Highly stretchable ionotronic pressure sensors with broad response range enabled by microstructured ionogel electrodes

Stretchable pressure sensors with high sensitivity and wide pressure-response range are ideal for perceiving physical interactions in human health monitoring, soft robotic applications, and human-machine interfaces. However, all existing pressure sensors either show limited stretchability or suffer from narrow response range. Here, we report a highly stretchable ionotronic capacitive pressure sensor (iCPS) that achieves high sensitivity (up to 0.51 kPa(-1)) over a broad pressure range (up to 1 MPa), even under 100% in-plane tensile deformation, enabled by the synergy of a stretchable, bio-inspired microstructured ionogel electrode and a contact area-controlled sensing mechanism. Such sensors show real-time accurate recognition of subtle human physiological signals and identification of object hardness. Moreover, a sensor array with spatial resolution has been fabricated with the successful input of letters in Morse code under different gestures. It is expected that the highly stretchable microstructured ionogel electrodes are widely applicable to other types of stretchable sensors to achieve higher stretchability, together with high sensitivity over a wide response range.