Non-Flammable Ester Electrolyte with Boosted Stability Against Li for High-Performance Li Metal Batteries

Zhijie Wang; Yanyan Wang; Baohua Li; James C Bouwer; Kenneth Davey; Jun Lu; Zaiping Guo

doi:10.1002/anie.202206682

Non-Flammable Ester Electrolyte with Boosted Stability Against Li for High-Performance Li Metal Batteries

Angew Chem Int Ed Engl. 2022 Oct 10;61(41):e202206682. doi: 10.1002/anie.202206682. Epub 2022 Sep 5.

Authors

Zhijie Wang^{1

2}, Yanyan Wang¹, Baohua Li³, James C Bouwer⁴, Kenneth Davey¹, Jun Lu⁵, Zaiping Guo^{1

2}

Affiliations

¹ School of Chemical Engineering & Advanced Materials, The University of Adelaide, Adelaide, SA 5005, Australia.
² Institute for Superconducting & Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, Wollongong, NSW 2522, Australia.
³ Shenzhen Key Laboratory on Power Battery Safety and Shenzhen Geim Graphene Center, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
⁴ Molecular Horizons and School of Chemistry and Molecular Bioscience, Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW 2522, Australia.
⁵ Argonne National Laboratory, Lemont, IL 60439, USA.

Abstract

In traditional non-flammable electrolytes a trade-off always exists between non-flammability and battery performance. Previous research focused on reducing free solvents and forming anion-derived solid-electrolyte interphase. However, the contribution of solvated anions in boosting the stability of electrolyte has been overlooked. Here, we resolve this via introducing anions into Li⁺ solvation sheaths using anions with similar Gutmann donor number (DN) to that of solvents. Taking trimethyl phosphate fire-retardant (DN=23.0 kcal mol^-1 ) and NO₃ ^- (DN=22.2 kcal mol^-1 ) as an example, NO₃ ^- is readily involved in the Li⁺ solvation sheath and reduces the polarity of solvent. This results in boosted stability of electrolyte against Li. The developed non-flammable electrolyte has low viscosity, high ionic conductivity and is low cost. The reversibility of Li-Cu cell was improved to 99.49 % and the lifespan of practical LMBs was extended by >100 %.

Keywords: High Coulombic Efficiency; High Stability; Li Metal Battery; Non-Flammable Electrolyte.

Abstract

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