Advances in dielectric polymer composites provide new ways to study ultra-low filler content

Adding inorganic fillers into organic polymers is emerging as the most popular approach for high-energy-density polymers in electrical energy storage applications, including electric vehicles, power transmission, and electromagnetic systems.

Recent advances in the materials, featuring ultra-low filler loadings, have overcome many of the significant drawbacks of polymer composites and offer opportunities to further explore interfaces.

Li et al. provided an overview of the key developments in the dielectric polymer composites with ultra-low small-sized filler content. The group highlighted recent characterizations of the filler-polymer interface and assessed the challenges that lie ahead for scaling such materials into high-energy-density dielectrics.

“The understanding and control of the responses of the multicomponent soft materials to the applied electric field not only require new knowledge, but also introduce unprecedented opportunities for physicists and engineers to work collaboratively in a new domain,” said author Qing Wang.

A small amount of inorganic filler in polymers enhances the dielectric properties of polymer composites and retains melt-processability of polymers.

Recent work has shown that ultra-low fractions of aluminum oxide and other nanofillers improved the dielectric constant of polyetherimide. Two-phase dielectric models cannot explain such improvements.

The paper calls for generalizing the modeling approach to other polymer systems and developing theories to predict performance and guide design.

“Current models cannot fit the dielectric data of the polymer composites with ultra-low filler contents,” Wang said. “This is driving us to come out innovative ideas and work collaboratively across the traditional disciplines.”

The group aims to focus on how the interface affects dielectric properties under applied fields and how to leverage tailored interfaces to enhance their properties.

Source: “Perspective on scalable high-energy-density polymer dielectrics with ultralow loadings of inorganic nanofillers,” by Li Li, Yao Zhou, Yang Liu, Xin Chen, Zhubing Han, and Qing Wang. Applied Physics Letters (2022). The article can be accessed at https://doi.org/10.1063/5.0080825 .