High-performance flexible triboelectric nanogenerator based on porous aerogels and electrospun nanofibers for energy harvesting and sensitive self-powered sensing

Finding new means to enhance the performance of triboelectric nanogenerators (TENGs) is an ongoing pursuit. We report a novel flexible TENG made of highly porous cellulose nanofibril (CNF)/polyethylenimine (PEI) aerogel film paired with polyvinylidene fluoride (PVDF) nanofiber mats that exhibits outstanding triboelectric outputs. Modifying CNF with PEI not only enhances the mechanical properties of the CNF/PEI aerogel, but also greatly improves the power density by 14.4 times due to the enhanced tribopositivity. The triboelectric performance is further improved by employing multiple layers of PVDF mats. The TENG made of the CNF/PEI aerogel paired with four layers of PVDF mats exhibited an 18.3 times and 97.6 times improvement in output voltage and power density, respectively, compared to the TENG made of one layer of PVDF mat. The peak output power density reached 13.3 W/m2 at a load resistance of 106 Ω. Furthermore, the novel TENG displays extraordinary sensitivity when used as a self-powered sensor. It can detect not only human motion like arm bending and footsteps, but also small forces like finger tapping, water dripping, and the vibration of the substrate it is attached to. Therefore, this study not only demonstrates a high performance TENG, but also provides new insights into the design, fabrication, and application of TENGs.