Influence of Hierarchical Biochar Architectures on Dielectric and Triboelectric Behavior of PHBV Composites

ABSTRACT

Developing sustainable polymer composites with enhanced mechanical robustness and electrical performance is essential for next‐generation biodegradable electronic devices. In this work, biodegradable poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) composites were fabricated by integrating particulate biochar derived from Quercus acutissima wood (MLB) with a hierarchical luffa‐derived biochar (LB) network. The layered LB framework reinforced the composite while increasing the density of conductive–insulating heterogeneous interfaces, thereby promoting Maxwell–Wagner–Sillars (MWS) interfacial polarization. The optimized composite containing four LB layers (4LB) exhibited a flexural strength of 19.86 MPa, a flexural modulus of 447.20 MPa, an open‐circuit voltage of 100.76 V, and a short‐circuit current of 6.83 µA, achieving the best overall mechanical and triboelectric performance. Although the dielectric constant increased continuously with increasing LB content, excessive LB incorporation (6LB) promoted localized electrical conduction and dielectric loss as the composite approached the percolation threshold, resulting in charge leakage and reduced triboelectric output. COMSOL simulations further confirmed that the hierarchical LB architecture homogenized the internal electric‐field distribution and enhanced electrostatic induction. These findings demonstrate that synergistic regulation of hierarchical architecture and conductive carbon content provides a promising strategy for simultaneously optimizing the mechanical, dielectric, and triboelectric properties of biodegradable polymer composites for sustainable self‐powered electronic applications.