Dynamic electrical double layers at solid-liquid interfaces for energy-information flow

Abstract

Electrical double layers (EDLs) constitute fundamental electrochemical interfaces that, when dynamically regulated, enable tight coupling between energy transduction and information processing. Recent advances have progressively shifted the role of EDLs from passive, equilibrium charge-screening structures to actively reconfigurable ionic-electronic interfaces, thereby establishing a unified physicochemical framework for solid-liquid triboelectricity, triboiontronics, and the emerging iontrovoltaic effect. Here, we synthesize a dynamic EDL-centered perspective that connects the evolution of EDL theory with recent developments in iontronic systems. This framework outlines a continuous conceptual progression from classical conductive-interface descriptions and the two-step model of non-conductive interfaces to triboiontronic regimes in which mechanically induced charge separation drives dynamic ion polarization and further to semiconductor-liquid interfaces where EDL modulation couples with space charge regions to give rise to the iontrovoltaic effect. In parallel, device architectures evolve from solid-liquid triboelectric nanogenerators to triboiontronic nanogenerators and ultimately to iontrovoltaic nanogenerators, reflecting increasing integration of ionic dynamics with electronic transport. Across these regimes, the functional role of EDLs expands from static charge screening to dynamic electrostatic induction, directional ionic transport, and coupled ionic-electronic modulation. This evolution establishes dynamic EDLs as a general platform for co-regulating energy flow and information flow across solid-liquid interfaces. More broadly, dynamic EDLs provide a unifying ionic framework that links interfacial energy conversion with information processing, offering a physical basis for the development of bioinspired iontronic systems and embodied intelligence.