Flexible graphene pressure sensor based on sponge sewn with cotton

High sensitivity and large working range are both essential for flexible pressure sensors. However, there are irreconcilable contradictions between sensitivity and working range. Herein, we manufactured flexible pressure sensors whose sensitivity and working range can be designed customly. The sensors are fabricated by soaking sponges sewn with cotton in graphene inks and their sensitivity and working range can be freely adjusted. Depending on the sponge density and sewing method, the obtained sensors could exhibit different features: some have high sensitivity (up to 4.44 kPa⁻¹), some have large working range (up to 50 kPa) and some are linear, but all of them have good flexibility and outstanding stability. These sensors show excellent performance when applied to walking detection, wrist pulse detection and paper piano. The flexible and changeable performance of the sensors along with the low-cost and scalable fabrication makes them competitive in wearable electronic devices.