05-10 发布日期:2020-11-27
  • 通讯作者: 刘凯 E-mail:liukai2019@tsinghua.edu.cn
  • 基金资助:
    国家重点研发计划项目(2019YFC0810703);佛山-清华产学研合作协同创新专项(佛山创新专项)资金(2019THFS0128)

Coating Strategies of Ni-rich Layered Cathode in LIBs

WANG Yimeng, LIU Kai(), WANG Baoguo   

  1. Department of Chemical Engineering,Tsinghua University,Beijing 100084,China
  • Received:2020-07-23 Online:2021-05-10 Published:2020-11-27
  • Contact: LIU Kai E-mail:liukai2019@tsinghua.edu.cn
  • Supported by:
    Supported by the National Key Research and Development Program, China(2019YFC0810703);the Tsinghua?Foshan Innovation Special Fund(TFISF), China(2019THFS0128)

摘要:

锂离子电池(LIBs)因具有更高的重量/体积能量密度、 更长的使用寿命、 更低的自放电率等优点而逐渐被广泛应用. 相比于已经广泛使用的钴酸锂和磷酸铁锂等正极材料, 高镍三元正极材料Li[Ni1-x-yCoxMny]O2(NCM)以其高电压和高容量等优点, 逐渐成为下一代高能锂离子电池的首选正极材料之一. 尽管高镍NCM正极材料具有上述优点, 但在进一步的实际应用前还需解决其循环稳定性、 倍率性能和安全性等问题, 这些问题主要源于NCM材料本身的晶体结构不稳定、 正极-电解液间界面副反应及高界面电阻等. 针对这些问题, 目前对高镍NCM正极电化学性能优化的大量研究都与电极-电解液界面有关, 如何通过改善界面稳定性、 增加离子在固液界面的迁移率、 抑制界面副反应、 提高正极材料的稳定性进而改善电池性能成为了关注焦点. 本文总结了目前对于其电化学性能衰减的机理解释, 分类概括了包括电化学惰性包覆锂、 残积物清除剂包覆和锂离子良导体包覆等对于高镍NCM正极材料的颗粒表面包覆策略, 简述了一些新兴的包覆策略, 并对高镍NCM正极材料的发展方向和前景提出了展望.

关键词: 锂离子电池, 高镍三元正极材料, 表面包覆, 固液界面

Abstract:

With the exhaustion of traditional energy resources and the emergence of environmental problems, lithium ion battery has gradually become a widely used energy storage system due to its higher volume/weight energy density, longer service life, lower self-discharge rate and other advantages. Compared with the traditional cathode such as LiCoO2, LiFePO4etc, Nickel-rich layered cathode Li[Ni1-x-yCoxMny]O2(NCM) has become the most preferred cathode materials for due to its advantages of high voltage and high capacity. Although NCM cathode material has the advantages mentioned above, it still faces the problems of cycle stability, rate capability and safety issues before further practical application. These performance deficiencies come from the unstable crystal structure of the NCM material, the side reaction on the positive electrode-electrolyte interface, the high interface resistance and so on. To solve these problems, a lot of work has been done to optimize the electrochemical properties of nickel-rich cathode, which is almost studied around the electrode-electrolyte interface. In this review, we summarized the degradation mechanism of capacity battery performance with NCM cathode, and the optimizing strategy of NCM cathode. And then, main coating strategies including electrochemical inactive coating, li-reactive coating, lithium-ion conductive coating are discussed. On this basis, we summarized the ideas and effects of various surface coating strategies, and finally proposed the prospect about the development of NCM cathode materials.

Key words: Lithium-ion battery, Nickel-rich layered cathode material, Surface coating, Solid-liquid interface

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