Flexible pressure sensor decorated with MXene and multi-walled carbon nanotube composites for motion monitoring and electronic skin

Flexible pressure sensors have broad application prospects in artificial intelligence, wearable devices, smart robotics, and other fields. However, developing high-performance flexible pressure sensors remains an enormous challenge. In this study, we report a piezoresistive sensor using low-cost MXene and multi-walled carbon nanotubes (MWCNTs) mixed in porous melamine sponge. The effects of dip-coating sequence and material combination on the resistance and sensitivity of the pressure sensor are studied in detail. The results show that the MXene/MWCNTs melamine sponge pressure sensor has the minimum resistance and the highest sensitivity (8.73 kPa⁻¹). In addition, the sensor has the advantages of short response/recovery time (0.13 s/0.32 s), a low pressure detection (4.1 Pa), and reliable repeatability (5000 cycles). The MXene/MWCNTs melamine sponge pressure sensor can accurately detect different human activities and physiological signal. Moreover, the pressure sensors can construct a matrix acting as electronic skin to detect the magnitude and distribution of external pressure. It is important to highlight that the manufacturing procedure of the pressure sensor is low-cost, simple, environmentally friendly, and establishes a certain foundation for potential industrial and commercial applications.