Synchronous Sound Recognition and Energy Harvesting by Flexible Piezoelectric PLLA/VB 2 Composites.

In the present study, poling-free PLLA/VB 2 piezoelectric composites are fabricated to achieve synchronous sound recognition and energy harvesting. The addition of VB 2 can interact with PLLA by intermolecular hydrogen bonding, inducing the dipole orientation of C=O in PLLA. Meanwhile, VB 2 can promote crystallization of PLLA through heterogeneous nucleation. The combination of the two strategies significantly improves the piezoelectric performance of PLLA/VB 2 composites. The PLLA/VB 2 can detect the sound frequency with an accuracy of 0.1% in the range of 0-20 kHz to recognize characteristic sounds from a specific source. PLLA/VB 2 can also convert sound into electrical energy synchronously with an energy density of 0.2 W/cm -3 to power up LEDs. Therefore, PLLA/VB 2 shows great potential in the field of information and energy synchronous collection.