Next Energy (Sep 2023)

Tuning solid electrolyte interface against oxygen/superoxide-derived attack on Li-metal anode in Li-O2 battery

  • Zhengang Li,
  • Suting Weng,
  • Xiaohong Wu,
  • Cun Song,
  • Xiaoyu Yu,
  • Haitang Zhang,
  • Shiyuan Zhou,
  • Xin Wang,
  • Xuefeng Wang,
  • Yu Qiao,
  • Shi-Gang Sun

Journal volume & issue
Vol. 1, no. 3
p. 100036

Abstract

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Practical working environment (O2-saturated base electrolyte), architecture and operation mechanism/processes of Li-O2 batteries (LOBs) endows severe O2 and superoxide (O2-)-derived attack on Li-metal and solid electrolyte interface (SEI) at Li/electrolyte interface, limiting stability of Li anodes and LOBs. Herein, how O2/O2--derived attack on Li-metal and structure/composition of SEI are revealed by cryogenic transmission electron microscopy (cryo-TEM) and comprehensive spectroscopic characterizations. Specifically, generated from O2-reduction on Li-anode, the Li2O-induced nucleophilic attack on base electrolyte decomposition and Li corrosion especially during long-term aging, and more aggressive O2- created in cycling aggravates Li anodes and SEI. Moreover, to address O2/O2--derived attack on Li-metal, 1, 2-difluorobenzene (F-ben) was introduced as cosolvent in base electrolyte to make an F-ben electrolyte, in which F-ben preferentially reacted with Li-metal to form dual-functional SEI. Tuned SEI not only separate Li2O from bulk electrolyte thus suppresses O2-derived chemical attack, also acts as protective film protecting Li-metal against O2- attack. Eventually, electro-stability/reversibility of Li-metal in practical working environment of LOBs and battery performance of LOBs are significantly enhanced with help of F-ben cosolvent. This work sheds light on behavior of O2/O2--derived attack on Li-metal and SEI, sets an effective and practicable path towards practical applications of LOBs.

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