3D\nNetwork Spacer-Embedded Flexible Iontronic Pressure\nSensor Array with High Sensitivity over a Broad Sensing Range

Abstract

Microstructure\nconstruction is a common strategy for enhancing\nthe sensitivity of flexible pressure sensors, but it typically requires\ncomplex manufacturing techniques. In this study, we develop a flexible\niontronic pressure sensor (FIPS) by embedding an isolated three-dimensional\nnetwork spacer (3DNS) between an ionic gel and a flexible Ti₃C₂T_<i>x</i> MXene electrode, thereby\navoiding complex microstructure construction techniques. By leveraging\nsubstantial deformation of the 3DNS and the high capacitance density\nresulting from the electrical double layer effect, the sensor exhibits\nhigh sensitivity (87.4 kPa^–1) over a broad high-pressure\nrange (400–1000 kPa) while maintaining linearity (<i>R</i>² = 0.998). Additionally, the FIPS demonstrates a rapid\nresponse time of 46 ms, a low limit of detection at 50 Pa, and excellent\nstability over 10 000 cycles under a high pressure of 600 kPa.\nAs practical demonstrations, the FIPS can effectively monitor human\nmotion such as elbow bending and assist a robotic gripper in accurately\nsensing gripping tasks. Moreover, a real-time, adaptive 7 × 7\nsensing array system is built and can recognize both numeric and alphabetic\ncharacters. Our design philosophy can be extended for fabricating\npressure sensors with high sensing performance without involving complex\ntechniques, facilitating the applications of flexible sensors in human\nmotion monitoring, robotic tactile sensing, and human–machine\ninteraction.