New polymer blend sets energy storage record for high-temperature electronics

A new polymer blend breaks energy storage records

Researchers have created a new type of all-polymer material that can store record-breaking amounts of electrical energy at extremely high temperatures. The work, published in Nature, addresses a critical bottleneck for electronics in electric vehicles, aerospace, and the power grid.

Effective dielectric materials for capacitors need a tricky combination of properties: a high dielectric constant (K) to store charge, low electrical loss to prevent waste heat, and high breakdown strength (Eb) to withstand powerful electric fields. They must also operate reliably when hot.

For decades, scientists have tried mixing polymers with inorganic fillers to improve these metrics, with limited success. The new study takes a different approach by blending two specially chosen polymers that don't naturally mix.

Nanostructures emerge from immiscible blends

The team used high-temperature blends of two distinct dipolar polymers. Because they are immiscible, the materials spontaneously separate at the nanoscale, self-assembling into a three-dimensional all-polymer nanocomposite.

This nanophase separation induces crucial morphological changes in the polymer chains. "The resulting nanostructures induce coiled-chain morphology and large conformation changes," the authors write. This unique structure is key to the material's performance.

Combined with the polymers' low rotational barrier and high dipole moments, the structure yields an ultrahigh dielectric constant (K > 13) while maintaining a remarkably low loss (tan δ ≈ 0.002) across a wide temperature range.

Interfaces block charge, boosting efficiency

The nanostructured interfaces within the material serve a second vital function. They act as barriers for mobile charges, which dramatically reduces conduction losses at high electric fields and temperatures.

This dual action—enhancing dielectric response while suppressing loss—is what sets the new material apart. It achieves what composite approaches have struggled with: concurrently high K, high Eb, and low loss.

The result is unprecedented energy storage density at temperatures where most polymer dielectrics fail. The discharged energy densities are 18.7 J cm⁻³ at 150°C, 15.1 J cm⁻³ at 200°C, and 8.6 J cm⁻³ at 250°C.

A universal and tunable new paradigm

The researchers state that the approach is not limited to one specific polymer pair. "The approach is applicable to other immiscible dipolar blends, demonstrating its universality and tunability," the paper notes.

This means the core design principle—using nanophase separation in all-polymer blends to create beneficial nanostructures—can be a platform for developing a new family of materials. It provides a new roadmap for high-energy-density polymer dielectrics.

The work directly tackles urgent needs in modern electrical engineering. High-temperature, high-density capacitors are essential for:

• Power electronics in electric vehicles
• Avionics and propulsion systems in aerospace
• Compact energy storage for renewable power grids

By creating a material that excels where others falter, this research opens the door to more efficient, powerful, and compact electronic systems that can operate in extreme environments.