A core-shell structured barium titanate nanoparticles for the enhanced piezoelectric performance of wearable nanogenerator

Improving the dispersion of barium titanate (BT) nanoparticle in polyvinylidene difluoride (PVDF) can improve the piezoelectric property of wearable piezoelectric nanogenerators (PENG). In this paper, BT nanoparticles were modified with silane coupling agent (1H, 2H, 1H, 2H, perfluorooctyltriethylsilane, PFOES), and then core-shell structured BT nanoparticles (F@BT nanoparticles) were prepared by thermal annealing of modified BT and used to prepare of F@BT composite functional material and F@BT/PVDF composite PENG. The core-shell structure of F@BT nanoparticles enhanced the stress-transfer efficiency, verified by experimental results and COMSOL simulations. In addition, the F@BT nanoparticles improved the BT nanoparticles dispersion in the PVDF and induced the β phase formation of F@BT/PVDF composite nanofibers film, which greatly improved the piezoelectric output of F@BT/PVDF composite PENG. The F@BT/PVDF composite PENG exhibited an output voltage of up to 2.1 V and a power density of 5.4 μW. In addition, the output voltage of F@BT/PVDF composite PENG remained unchange up to 1000 cycles, demonstrating its excellent stability. The F@BT/PVDF composite PENG could sense human motions, such as wrist bending, elbow bending, and walking. This study introduced a simple and controlled method for preparing highly efficient F@BT/PVDF composite PENG, providing various applications, such as mechanical energy harvesters, motion monitoring, and wearable devices.