Nanoconfined iontronics and its electronic applications

Iontronics based on nanoconfined effects exhibit enhanced ion dynamics and have become more important in the fields such as energy harvesting and storage, sensors, and human-machine communications, which maybe an alternative or supplementary solution to electronics due to their biocompatibility and safety. The enhanced ion dynamics can be attributable to the strong interactions between ions and the electrical double layer (EDL) in the nanoconfined spaces. Therefore, in this review, an overview of the EDL is firstly provided, with its distinctive nanoconfined effects in governing ion dynamics highlighted. The primary material frameworks associated with nanoconfined spaces, including nanopores, nanochannels, and multidimensional nanostructures, are systematically classified. Strategies for modulating ion dynamics through external physical and chemical fields are explored, forming the basis for iontronic applications driven by nanoconfined effects. These applications are presented, encompassing iontronic power sources, sensors, logic components such as memristors, diodes, and transistors, as well as iontronic filter capacitors, with their unparalleled advantages in biosafety, flexibility, cost-effectiveness, and environmental adaptability emphasized. Finally, existing challenges in nanoconfined iontronics are addressed, with the expectation that advancements in nanoconfined iontronics will catalyze more efficient energy and information flow.