Fluorinated Barium Titanate Nanoparticles for Wearable Piezoelectric Power Generation

In this paper, to improve the compatibility of poly(vinylidene difluoride) (PVDF) with barium titanate (BaTiO3) and the piezoelectric property of wearable piezoelectric nanogenerators (PENGs), fluorinated BaTiO3 (F-BaTiO3) nanoparticles were prepared by the simple thermal annealing of BaTiO3 prepolymer with PVDF powder, a modified composite nanofiber was prepared by electrospinning with a dispersed liquid consisting of F-BaTiO3 nanoparticles and PVDF solution, and a PENG was prepared with the modified composite nanofiber as a piezoelectric functional material. Scanning electron microscopy (SEM) showed that F-BaTiO3 nanoparticles were more uniformly dispersed in the modified composite nanofiber than BaTiO3 nanoparticles, the analysis of Fourier infrared (FT-IR) spectroscopy showed that the β-phase content of the modified composite nanofiber compounded with F-BaTiO3 (F-BaTiO3/PVDF nanofiber) was higher than that of the modified composite nanofiber compounded with BaTiO3 (BaTiO3/PVDF nanofiber), and when the dosage of F-BaTiO3 nanoparticles was 5 wt %, the β-phase content of the modified composite nanofiber reached the maximum value (91%), which was about three times that of BaTiO3/PVDF nanofiber. The output voltage of the PENG could reach as high as 1.5 V under an external force of 2N and does not decrease obviously after 300 cycles in a vertical pressing test. Furthermore, PENG was demonstrated to be sensitive to the detection of human motions, for instance, elbow flexion, hand slapping a table, and walking. These results indicated that by BaTiO3 being fluorinated with PVDF, the dispersity of F-BaTiO3 in PVDF nanofiber, the β-phase content of F-BaTiO3/PVDF nanofiber, and the output voltage of F-BaTiO3/PVDF PENG were improved.