Flexible Iontronic Sensing: Ionic Materials, Electrodes, and Encapsulation

Abstract Soft iontronic pressure sensors, utilizing the supercapacitive nature of the electric double layers, present advantages of exceptional sensing properties, including high sensitivity over a broad range, and high flexibility. This sensing modality has become an important branch of flexible pressure sensing technologies since its inception 13 years ago. There is a strong correlation between the properties of materials and sensing performances of iontronic sensors, while existing work often focuses on active materials only. Herein, key materials of iontronic sensors are reviewed, including soft ionic conductors, electronically conductive materials, and encapsulating materials, among which encapsulating materials have seldom been discussed before, while this class of materials plays a key role in stable functionality. The molecular structure‐sensing property correlation of electronic electrodes and soft ionic materials is discussed. Potential future directions of iontronic pressure sensors and their applications in robotics and biomedical devices are also discussed at the end of this review article.