J. Mater. Sci. Technol. ›› 2022, Vol. 102: 72-79.DOI: 10.1016/j.jmst.2021.05.074

• Research Article • Previous Articles     Next Articles

An advanced cathode composite for co-utilization of cations and anions in lithium batteries

Xiao-Tong Wanga, Yang Yangb, Jin-Zhi Guoa, Zhen-Yi Gua, Edison Huixiang Angc, Zhong-Hui Sund, Wen-Hao Lia, Hao-Jie Lianga, Xing-Long Wua,b,*()   

  1. aMOE Key Laboratory for UV Light-Emitting Materials and Technology, Northeast Normal University, Changchun 130024, China
    bFaculty of Chemistry, Northeast Normal University, Changchun 130024, China
    cNatural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore
    dCenter for Advanced Analytical Science, c/o School of Chemistry and Chemical Engineering, c/o MOE Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Guangzhou University, Guangzhou 510006, China
  • Received:2021-03-17 Revised:2021-04-25 Accepted:2021-05-13 Published:2022-03-10 Online:2021-08-26
  • Contact: Xing-Long Wu
  • About author:*E-mail address: xinglong@nenu.edu.cn (X.-L. Wu).

Abstract:

Anions in the electrolyte are usually ignored in conventional "rocking-chair" batteries because only cationic de-/intercalation is considered. An ingenious scheme combining LiMn0.7Fe0.3PO4 (LMFP@C) and graphite as a hybrid cathode for lithium-ion batteries (LIBs) is elaborately designed in order to exploit the potential value of anions for battery performance. The hybrid cathode has a higher conductivity and energy density than any of the individual components, allowing for the co-utilization of cations and anions through the de-/intercalation of Li+ and PF6- over a wide voltage range. The optimal compound with a weight mix ratio of LMFP@C: graphite = 5: 1 can deliver the highest specific capacity of nearly 140 mA h/g at 0.1 C and the highest voltage plateau of around 4.95 V by adjusting the appropriate mixing ratio. In addition, cyclic voltammetry was used to investigate the electrode kinetics of Li+ and PF6- diffusion in the hybrid compound at various scan rates. In situ X-ray diffraction is also performed to further demonstrate the structural evolution of the hybrid cathode during the charge/discharge process.

Key words: Lithium Batteries, Cathode, Anion De-/Intercalation, Graphite, LiMn0.7Fe0.3PO4