Lewis Acid-Activated Charge Trapping in Dielectric Polymers for Superior High-Temperature Electrostatic Energy...

Area of Science:

• Materials Science
• Polymer Chemistry
• Electrochemistry

Background:

• Dielectric polymer capacitors are key for energy storage but face efficiency losses due to charge transport, especially at high temperatures.
• Current methods to reduce losses involve complex interfaces, hindering scalable manufacturing.
• A homogeneous molecular approach for charge trapping is needed but largely unexplored.

Purpose of the Study:

• To develop a homogeneous molecular trapping mechanism for dielectric polymers.
• To enhance the performance of polymer capacitors, particularly under elevated temperatures.
• To enable high-energy-density storage solutions for demanding thermal conditions.

Main Methods:

• Modified the lowest occupied molecular orbitals of dielectric polymers using Lewis acid-base adducts.
• Incorporated tris(pentafluorophenyl)boron (BCF) as a Lewis acidic additive into polyetherimide (PEI).
• Evaluated the charge trapping, breakdown strength, energy density, and cycle stability of the modified polymer films.

Main Results:

• Achieved homogeneous charge trapping by forming Lewis acid-base adducts within the polymer matrix.
• The PEI-BCF film with 0.5 wt.% BCF showed significantly enhanced breakdown strength.
• Demonstrated an ultrahigh discharged energy density of 7.3 J cm^-3 with excellent cycle stability at 200 °C.

Conclusions:

• Established a facile molecular strategy to decouple charge trapping from heterogeneous interfaces.
• The developed approach enables high-energy-density polymer capacitors that are stable under extreme thermal conditions.
• This molecular modification offers a promising route for advanced energy storage materials.