Iontronic Capacitive Pressure Sensors With Enhanced Sensitivity Enabled by an Ionic Asymmetric Fiber Mat

Flexible pressure sensors are pivotal for next-generation applications in health monitoring, electronic skin, and human-machine interaction. While iontronic sensors are prized for their high sensitivity, conventional methods to optimize the dielectric layer often involve complex and costly microfabrication. This work presents a high-sensitivity iontronic sensor created from an ionic asymmetric fiber mat (i-AFM) dielectric, fabricated by a simple sequential electrospinning process. This ionic-asymmetric and fibrous design synergistically minimizes initial capacitance while maximizing the pressure-induced interfacial contact area change. The resulting device achieves an ultra-high sensitivity of 47.27 kPa −1 , a wide linear range up to 750 kPa, an ultra-low detection limit of 0.86 Pa, and a fast response/recovery time of 1.92/7.06 ms. The sensor accurately monitors tiny pressures and various physiological signals, including pulse, breathing, swallowing vibration, and joint bending. Furthermore, a 4 × 4 sensor array enables spatial pressure mapping, and integration with a machine learning model achieves >95.00% accuracy in speech recognition. This versatile, high-performance sensing platform holds significant promise for wearable healthcare, soft robotics, and human-machine interaction.