Ultrafast aqueous electric double layer dynamics

• 成果类型: Article
• 署名作者: Greco, Alessandro; Imoto, Sho; Backus, Ellen H. G.; Nagata, Yuki; Hunger, Johannes; Bonn, Mischa
• 署名单位: Max Planck Society; University of Vienna
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-13967
• DOI: 10.1126/science.adu5781
• 发表日期: 2025-04-25
• 页码: 405-410
• 关键词: water; interface; relaxation; pair; salt

摘要

The electric double layer (EDL) is critical in electrochemical capacitors and transistors, on-water chemistry, and bioelectric technologies. Ion dynamics within the EDL define the limits for charging and discharging processes. Classical EDL models struggle at high electrolyte concentrations, and observing EDL dynamics has been challenging. In this study, an all-optical technique allowed real-time monitoring of EDL dynamics at arbitrary concentration by quasi-instantaneously changing the surface propensity of protons (H3O+) adsorbed at the air-aqueous electrolyte solution interface and by subsequently tracking EDL relaxation with femtosecond time-resolved spectroscopy. EDL reorganization occurred on picosecond timescales and was strongly concentration dependent. Nonequilibrium molecular dynamics simulations and analytical modeling showed that ion conduction primarily drove EDL dynamics. This research quantified EDL dynamics and identified its primary driver, providing insights for optimization of electrochemical applications.