Fluorine-abundant inorganic nanoparticles synergistically enhance PVDF-based triboelectric materials for quantitative monitoring of post-exercise stretching

Addressing industrial fluorine waste disposal while enhancing fluorinated triboelectric materials constitutes dual critical challenges. By compounding oxygen-free CaF 2 nanoparticles synthesized from solidified fluoride ions with PVDF, this study achieves simultaneous environmental remediation and triboelectric enhancement. The synergistic mechanisms include: (1) Intrinsic negative triboelectric polarity enhancement (work function increased from 4.97 to 5.31 eV); (2) Aggregated state modulation ( β -phase: 76.8 % to 90.8 %; crystallinity: 43.5 % to 48.9 %); (3) Interfacial polarization (>25 % dielectric constant increase at 1 kHz). The 20 wt% CaF 2 /PVDF composite film exhibits 128 V open-circuit voltage, 43 nC transferred charge, and 403.3 mW/m 2 power density - representing 2.79-fold enhancement over pure PVDF. The composite maintains >95 % output stability through 3000 bending cycles and functions effectively as wearable strain sensors for human motion monitoring. This integrated strategy establishes a sustainable paradigm merging waste valorization with high-performance triboelectric material design.