Iontronics for adaptive and flexible pressure sensing

Flexible pressure sensors are vital for electronic skin, wearable electronics, and soft robotics. However, conventional electronic pressure sensors based on solid-state dielectrics suffer from limited dielectric tunability, mechanical instability, and static-dynamic response crosstalk, constraining their overall sensitivity and adaptability. Iontronics overcomes these constraints by introducing ionic dielectrics that form nanoscale electrical double layers (EDLs), where interfacial ion migration and polarization yield ultrahigh capacitance, high sensitivity, and dynamic adaptability. This iontronics mechanism not only enhances sensitivity and durability but also offers intrinsic biocompatibility and resistance to electromagnetic interference. Here, we systematically analyze the working principles, key performance determinants, and enhancement strategies of flexible iontronic pressure sensors, emphasizing the roles of EDL formation, ion migration, and interfacial capacitance in determining sensitivity, dynamic response, and long-term stability. Mechanistic insights and materials-structure-mechanism integration are discussed to provide guidance for rational device design and performance optimization in advanced tactile, wearable, and soft electronic systems.