Synergistic Molecular Engineering of Crosslinked Polymer Dielectrics for High-Temperature Capacitive Energy Storage

Area of Science:

• Materials Science
• Polymer Chemistry
• Energy Storage

Background:

• Polymer dielectric capacitors are crucial for high-temperature energy storage.
• Existing materials struggle with thermal stability and capacitive performance due to conduction loss or insufficient polarization.

Purpose of the Study:

• To design and synthesize novel alicyclic polymers for high-temperature energy storage.
• To overcome the limitations of current materials by simultaneously optimizing molecular polarity, topological crosslinking, and free volume.

Main Methods:

• Modular molecular engineering of norbornene-based monomers.
• Incorporation of benzocyclobutene (BCB) and sulfone-methyl groups.
• Ring-opening metathesis polymerization (ROMP) to create crosslinked networks.
• Molecular dynamics (MD) and density functional theory (DFT) simulations.

Main Results:

• Achieved high thermal stability (glass transition temperature, T_g > 350 °C) and suppressed dissipation (D_f ≈ 0.0006).
• Optimized polymer (P50-B250) delivered 8.00 J cm^-3 discharged energy density at 150 °C with ≥90% efficiency.
• Fully crosslinked polymer (P0-B300) retained significant energy density at higher temperatures (7.34 J cm^-3 at 200 °C, 4.65 J cm^-3 at 250 °C).
• Crosslinking increased free volume by ≈40%, inhibiting charge transfer complexes (CTCs).

Conclusions:

• Established a general framework for designing polymer dielectrics through structural modularity and topological control.
• Demonstrated a pathway for next-generation energy storage applications under extreme conditions.
• Developed high-performance polymer dielectrics surpassing conventional materials.