High-Performance\nLightweight and Flexible PVDF-B/MXene/Chitosan\nComposite Aerogel for Sensitive Self-Powered Sensing

Piezoelectric devices are becoming increasingly attractive\nin areas\nsuch as wearable electronics, mobile environmental sensors, and health\nmonitoring due to their unique capability to harvest discrete mechanical\nenergy. Nevertheless, most piezoelectric materials are fabricated\ninto low-dimensional products, which limits the performance breakthroughs\nand application prospects of these devices. Here, a series of polyvinylidenefluoride\n(PVDF) doped with dopamine hydrochloride@BaTiO<sub>3</sub>/MXene/chitosan\n(PVDF-B/MXene/CS) composite aerogel piezoelectric devices with outstanding\noutput performance were fabricated by combining electrospinning and\nfreeze-drying techniques. Among them, the PVDF-B/MXene/CS composite\naerogel-based piezoelectric devices with electrodes exhibited rather\nbetter output performance compared to those without electrodes, while\nthe electrodeless piezoelectric devices demonstrated excellent piezoelectric\nresponse under various stress modes. The electrodeless piezoelectric\ndevices maintained a stable voltage over 1800 cycles and achieved\nthe maximum power output of 4.25 nW with an external resistance of\n100 MΩ. Furthermore, the electrodeless piezoelectric device\nwas capable of charging capacitors with varying capacities and could\neasily illuminate a small light emitting diode (LED) light by manual\ntapping. These piezoelectric devices showed tangible and stable signals\nregarding mechanical stimuli monitoring, such as wrist bending, finger\ntapping, and pedal movements. This work not only expands the range\nof aerogel-based piezoelectric materials but also showcases their\nimmense potential in the field of piezoelectric devices.