Enhanced High-Temperature Capacitive Energy Storage in Polynorbornene Nanocomposites Enabled by Functional Side-Chain...

Area of Science:

• Materials Science
• Polymer Science
• Electrical Engineering

Background:

• The growing electrical and electronic fields require polymer film capacitors with high energy storage density under extreme conditions.
• Polynorbornene dielectrics face challenges in balancing thermal stability and breakdown strength.

Purpose of the Study:

• To engineer polynorbornene dielectrics with enhanced thermal stability and breakdown strength for high-performance capacitors.
• To address the contradictory relationship between thermal stability and breakdown strength in polynorbornene dielectrics.

Main Methods:

• Utilized molecular engineering with large-adamantine and rigid-biphenyl side-chains for heat resistance.
• Employed nano-filler engineering with hybrid β-cyclodextrin (β-CD)@TiO₂ nanofillers for improved breakdown strength.
• Incorporated biphenyl and anhydride units to optimize space for host-guest complexation.

Main Results:

• Achieved a high glass transition temperature of 265°C in ternary copolynorbornene films (A₈-T₁-B₁).
• Hybrid β-CD@TiO₂ nanofillers created deep traps and physical crossing points, significantly boosting breakdown strength.
• The 0.1% β-CD@TiO₂/A₈-T₁-B₁ composite film demonstrated discharged energy densities of 5.0 J/cm³ at 150°C and 4.3 J/cm³ at 200°C.

Conclusions:

• Developed a novel strategy for scalable, high-temperature-resistant polymer dielectrics.
• Achieved superior energy storage performance and high efficiency (>90% at 150°C, >80% at 200°C) in composite films.
• This approach offers a new pathway for advanced polymer dielectrics in demanding applications.