Greco Alessandro, Imoto Sho, Backus Ellen H G, Nagata Yuki, Hunger Johannes, Bonn Mischa
Max Planck Institute for Polymer Research, Mainz, Germany.
Institute of Physical Chemistry, University of Vienna, Vienna, Austria.
Science. 2025 Apr 25;388(6745):405-410. doi: 10.1126/science.adu5781. Epub 2025 Apr 24.
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 (HO) 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.
双电层（EDL）在电化学电容器、晶体管、水相化学和生物电技术中至关重要。双电层内的离子动力学决定了充电和放电过程的极限。传统的双电层模型在高电解质浓度下存在困难，并且观察双电层动力学一直具有挑战性。在本研究中，一种全光学技术通过准瞬时改变吸附在空气-电解质水溶液界面的质子（H⁺）的表面倾向，并随后用飞秒时间分辨光谱跟踪双电层弛豫，实现了在任意浓度下对双电层动力学的实时监测。双电层重组发生在皮秒时间尺度上，并且强烈依赖于浓度。非平衡分子动力学模拟和分析模型表明，离子传导主要驱动双电层动力学。这项研究量化了双电层动力学并确定了其主要驱动因素，为优化电化学应用提供了见解。
