Colossal electrocaloric effect in an interface-augmented ferroelectric polymer

Abstract

The electrocaloric effect demands the maximized degree of freedom (DOF) of polar domains and the lowest energy barrier to facilitate the transition of polarization. However, optimization of the DOF and energy barrier—including domain size, crystallinity, multiconformation coexistence, polar correlation, and other factors in bulk ferroelectrics—has reached a limit. We used organic crystal dimethylhexynediol (DMHD) as a three-dimensional sacrificial master to assemble polar conformations at the heterogeneous interface in poly(vinylidene fluoride)–based terpolymer. DMHD was evaporated, and the epitaxy-like process induced an ultrafinely distributed, multiconformation-coexisting polar interface exhibiting a giant conformational entropy. Under a low electric field, the interface-augmented terpolymer had a high entropy change of 100 J/(kg·K). This interface polarization strategy is generally applicable to dielectric capacitors, supercapacitors, and other related applications.

Influence of Stress on the Chiral Polarization and Elastrocaloric Effect in BaTiO3 with 180° Domain Structure

“…For ferroelectrics, the entropy change is given by ∆S = P 2 σ (T) − P 2 0 (T) /2ε 0 C. Then, the adiabatic temperature change in ferroelectrics can be determined as an expression of the polarization change. The parameter used in this work can be found in the literature [17,39,40].…”

“…Extensive research has been conducted on the study of the caloric impact in ferroelectric materials, specifically focusing on the electrocaloric and elastrocaloric effects. Those works are motivated by the possible use of these phenomena in solid-state refrigeration [39][40][41][42]. However, the detection of the Bloch polarization component in chiral ferroelectric materials presents a difficult task in experiments, leading to a restricted investigation of chiral polarization in the caloric effect of ferroelectric materials.…”

Observation of an Extensive Curie Temperature Window and Synergic Multicaloric Effects in NiMnCuGaSn Alloys

“…This shift necessitates the exploration of alternative cooling technologies that are entirely environmentally friendly. − Solid-state cooling based on the giant caloric effect upon the solid-state phase transformation of certain materials has garnered widespread interest, thanks to its zero-global-warming potential and high efficiency. Various caloric effects, including magnetocaloric effect, , electrocaloric effect, , elastocaloric effect, − and barocaloric effect, − corresponding to the magnetic field, electric field, uniaxial stress, and isostatic pressure, respectively, have been extensively explored in recent years. In between them, multicaloric materials that undergo a magnetostructural transformation could respond to more than one field, i.e., magnetic field and stress/pressure, providing a new pathway for solid-state refrigeration. , The coupling between spin and lattice in these materials enables more freedom of application/removing configurations of diverse fields (sequence, size).…”

Two Consecutive Negative Electrocaloric Peaks in <001>-Oriented PMN-30PT Single Crystals

“…These two works demonstrate the enormous application value of ferroelectric refrigeration, which sparked a research boom in the EC field. Since then, significant progress has been made in high-performance EC materials and ferroelectric refrigeration devices [6][7][8][9][10][11]. For example, Qian et al prepared a polarized high entropy polymer and achieved a significant giant EC effect with ∆S = 37.5 J kg −1 K −1 and ∆T = 7.5 K [11].…”