In situ fabrication of ether-in-gel electrolyte enables long-cycle Li–air batteries over a wide temperature range

Abstract

Practical application of lithium–air batteries (LABs) is hindered by volatile liquid electrolytes, which compromise cycling stability at both high and low temperatures. Herein, we propose an in situ strategy for the fabrication of an ether-in-gel electrolyte to enhance their performance. LiN(CH 3 ) 2 (LDA), formed from metallic Li and N,N-dimethylformamide, binds with TEGDME (G4) to create an LDA(G4) 2 matrix that confines liquid G4 and traces of DMF, forming a gel electrolyte. The strong Li + -O/N interaction between LDA and G4 enables high superoxide solubility and high intrinsic thermal stability. LABs with the gel electrolyte exhibit over 1250 h stability (>50 days) in ambient air with high energy efficiency of over 70% and maintain stable cycles (540 h at 55 °C and 800 hours at −20 °C) without significant capacity decay. This work paves the way for design of new ether-in-gel electrolytes for high-energy batteries under all climate conditions. • A facile in situ strategy is proposed for the fabrication of an ether-in-gel electrolyte for LABs to improve the stability of metallic Li anode. • The Li atoms coordinate with N atoms in LDA to form a parallelogram unit structure, which interacts with the G4 solvent to form the matrix, resulting in a stable framework and enhancing the thermodynamic stability and ionic conductivity of the gel electrolyte. • Superfluous G4/DMF solvent molecules have high ionic conductivity at low temperatures and stronger adsorption abilities toward superoxide intermediates, enables the LABs working in wide temperature range.

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