Extended Stability Window in Water-in-Salt Electrolytes: Understanding the Origins.

ABSTRACT: Water-in-salt electrolytes extend the voltage stability range beyond that of dilute systems, enabling the use of high-voltage materials in aqueous energy storage. This stability is often attributed to the formation of a solid electrolyte interphase (SEI) or reduced water activity. However, by studying the hydrogen evolution reaction (HER) on platinum in NaClO₄ electrolytes (1-17 molal) using electrochemical measurements, MD simulations, and DFT calculations, we show that alternative mechanisms strongly influence the stability window. Specifically, we disentangle the effects from water activity, the local pH increase, and kinetic and transport limitations arising from disrupted hydrogen bonding and sluggish water transport. We observe a nearly linear relationship between the decr

SUBMITTER: Gomez Vazquez D 

PROVIDER: S-EPMC12498405 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature