An Overview of Polymer-Based Piezoelectric Nanogenerators Derived from Sustainable Biowaste Materials.

Abstract

The growing global demand for eco-friendly and decentralized energy alternatives has intensified interest in piezoelectric nanogenerators (PENGs) as efficient devices capable of converting mechanical motions from the environment into electrical energy. Among various classes of PENGs, polymer-based systems have gained significant attention due to their flexibility, lightweight nature, ease of processing, and potential for large-scale, cost-effective production. This review presents an extensive assessment of polymer-based piezoelectric nanogenerators developed from renewable biowaste materials, summarizing current progress in materials engineering, composite formulation, fabrication methods, and device configuration. Particular focus is directed toward the utilization of biowaste resources such as cellulose, chitin, keratin, eggshells, fish scales, and lignocellulosic plant residues as reinforcing agents, structural templates, or precursors that improve the dielectric, mechanical, and piezoelectric properties of polymer matrices. The interrelationship between structural characteristics and electrical performance is critically analyzed, considering factors like filler morphology, crystallinity, interfacial bonding, polarization processes, and nanoscale orientation. Various fabrication approaches including electrospinning, solution casting, additive manufacturing, and layer-by-layer deposition are evaluated based on their reproducibility and scalability. Additionally, this review highlights standard characterization protocols and performance indices essential for accurate evaluation across research studies. Persistent challenges such as inconsistent biowaste composition, durability concerns, interfacial incompatibility, and limited device integration are discussed. The paper concludes by outlining potential strategies for performance enhancement through hybridization, hierarchical structuring, and sustainable processing routes, emphasizing applications in wearable technology, autonomous sensors, and environmental monitoring. Overall, this overview consolidates recent advancements while identifying research gaps, providing valuable insights for the continued development of sustainable, high-efficiency polymer-based PENGs that utilize biowaste for green energy harvesting.