Fluorinated Rocksalt Cathode with Ultra‐high Active Li Content for Lithium‐ion Batteries Academic Article uri icon

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abstract

  • The key to increasing the energy density of lithium-ion batteries is to incorporate high contents of extractable Li into the cathode. Unfortunately, this triggers formidable challenges including structural instability and irreversible chemistry under operation. Here, we report a new kind of ultra-high Li compound: Li4+x MoO5 Fx (1≤x≤3) for cathode with an unprecedented level of electrochemically active Li (>3 Li+ per formula), delivering a reversible capacity up to 438 mAh g-1 . Unlike other reported Li-rich cathodes, Li4+x MoO5 Fx presents distinguished structure stability to immunize against irreversible behaviors. Through spectroscopic and electrochemical techniques, we find an anionic redox-dominated charge compensation with negligible oxygen release and voltage decay. Our theoretical analysis reveals a "reductive effect" of high-level fluorination stabilizes the anionic redox by reducing the oxygen ions in pure-Li conditions, enabling a facile, reversible, and high Li-portion cycling.

authors

  • Pei, Yi
  • Chen, Qing
  • Ha, Yang
  • Su, Dong
  • Zhou, Hua
  • Li, Shuang
  • Yao, Zhenpeng
  • Ma, Lu
  • Sanders, Kevin J
  • Sheng, Chuanchao
  • Goward, Gillian Ruth
  • Gu, Lin
  • Yu, Aiping
  • Yang, Wanli
  • Chen, Zhongwei

publication date

  • November 21, 2022