Isotropically Polarized Bipiezoelectric Polyacrylonitrile-Poly(vinylidene Fluoride) Advanced Triboelectric Nanogenerator for Operation in High-Humidity Environments

Conventional hybrid piezo-triboelectric nanogenerators (PTNGs) have potential applications as energy supply devices for microelectronic devices, but their low power density and unstable performance under high-humidity conditions are challenges that need to be solved. Here, we report a novel flexible hybrid bifiezo-triboelectric nanogenerator (Bi-PTNG) based on isotropic polarization design of piezoelectric PVDF and PAN nanofiber membranes, which greatly improves power density of devices and performances in high-humidity conditions. The performance enhancement mechanism of the Bi-PTNG was investigated by model analysis, experimental measurements, and simulations. The results showed that the power density output of Bi-PTNG increased by approximately 88% compared to that of a depolarized PAN/PVDF-based triboelectric nanogenerator (TENG). The application studies demonstrated that a 2 × 2 cm² Bi-PTNG can be directly used to run more than 120 commercial LEDs, and this highly flexible and breathable all-fiber device can be integrated into clothing or insoles to monitor human movement in high-humidity conditions. This work not only provides an effective strategy for enhancing the power output of TENGs and advancing their practical applications but also offers robust guidance for the material selection and optimization of the polarization direction in such nanogenerators.