Enhanced Energy Harvesting Ability of ZnO/PAN Hybrid Piezoelectric Nanogenerators

Miniaturization of energy conversion and storage devices has attracted remarkable consideration in the application of wearable electronics. Compared with film-based flexible electronics, fiber-based wearable electronics (e.g., nanogenerators and sensors made from electrospun nanofibers) are more appealing and promising for wearables. However, there are two bottlenecks, a low power output and poor sensing capability, limiting the application of piezoelectric nanofibers. Herein, we integrated zinc oxide nanorods (ZnO NRs) to a less known piezoelectric polymer, polyacrylonitrile (PAN) nanofiber, forming a ZnO/PAN nanofabric, which significantly improved the pressure sensitivity and vibrational energy harvesting ability by about 2.7 times compared with those of the pristine PAN nanofiber, and the maximum output power density of ∼10.8 mW·m^-2 is achieved. Noteworthily, the ZnO/PAN nanofabric showed a power output about twice of the one made of ZnO and polyvinylidene fluoride. It was revealed that the integration of ZnO NRs clearly improved the planar zigzag conformation in microstructures of the PAN nanofiber. Further, successful demonstrations of a mechanically robust pressure sensor and wearable power source confirm the potential applications in human activity monitoring and personal thermal management, respectively.