Ultrahigh augmentation of flexible composite-based piezoelectric energy harvesting efficiency via polymer-impregnated nanoparticles network within 3D cellulose scaffold

In the past decade, many flexible piezoelectric energy harvesters (PEHs) that can convert ambient mechanical energy into electrical energy have been developed, which provides a sustainable power source for wearable/implantable devices and Internet of Things (IoTs) applications. However, the performance of flexible composite-type PEHs should be further optimized to meet the standard for future practical applications. Herein, we present a powerful strategy for high-performance piezoelectric energy harvesting with poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE))-impregnated BaTiO₃ nanoparticles network within 3-dimensional (3D) cellulose scaffold. We propose three methodologies to precisely adjust the microscopic morphology of the organic-inorganic hybrid piezoelectric composites. The construction of methyl cellulose scaffold results in effective stress transfer with high mechanical flexibility as well as dramatically enhanced energy harvesting output. When the cellulose content is 3 wt%, the optimal energy harvesting performance is obtained, which shows the power density of 42 μW/cm³, which is nearly 800% higher than that of the conventional flexible piezoelectric composites previously reported. Throughout the finite-element simulation and mechanical property quantification, the highly augmented energy harvesting capability of our optimal composite structure is determined to stem from the stress-enforced characteristics. Given the ease of fabrication and scalability, this work opens up the way for the development of flexible and high-performance energy harvesting applications.