Compressive Sponge Electrodes Enabled Highly Sensitive Hybrid-Iontronic Pressure Sensor

Most iontronic pressure sensors with planar metallic electrodes exhibit significant performance degradation in the medium to high-pressure range. To achieve high sensitivity in a broad sensing range, compressive porous electrodes (CPE) were employed to fabricate an ultrasensitive hybrid-iontronic pressure sensor. The sensor demonstrates an ultrahigh sensitivity of 198,160 kPa^-1, a pressure resolution of 4.9 Pa, and a broad sensing range extending up to 160 kPa. Notably, the sensor maintains a nearly linear relationship between sensitivity and pressure within the sensing range of 37.5-92.5 kPa. This approach addresses the issue of significantly attenuated sensitivity across a broad pressure range, which arises from the limited thickness variation of planar electrodes. This composite structure, which integrates CPE with ion-loaded PU foam, offers a straightforward, cost-effective, and scalable method for producing ultrasensitive iontronic pressure sensors. The concept demonstration confirmed that CPE-based pressure sensors are capable of sensitively detecting subtle underwater mechanical stimuli, including vibrations and water waves.