Triboelectric sensor with ultra-wide linear range based on water-containing elastomer and ion-rich interface

The incompatibility of the high sensitivity and wide linear range still restricts the further development of active sensors. Here we report a triboelectric pressure sensor based on water-containing triboelectric elastomer with gradient-based microchannels. Tiny amount of liquid is injected into the triboelectric elastomer and the pressure-induced water bridges can modulate the built-in electric field of the sensor, which enhance the signal linearity near the compression limit. Moreover, it has been found that liquid-solid contact electrification can be enhanced by triggering selective ionic transfer, while the prepared ion-rich interface in the microchannels boosts the sensitivity of the sensor. Hence, an ultra-wide linear range (5 kPa–1240 kPa) with a sensitivity of 0.023 V kPa−1 can be achieved, which is so far the widest linear range of active sensors to our knowledge. Our work can promote the practical application of triboelectric sensors and provide new insights for other sensory devices. The incompatibility between high sensitivity and a wide linear range has hindered the development of sensors. Here, the authors propose a pressure sensor that combines a water-containing triboelectric elastomer with gradient-based microchannels, achieving an ultra-wide linear range and high sensitivity simultaneously.