Supersonic solution blowing of polyvinylidene fluoride/cellulose nanofibers for high-performance piezoelectric nanogenerators

Highly viscoelastic polyvinylidene fluoride (PVDF) nanofibers were prepared by supersonic solution blowing, resulting in the formation of nanoscale pseudo-grain boundaries that enhanced the interfacial polarization and facilitated mechanical energy harvesting in piezoelectric nanogenerators (PENGs). The addition of cellulose acetate (CA) or sodium carboxymethylcellulose (CMCNa) to the PVDF solution increased the content of electroactive γ and β phases in the PVDF/CA and PVDF/CMCNa nanofibers by factors of 2 and 3.3, respectively, and the corresponding piezoelectric potentials by factors of 3 and 6, respectively. The PVDF/CA-based PENG generated a piezopotential output of 12.5 V at a tapping force and frequency of 5 N and 5 Hz, respectively, and the PVDF/CMCNa-based PENG produced a piezopotential output of 28.6 V at a tapping force and frequency of 10 N and 7 Hz, respectively, along with a power density of 31 µW·cm⁻². The versatility of the prepared PENGs was demonstrated for a diverse range of body movements, including walking, running, writing, and finger bending. The optimal PENG can be seamlessly integrated with energy storage systems, thereby supplying power to wearable electronic instruments, such as smart sensors and health-monitoring devices.