グラフェンナノポアにおける水和殻交換速度論とイオン移行エネルギー障壁の橋渡し

Ion transport across angstrom-scale graphene nanopores is governed by hydration-shell dynamics, yet the kinetic origin of the associated translocation energy barrier remains unresolved. Here, we bridge hydration-shell exchange kinetics and ion translocation energy barriers by resolving water residence events during pore crossing. Ionic conductance measurements establish the angstrom-scale confinement regime of graphene nanopores, within which molecular dynamics simulations are employed to analyze hydration-shell dynamics. We implement a residence-time analysis that decomposes hydration-shell water behavior into confinement-induced dehydration, regular water exchange, and thermal fluctuations. This analysis enables a quantitative determination of the number of hydration waters irreversibly removed during translocation. For both K⁺ and Mg²⁺, the extent of irreversible dehydration increases monotonically with the translocation energy barrier. These results identify hydration-shell exchange kinetics as the molecular-level determinant of ion transport barriers, providing a dynamically grounded and physically transparent picture of ionic transport under extreme nanoconfinement.