SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2023, Vol. 56 ›› Issue (4): 58-69.DOI: 10.1016/j.cjche.2022.06.030

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The feasibility for natural graphite to replace artificial graphite in organic electrolyte with different film-forming additives

Shaojun Niu1,2, Guobin Zhu1, Kai Wu2, Honghe Zheng1   

  1. 1. College of Energy, Soochow University, Suzhou 215006, China;
    2. Contemporary Amperex Technology Limited, Ningde 352100, China
  • Received:2022-01-12 Revised:2022-06-19 Online:2023-06-13 Published:2023-04-28
  • Contact: Guobin Zhu,E-mail:gbzhu@suda.edu.cn;Kai Wu,E-mail:WuK@catl.battery.com;Honghe Zheng,E-mail:hhzheng@suda.edu.cn
  • Supported by:
    This work was financially supported by the National Key Research and Development Program of China (2016YFB0100400) and the National Natural Science Foundation of China (21875154, 22179090).

The feasibility for natural graphite to replace artificial graphite in organic electrolyte with different film-forming additives

Shaojun Niu1,2, Guobin Zhu1, Kai Wu2, Honghe Zheng1   

  1. 1. College of Energy, Soochow University, Suzhou 215006, China;
    2. Contemporary Amperex Technology Limited, Ningde 352100, China
  • 通讯作者: Guobin Zhu,E-mail:gbzhu@suda.edu.cn;Kai Wu,E-mail:WuK@catl.battery.com;Honghe Zheng,E-mail:hhzheng@suda.edu.cn
  • 基金资助:
    This work was financially supported by the National Key Research and Development Program of China (2016YFB0100400) and the National Natural Science Foundation of China (21875154, 22179090).

Abstract: The feasibility for natural graphite (NG) to replace artificial graphite (AG) in organic electrolytes with different additives are investigated. Although the strong film-forming additives contributes to form robust solid electrolyte interphase (SEI) film on graphite particle surface, great differences in gas evolution, lithium inventory loss and other side reactions are observed. Lithium bis(oxalato)borate (LiBOB) and fluoroethylene carbonate (FEC) are found more effective and the combination shows to be more promising. In the optimized electrolyte, natural graphite anode exhibits excellent long-term cycling capability. After 800 cycles at high temperature, the capacity retention is comparable to that using artificial graphite. The mechanisms for the capacity-fading of the full cells with AG and NG anode are investigated by ICP, SEM and polarization studies. The results shows that NG electrode consumes more active lithium due to the rough surface and larger volume expansion. The rapid capacity-fading in the initial 100 cycles is related to the instability of the SEI film aroused from large volume expansion. The systematic analysis is inspiriting for the development of high performance lithium ion batteries with reduced cost.

Key words: Lithium ion batteries, Natural graphite, Electrolyte additive, Solid electrolyte interphase

摘要: The feasibility for natural graphite (NG) to replace artificial graphite (AG) in organic electrolytes with different additives are investigated. Although the strong film-forming additives contributes to form robust solid electrolyte interphase (SEI) film on graphite particle surface, great differences in gas evolution, lithium inventory loss and other side reactions are observed. Lithium bis(oxalato)borate (LiBOB) and fluoroethylene carbonate (FEC) are found more effective and the combination shows to be more promising. In the optimized electrolyte, natural graphite anode exhibits excellent long-term cycling capability. After 800 cycles at high temperature, the capacity retention is comparable to that using artificial graphite. The mechanisms for the capacity-fading of the full cells with AG and NG anode are investigated by ICP, SEM and polarization studies. The results shows that NG electrode consumes more active lithium due to the rough surface and larger volume expansion. The rapid capacity-fading in the initial 100 cycles is related to the instability of the SEI film aroused from large volume expansion. The systematic analysis is inspiriting for the development of high performance lithium ion batteries with reduced cost.

关键词: Lithium ion batteries, Natural graphite, Electrolyte additive, Solid electrolyte interphase