MXene/cellulose nanofiber-foam based high performance degradable piezoresistive sensor with greatly expanded interlayer distances

High performance flexible pressure sensors have attracted widespread attention due to their potential application in wearable electronics, health monitoring, soft robotics, and more. However, a majority of microstructure designs used for fabricating high-performance pressure sensors need both complicated preparation process and high production cost. Besides, the sensing materials can't get completely degraded in most instances. Thus, ecofriendly and low-cost devices with not only splendid sensing performance but also simple preparation method and degradable raw materials, still need to be explored. Hence, a neotype MXene/cellulose nanofiber (CNF)-foam based piezoresistive sensor is reported. Profiting from particular cellular microstructure of the hybrid foam, the prepared pressure sensor reveals high sensitivity for broad linear ranges (419.7 kPa-1 for 0-8.04 kPa and 649.3 kPa-1 for 8.04-20.55 kPa), low detection limit (4 Pa), rapid response/recover time (123/139 ms) and excellent durability (10,000 cycles). Besides, the device is capable of detecting human activities, recording sound spectrum of music from player software in smartphone and distinguishing tiny difference of grains. And the latent applications of being regarded as commercial light emitting diodes (LEDs) circuit protectors, wireless Bluetooth potential-danger detection devices and paper-based eco-friendly flexible electronics are also explored. Moreover, MXene/CNF-foam can be completely degraded by a very low-concentration H2O2 solution, meeting the demand for green sustainable development commendably.