Strengthened O-H Bonds in an Aqueous Electrolyte for Nonflammable Li-Ion Batteries

Shengxi Li, Yanxin Shang*, Xuening Ren, Anqi Zhao, Nan Chen, Li Li, Feng Wu, Renjie Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Aqueous lithium-ion batteries (ALIBs) have attracted increasing attention for their inherent safety and environmental benefits. However, the narrow electrochemical stability window of water (1.23 V) imposed by hydrogen evolution reaction (HER) and high melting point (0 °C) critically limits the energy density and low-temperature operation. In this work, we report an electrolyte design principle that water activity can be suppressed by strengthening the O-H bonds between water molecules and regulating the pH. A strong polar solvent N,N-dimethylformamide (DMF) interacts with H2O through intermolecular hydrogen bonds, thereby reinforcing the covalent O-H bonds of water. Meanwhile, KOH renders the electrolyte alkaline, inhibiting water dissociation kinetics and consequently raising the HER overpotential. The designed LD1.7W0.6-KOH electrolyte exhibits a freezing point below −82 °C and expanded electrochemical stability window of 4.3 V. The 2.5 V aqueous LiMn2O4/Li4Ti5O12 full cell delivers 2000 cycles at a rate of 6 C with a Coulombic efficiency of 99% at 30 °C and over 1950 cycles at 0 °C. This work offers atomic-level insights into alkaline HER while providing guidance for advancing low-temperature aqueous batteries by tuning the electrolyte structures.

Original languageEnglish
Pages (from-to)16584-16596
Number of pages13
JournalACS Nano
Volume19
Issue number17
DOIs
Publication statusPublished - 6 May 2025

Keywords

  • aqueous electrolyte
  • hydrogen bonds
  • lithium-ion batteries
  • nonflammable
  • O−H bonds

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