Colossal electrocaloric effect in an interface-augmented ferroelectric polymer

Area of Science:

• Materials Science
• Condensed Matter Physics
• Polymer Science

Background:

• The electrocaloric effect requires maximizing polar domain degrees of freedom and minimizing polarization transition energy barriers.
• Optimization of these factors in bulk ferroelectrics has reached inherent limitations.
• Existing strategies struggle to overcome the trade-offs between domain size, crystallinity, and polar correlations.

Purpose of the Study:

• To overcome the limitations of bulk ferroelectrics for enhanced electrocaloric effect.
• To develop a new strategy for assembling polar conformations at heterogeneous interfaces.
• To investigate the potential of interface engineering for giant conformational entropy and high entropy change.

Main Methods:

• Utilized organic crystal dimethylhexynediol (DMHD) as a 3D sacrificial template.
• Employed an epitaxy-like process via DMHD evaporation to assemble polar conformations.
• Fabricated poly(vinylidene fluoride)-based terpolymer with an ultrafinely distributed, multiconformation-coexisting polar interface.

Main Results:

• Achieved an ultrafinely distributed polar interface with giant conformational entropy.
• Demonstrated a high entropy change of 100 J/(kg·K) under a low electric field.
• The interface polarization strategy significantly enhanced the electrocaloric performance.

Conclusions:

• The interface polarization strategy using a sacrificial organic crystal is effective in boosting electrocaloric performance.
• This approach offers a generalizable method for enhancing dielectric materials.
• The developed terpolymer shows promise for applications in dielectric capacitors and supercapacitors.