A super-capacitive pressure sensor with ultrahigh sensitivity and wide linear pressure sensing range for human bio-signal detection and electronic skin

Soft super-capacitive sensors offer several advantages, including mechanical flexibility, high sensitivity, and rapid response, primarily due to the use of soft ionic elastomers and the electrical double layer (EDL) sensing mechanism. As for those sensors, achieving a broad linear pressure sensing range remains crucial, particularly when paired with a well-defined microstructure in the electrolyte layer, which enhances sensor repeatability and facilitates quality control. In this study, a novel design strategy is proposed to simultaneously enhance sensitivity and extend the linear sensing range by integrating a hierarchical dome microstructure within the electrolyte layer and incorporating a curvilinear design in the top electrode. Specifically, the optimized sensor shows an ultrahigh sensitivity (34.79 nF kPa⁻¹), a wide linear sensing range (0–800 kPa), high pressure resolution (0.1%), and stable capacitance responses for dynamic pressure even at high pressure conditions (200 kPa). Moreover, the sensor is successfully examined to perform the detection of human bio-signals, including body movement, respiration pattern recognition, and wrist pulse detection. Additionally, the sensor demonstrates strong potential for serving as an electronic skin (e-skin), as it enables accurate object weight estimation and object identification through machine learning techniques, achieving 100% classification accuracy.