High-performance Vanillin-derived Dielectric Polymer Films for Sustainable Energy Storage

Dielectric films are critical components in the fabrication of capacitors. However, their reliance on petroleum-derived polymers presents significant environmental challenges. To address this issue, we report on a high-performance biomass-based dielectric material derived from vanillin (VA), a renewable aromatic aldehyde. Vanillin was first esterified to synthesize vanillin methacrylate (VMA), which was then copolymerized with methyl methacrylate (MMA) via free-radical polymerization to yield P(VMA-MMA). By crosslinking the aldehyde groups in VMA with the amine groups in the polyether amine D400 (PEA), we fabricated a series of P(VMA-MMA)@PEA dielectric films with precisely tunable crosslinking densities. The unique molecular structure of vanillin, featuring both a benzene ring and an ester group, facilitates strong δ-π interactions and dipolar polarization, synergistically enhancing energy storage density while minimizing dielectric loss. At an optimal P(VMA-MMA) ratio of 1:10 and 80% theoretical crosslinking degree, the dielectric constant reaches 3.4 at 10³ Hz, while the breakdown strength reaches 670.2 MV/m. Furthermore, the film exhibits an energy storage density of 7.1 J/cm³ at 500 MV/m while maintaining a charge-discharge efficiency exceeding 90%. This study demonstrates a green and reliable strategy for designing biomass-based dielectric materials and opens new avenues for the development of eco-friendly energy-storage technologies.