Revealing the Anion–Solvent Interaction for Ultralow Temperature Lithium Metal Batteries

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Volodymyr Koverga
  • An Phan
  • Ai min Li
  • Nan Zhang
  • Minsung Baek
  • Chamithri Jayawardana
  • Brett L. Lucht
  • Anh T. Ngo
  • Chunsheng Wang

Related Research Unit(s)

Detail(s)

Original languageEnglish
Article number2306462
Journal / PublicationAdvanced Materials
Publication statusOnline published - 27 Nov 2023

Abstract

Anion solvation in electrolytes can largely change the electrochemical performance of the electrolytes, yet has been rarely investigated. Herein, three anions of bis(trifluoromethanesulfonyl)imide (TFSI), bis(fluorosulfonyl)imide (FSI), and derived asymmetric (fluorosulfonyl)(trifluoro-methanesulfonyl)imide (FTFSI) are systematically examined in a weakly Li+ cation solvating solvent of bis(3-fluoropropyl)ether (BFPE). In-situ liquid secondary ion mass spectrometry demonstrates that FTFSI and FSI anions are associated with BFPE solvent, while weak TFSI/BFPE cluster signals are detected. Molecular modeling further reveals that the anion–solvent interaction is accompanied by the formation of H-bonding-like interactions. Anion solvation enhances the Li+ cation transfer number and reduces the organic component in solid electrolyte interphase, which enhances the Li plating/stripping Coulombic efficiency at a low temperature of −30 °C from 42.4% in TFSI-based electrolytes to 98.7% in 1.5 m LiFTFSI and 97.9% in LiFSI-BFPE electrolytes. The anion–solvent interactions, especially asymmetric anion solvation also accelerate the Li+ desolvation kinetics. The 1.5 m LiFTFSI-BFPE electrolyte with strong anion–solvent interaction enables LiNi0.8Mn0.1Co0.1O2 (NMC811)||Li (20 µm) full cell with stable cyclability even under −40 °C, retaining over 92% of initial capacity (115 mAh g−1, after 100 cycles). The anion–solvent interactions insights allow to rational design the electrolyte for lithium metal batteries and beyond to achieve high performance. © 2023 Wiley-VCH GmbH.

Research Area(s)

  • Anion solvation, asymmetric, electrolyte design, Li metal batteries, low temperature

Citation Format(s)

Revealing the Anion–Solvent Interaction for Ultralow Temperature Lithium Metal Batteries. / Xu, Jijian; Koverga, Volodymyr; Phan, An et al.
In: Advanced Materials, 27.11.2023.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review