Assembly of Bone-Inspired Cellulose-Based Dielectric Materials with Highly Oriented Structures and Superior Dielectric Properties toward Advanced Energy Storage

The organic-inorganic structure assembly and recombination of biological materials in nature fully demonstrate their remarkable advantages, enabling the maximum utilization of each component's functions and achieving excellent comprehensive performance. Herein, inspired by the organic/inorganic-phase staggered orientation structures of biological bone, we propose an organic/inorganic-phase orientation strategy for assembling high-performance biomass-derived dielectric composite materials, where the silver-decorated hydroxyl hydroxyapatite (Ag/PDA@HA) nanowires are successfully synthesized and dispersed into a cellulose matrix, and simultaneously, a highly oriented interpenetrating network of nanowires within the matrix is constructed via a stretching force-driven action. In this way, these two incompatible nanophases achieve excellent interfacial combination through strong hydrogen bonds, thereby obtaining well-structured stability and superior dielectric performance. The resultant composite films with 10 wt % Ag/PDA@HA nanowires in the cellulose matrix yield excellent breakdown strength (455.92 MV m^-1), energy storage density (9.91 J cm^-3) and charge-discharge efficiency (86.2%), significantly superior to some previously reported polymer-based dielectric materials. Besides, the excellent thermal properties of composite films, serving as a positive addition, provide important guarantees for the heat dissipation of dielectric energy storage capacitors. Overall, whether from the perspective of environmentally friendly materials or the excellent comprehensive performance of bone-inspired cellulose-based dielectric capacitors, this study has brought about significant innovations in the development of high-performance biomass-derived dielectric materials for advanced energy storage systems.