Title: Probing far-from-equilibrium dynamics of electrical double layers

Authors: Li, Xiao-Yu; Cai, Yu-Chen; Meng, Zhao-Dong; Jia, Ze-Tong; Sun, Yu-Chen; Ye, Jin-Yu; Tian, Na; Zhou, Zhi-You; Huang, Jun; Chen, Junxiang; Sun, Shi-Gang; Wang, Tao

Abstract: Electrified solid–liquid interfaces are central to energy and matter conversion in biological 1 and electrochemical systems 2 , 3 , 4 , in which intense local electric fields govern reaction kinetics 5 , 6 , 7 , 8 , 9 . Yet, under realistic electrocatalytic conditions involving rapid charge transfer and far-from-equilibrium dynamics, the molecular structure and evolution of the electrical double layer (EDL) remain poorly understood. Classical EDL models, derived under equilibrium and non-reactive conditions, cannot capture the interfacial processes emerging at reactive interfaces 10 , 11 , 12 , 13 , 14 , 15 , 16 . Here we develop an integrated experimental–computational framework to directly resolve EDL dynamics under the hydrogen evolution reaction (HER). Chemically stable nanostructured Pt film electrodes enable high-sensitivity, time-resolved surface-enhanced infrared absorption spectroscopy (SEIRAS) at increased overpotentials, whereas machine-learning molecular dynamics (MLMD) captures interfacial charge fluctuations and solvent dynamics over nanosecond timescales. This combined approach reveals a nonlinear, two-phase evolution of the inner layer that intensifies the local electric field. Time-resolved spectra further uncover irreversible restructuring of interfacial water during cyclic potential modulation. These findings show that ions and interfacial water respond asynchronously under the condition far from equilibrium, establishing a quantitative molecular framework for understanding electrostatic potential variations, interfacial electrostriction of ions 17 , 18 , 19 , electrolyte effects 20 , 21 , 22 , 23 , 24 and rational electrolyte design for energy conversion technologies.

Full-Link: https://www.nature.com/articles/s41586-026-10986-7