Oscillating lithium ion-acceptor fluorine-donor electrolytes for practical fast-charging high-energy lithium metal pouch cells

Abstract

High-voltage Li metal batteries (LMBs) are promising high-energy-density energy storage solutions. However, achieving fast-charging under practical conditions has been a formidable challenge. Here, we synthesized 2-fluoro-1,1-dimethoxy-ethane (FDMN) with a super-lithiophilic fluorine group as a strategical co-solvent to address the long-standing dilemma between rapid Li+ transport in bulk electrolytes and stable electrode–electrolyte interphases. As a Li+ acceptor, FDMN shows a unique oscillating feature to enable fast Li+ exchange across solvation complexes due to the asymmetric polar fluorine site, achieving a high Li+ transference number of 0.80. As a fluorine donor, the strong fluorine-donating ability of FDMN facilitates the formation of an amorphous inorganic SEI interlaced with nanocrystalline Li2O on the Li metal anode and a LiF-rich CEI on the high-voltage cathode. FDMN-based electrolytes improve Li coulombic efficiency under high current densities and enable excellent 1C/2C fast-cycling for 4.5 V nickel-rich LMBs with inhibited Li dendrite growth and Li consumption. Significantly, for the first time, a practical 2 A h NMC811‖Li pouch cell (412 W h kg−1 energy density based on the total mass) with a lean electrolyte (1.5 g A h−1) achieves over 120 stable cycles under 1C fast-charging and 2C fast-discharging. This electrolyte design principle presents an encouraging approach for realizing practical fast-charging high-energy-density LMBs.

Graphical abstract: Oscillating lithium ion-acceptor fluorine-donor electrolytes for practical fast-charging high-energy lithium metal pouch cells

Supplementary files

Article information

Article type
Paper
Submitted
13 Jan 2025
Accepted
09 May 2025
First published
23 May 2025

Energy Environ. Sci., 2025, Advance Article

Oscillating lithium ion-acceptor fluorine-donor electrolytes for practical fast-charging high-energy lithium metal pouch cells

D. Ruan, Y. Wang, J. Guo, Z. Cui, Q. Nian, Z. Ma, D. Wang, J. Fan, J. Ma, B. Xiong, Q. Dong, R. Cao, S. Jiao and X. Ren, Energy Environ. Sci., 2025, Advance Article , DOI: 10.1039/D5EE00227C

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