Ultrahigh capacitive energy density in ion-bombarded relaxor ferroelectric films

Abstract

<jats:p>Dielectric capacitors can store and release electric energy at ultrafast rates and are extensively studied for applications in electronics and electric power systems. Among various candidates, thin films based on relaxor ferroelectrics, a special kind of ferroelectric with nanometer-sized domains, have attracted special attention because of their high energy densities and efficiencies. We show that high-energy ion bombardment improves the energy storage performance of relaxor ferroelectric thin films. Intrinsic point defects created by ion bombardment reduce leakage, delay low-field polarization saturation, enhance high-field polarizability, and improve breakdown strength. We demonstrate energy storage densities as high as ~133 joules per cubic centimeter with efficiencies exceeding 75%. Deterministic control of defects by means of postsynthesis processing methods such as ion bombardment can be used to overcome the trade-off between high polarizability and breakdown strength.</jats:p>

Dielectric films for high performance capacitive energy storage: multiscale engineering

“…50 However, this is at the sacrifice of fabrication efficiency. A "layer-by-layer" deposition (LLD) strategy was proposed recently, which combines (1) [17][18][19][20][21][22][23][24][25][27][28][29][30][31][32][33][34][35][36][37][38] quencies (e.g. ∼50 Hz) to form a monolayer (unit-cell thick) in 10-20 ms, and (2) a long interval (>1 s) for full relaxation and reconstruction of the monolayer towards stable structure (Fig.…”

“…Besides element doping, extrinsic strategies such as tuning deposition parameters 58 and ion irradiation 59 can also introduce defect complexes. A highenergy helium ion bombardment strategy was reported recently, 37 which knocks ions from their lattice sites in 0.68Pb (Mg 1/3 Nb 2/3 )O 3 -0.32PbTiO 3 (PMN-PT) films, causing deepenergy-level defect complexes, e.g., V′…”

“…31,32 The high E b , together with the high permittivity ( polarization) maintained in dielectric films, gives rise to ultrahigh U e of over 100 J cm −3 . [33][34][35][36][37][38] In addition, dielectric films are favourable for their moderate working voltage (dozens to hundreds of volts), matching the commonly used power voltage; they are also more utilizable in embedded integrated circuits with scaled-down geometry.…”

Relaxor Ferroelectric Polymers: Insight into High Electrical Energy Storage Properties from a Molecular Perspective

“…[ 3–6 ] Different from normal ferroelectrics with long‐range ferroelectric orders, relaxor ferroelectrics are macroscopically paraelectric with no spontaneous polarization at zero electric field, which leads to a very slim polarization–electric field ( P – E ) hysteresis loop with nearly zero remnant polarization. [ 7–9 ] Relaxor ferroelectric terpolymers P(VDF‐TrFE‐CFE) and P(VDF‐TrFE‐CTFE) (VDF: vinylidene fluoride; TrFE: trifluoroethylene; CFE: 1,1‐chlorofluoroethylene; CTFE: chlorotrifluoroethylene) exhibit the highest room‐temperature dielectric constants (>50 at 1 kHz) among the known polymers. [ 7,10–13 ] The elimination of large polarization hysteresis in P(VDF‐TrFE‐CFE) (58.3/34.2/7.5 mol%) terpolymer in comparison to a typical rectangle hysteresis loop of normal ferroelectric P(VDF‐TrFE) yields a much higher electric energy density with substantially reduced loss.…”

Improving Dielectric Constant of Polymers through Liquid Electrolyte Inclusion

“…Polymer dielectrics, benefiting from their easy processing, lightweight and good flexibility, have generated significant academic and industrial interest for several decades, and have promoted multiple modern technologies such as energy storage systems, [ 1–4 ] flexible electronics, [ 5–9 ] electroactive soft robotics, [ 10–17 ] Generally, dielectric constant of pure polymers is intrinsically low (usually 2–5). Compositing with inorganic fillers, for example, conductive carbons, high‐k ceramics, metal micro‐/nanoparticles is practical for increasing the dielectric constant.…”