Polymer-based dielectric film capacitors are essential for ultrafast power conditioning but are constrained in low energy density. Here, we leverage surface interactions to enhance the breakdown strength of ultrathin (~15 – 100 nm) polymer films and effectively increasing their energy density. This phenomenon stems from van der Waal pinning effect where interfacial forces stabilize the polymer under high electric fields. Nonequilibrium chain conformations accentuate the pinning effect likely by improving surface adsorption of the chains. The pinning effects can be temperature stable if the polymer is crosslinked or surface grafted to the substrate. The ultrathin linear dielectric nanocapacitors exhibit low leakage current and achieved ~78 Joules per cubic centimeter with over 90% efficiency. These findings establish substrate interactions—rather than chemical composition alone—as a powerful design paradigm for engineering dielectrics that operate far beyond conventional material limits.

Critical points (CPs) in ferroelectrics are known for their association with giant dielectric and electromechanical responses, yet their structural origin, especially in nonrelaxor systems, remains unclear. We combine in situ biasing-heating transmission electron microscopy with first-principles-based simulations to map polarization disorder across the electric-field-temperature (E, T) phase diagram of single-crystal BaTiO3 (BTO). Near-CP conditions, Fourier-space analysis of high-resolution images shows diffuse broadening at the (001) point, suggesting randomized Ti off centering and local lattice distortion. Simulation reproduces and extends these trends: selected piezoelectric and dielectric coefficients peak along the ferroelectric phase boundary and its Widom-line continuation, while probability-density functions for unit cell dipoles broaden (higher disorder) near the CP and then narrow with increasing field (field-aligned ordering). This unified evidence identifies a disorder-driven enhancement of piezoelectricity in BTO near the CP and explains its decline in the supercritical regime. The results clarify the microscopic origin of the response maximum and suggest a practical route: tuning the disorderorder balance to maximize piezoelectric and other functional properties.

Polymer-based dielectric film capacitors are essential for high-power energy storage in applications such as electric vehicles, wearable electronics, and biomedical implants. 1-7 However, conventional polymer dielectrics are fundamentally limited by low energy density. 8,9 In this work, we demonstrate a strategy to enhance energy density in ultrathin polymer films (~15–100 nm) by exploiting surface interactions that stabilize the polymer under high electric fields. This enhancement arises from a van der Waals (vdW) pinning effect, in which interfacial forces constrain polymer chain motion and improve structural stability. Additionally, nonequilibrium chain conformations at the polymer–substrate interface is shown to further strengthen vdW pinning by increasing surface adsorption. By crosslinking or surface grafting, these pinning effects become thermally robust. The ultrathin linear dielectric nanocapacitors show low leakage current, achieving energy densities up to ~78 J/cm³ with over 90% efficiency. These findings establish substrate–polymer interactions, rather than chemical composition alone, as a powerful design paradigm for engineering high-performance polymer dielectrics, enabling energy storage capabilities beyond conventional limits and opening new pathways for next-generation electronic devices.

Li+ and Bi3+ (at 1:1 ratio) substitution of Pb2+ in the model compound PbZrO3 is investigated. It is found that [Pb1-x(Li1/2Bi1/2)(x)]ZrO3 ceramics remain phase pure of orthorhombic perovskite at x = 0.05, are almost phase pure at x = 0.10 and 0.15, and contain minor amounts of impurity phases at x = 0.20. The substitution allows the ceramics to be sintered to a high density at reduced temperatures, and at the same time, significantly enhances the dielectric breakdown strength. At 160 degrees C when reversible antiferroelectric (AFE)-ferroelectric (FE) phase transitions are observed in all compositions, the chemical substitution is shown to reduce the electric hysteresis, increase the energy storage density, and improve the energy efficiency. The results will help design future high-performance ceramics for energy storage capacitors. It is further observed that the (Li1/2Bi1/2) substitution of Pb in PbZrO3 weakly impacts the dielectric behavior of the ceramics: The temperature at dielectric maximum, T-m, varies within a narrow range of 232.4-237.6 degrees C; the relaxation parameter in the paraelectric phase, gamma, stays close to unity and barely changes; and the diffuseness parameter of the phase transition at T-m, d, remains low. Defect dipoles of Li-Pb(')-Bi-Pb(center dot) preferably along < 1 1 0 > directions are proposed to explain the un-disrupted long-range AFE order in the [Pb1-x(Li1/2Bi1/2)(x)]ZrO3 ceramics.

PbZrO3-based antiferroelectric (AFE) ceramics are promising dielectrics for high-energy-density capacitors due to their reversible phase transitions during charge–discharge cycles. In this work, a new composition series, [Pb[Formula: see text]La[Formula: see text](Li[Formula: see text]Bi[Formula: see text]Sr[Formula: see text]][Zr[Formula: see text]Sn[Formula: see text]Ti[Formula: see text]]O3, with Li[Formula: see text] and Bi[Formula: see text] substitution of Pb[Formula: see text] at [Formula: see text], 0.04, 0.08, 0.12, 0.16 is investigated for the microstructure evolution, ferroelectric (FE) and dielectric properties. It is found that Li[Formula: see text] and Bi[Formula: see text] substitution can significantly reduce the sintering temperature and simultaneously enhance the dielectric breakdown strength. An ultrahigh energy efficiency (94.0%) and a large energy density (3.22[Formula: see text]J/cm[Formula: see text] are achieved in the composition of [Formula: see text] with a low sintering temperature (1075∘C).

Antiferroelectric (Pb0.87Sr0.05Ba0.05La0.02)(Zr0.52Sn0.40Ti0.08)O-3 thin film capacitors were fabricated for dielectric energy storage. Thin films with excellent crystal quality (FWHM 0.021 degrees) were prepared on (100) SrRuO3/SrTiO3 substrates by pulsed laser deposition. The out-of-plane lattice constant of the thin film was 4.110 +/- 0.001 & Aring;. An average maximum recoverable energy storage density, 88 +/- 17 J cm(-3) with an efficiency of 85% +/- 6% at 1 kHz and 80 +/- 15 J cm(-3) with an efficiency of 91% +/- 4% at 10 kHz, was achieved at room temperature. The capacitor was fatigue resistant up to 106 cycles at an applied electric field of 2 MV cm(-1). These properties are linked to a low level of hysteresis and slow polarization saturation. PbZrO3-derived oxide thin film capacitors are promising for high efficiency and low loss dielectric energy storage applications.

PbZrO3-based antiferroelectric (AFE) ceramics are promising dielectrics for high-energy-density capacitors due to their reversible phase transitions during charge–discharge cycles. In this work, a new composition series, [Pb[Formula: see text]La[Formula: see text](Li[Formula: see text]Bi[Formula: see text]Sr[Formula: see text]][Zr[Formula: see text]Sn[Formula: see text]Ti[Formula: see text]]O3, with Li[Formula: see text] and Bi[Formula: see text] substitution of Pb[Formula: see text] at [Formula: see text], 0.04, 0.08, 0.12, 0.16 is investigated for the microstructure evolution, ferroelectric (FE) and dielectric properties. It is found that Li[Formula: see text] and Bi[Formula: see text] substitution can significantly reduce the sintering temperature and simultaneously enhance the dielectric breakdown strength. An ultrahigh energy efficiency (94.0%) and a large energy density (3.22[Formula: see text]J/cm[Formula: see text] are achieved in the composition of [Formula: see text] with a low sintering temperature (1075∘C).

Precipitates have been shown to harden bulk piezoelectric ceramics, manifested as their increased mechanical quality factor. In this work with a model system (Ba,Ca)TiO3, we analyze the morphologies of CaTiO3-rich precipitates and their impacts on the microstructures in their surrounding BaTiO3-rich matrix. Also, the response of ferroelectric domains around CaTiO3-rich precipitates during heating and cooling is observed in situ with transmission electron microscopy. Domains attached to precipitates are observed remaining unchanged up to the Curie point at which they disappear. During cooling, domains are observed to form in the vicinity of precipitates and being held in place down to room temperature. Both observations corroborate previous findings that precipitates act as domain-pinning points, behaving in a similar manner to earlier experiments with electrical field biasing. Dislocations are often seen around precipitates in the matrix grain and are observed interfering with domains during heating cycles. Dislocations may provide an additional mechanism to restrict domain wall motion and offer a greater piezoelectric hardening effect.

Precipitates have recently been found to significantly enhance the mechanical quality factor in piezoelectric ceramics. Such a piezoelectric hardening effect was attributed to strong interactions between ferroelectric domains and precipitates. In the present work, the response of domains to applied electric fields is observed in situ via transmission electron microscopy in aged (Ba, Ca)TiO3 ceramics with precipitates to reveal the underlying mechanism of this phenomenon. Ferroelectric domains in the Ba-rich matrix grain are observed to be more concentrated near non-polar Ca-rich precipitates. With increasing applied voltage, domains separate from precipitates merge together first, while those near precipitates persist to higher voltages. During ramping down, domains nucleate from precipitates. These direct observations confirm the strong interactions between ferroelectric domains and precipitates in piezoelectric ceramics.

Antiferroelectric ceramics, via the electric-field-induced antiferroelectric (AFE)-ferroelectric (FE) phase transitions, show great promise for high-energy-density capacitors. Yet, currently, only 70-80% energy release is found during a charge-discharge cycle. Here, for PbZrO3-based oxides, geometric nonlinear theory of martensitic phase transitions is applied (first used to guide supercompatible shape-memory alloys) to predict the reversibility of the AFE-FE transition by using density-functional theory to assess AFE/FE interfacial lattice-mismatch strain that assures ultralow electric hysteresis and extended fatigue lifetime. A good correlation of mismatch strain with electric hysteresis, hence, with energy efficiency of AFE capacitors is observed. Guided by theory, high-throughput material search is conducted and AFE compositions with a near-perfect charge-discharge energy efficiency (98.2%), i.e., near-zero hysteresis are discovered. And the fatigue life of the capacitor reaches 79.5 million charge-discharge cycles, a factor of 80 enhancement over AFE ceramics with large electric hysteresis.

The lack of materials that can function reliably under extreme electric fields is a critical roadblock to achieving higher energy efficiency and extended service lifetime of devices in electricity generation, transmission, and consumption. Materials typically fail at two or three orders of magnitude below their theoretical dielectric breakdown strength. Identifying the origins of premature dielectric breakdown using state-of-the-art characterization tools will, therefore, enable the design and discovery of transformational materials capable of approaching their intrinsic limits. The vast improvement in the resolution power of imaging tools, combined with the recently developed in situ electric biasing technique, has made high resolution observations of dielectric breakdown as it happens possible. The overall goal of the project is to directly image the dynamic processes of defect formation, accumulation, and interaction with preexisting defects (e.g., dislocations, domain walls, and grain boundaries in crystalline dielectric films) under electric fields up to 1,000 MV/m with a temporal resolution better than 5 microseconds. Using the newly acquired, custom-made Hysitron PI95 transmission electron microscopy (TEM) specimen holder, in situ TEM observations of breakdown at the sub nanometer resolution will be made on representative dielectric compounds with progressive complexities: the linear dielectric SiO2, CuO, and TiO2, the ferroelectric BaTiO3 nanocrystals and nanocubes. Through direct observation of the breakdown event at high spatial and temporal resolutions, the nanoscale mechanisms for the failure of dielectrics under intense electric fields will be identified. The results of the project will be applied to the design and processing of new dielectric materials with higher efficiency, improved reliability, and a prolonged lifetime. Such new dielectrics are urgently needed for modernizing energy infrastructures.

Hierarchical domain structures associated with oxygen octahedra tilting patterns were observed in lead-free (Bi 1/2 Na 1/2 )TiO 3 ceramics using aberration-corrected high-resolution transmission electron microscopy (HRTEM). Three types of domains are induced by distinct mechanisms: the ‘orientation-domain’ is induced at micrometer scale formed by different tilting orientations of the oxygen octahedra, the ‘meso-chemical-domain’ occurs at a few tens of nanometer scale by chemical composition variation on the A-site in the ABO 3 perovskite structure, and the ‘nano-cluster-region’ runs across several unit-cells with apparent A-site cation segregation with oxygen vacancies clustering around Na cations. Based on HRTEM amplitude contrast imaging (ACI), the correlation between the oxygen octahedral tilting pattern and compositional non-stoichiometry was established. The role of the hierarchical domain structure associated with the tilting patterns of the oxygen octahedra on the ferroelectric behavior of (Bi 1/2 Na 1/2 )TiO 3 is also discussed.

High-power piezoelectric applications are predicted to share approximately one-third of the lead-free piezoelectric ceramic market in 2024 with alkaline niobates as the primary competitor. To suppress self-heating in high-power devices due to mechanical loss when driven by large electric fields, piezoelectric hardening to restrict domain wall motion is required. In the present work, highly effective piezoelectric hardening via coherent plate-like precipitates in a model system of the (Li,Na)NbO3 (LNN) solid solution delivers a reduction in losses, quantified as an electromechanical quality factor, by a factor of ten. Various thermal aging schemes are demonstrated to control the average size, number density, and location of the precipitates. The established properties are correlated with a detailed determination of short- and long-range atomic structure by X-ray diffraction and pair distribution function analysis, respectively, as well as microstructure determined by transmission electron microscopy. The impact of microstructure with precipitates on both small- and large-field properties is also established. These results pave the way to implement precipitate hardening in piezoelectric materials, analogous to precipitate hardening in metals, broadening their use cases in applications.

Ceramic composites of (1-x)Pb-0.99{Nb-0.02[(Zr0.57Sn0.43)(0.937)Ti-0.063](0.98)}O-3 (PNZST)/xZnO were recently reported to exhibit exceptionally high pyroelectric coefficients near human body temperature due to the ferroelectric-antiferroelectric transition of the matrix grains. In the present work, a comparative study is conducted on two composites of x = 0.1 and 0.4 with in situ heating transmission electron microscopy (TEM). The results verify the presence of strain field in the PNZST grain adjacent to a ZnO particle and the stabilized ferroelectric phase at room temperature in the composite of x = 0.1. During heating, the ferroelectric matrix grain transforms to the antiferroelectric phase, contributing to the pyroelectric effect. In the composite of x = 0.4, high-angle annular dark-field imaging combined with energy-dispersive X-ray spectroscopy reveal the existence of both ZnO and Zn2SnO4. The formation of Zn2SnO4 indicates that Sn in the PNZST matrix grain is selectively extracted, and decomposition of the perovskite phase has taken place. The decomposition products in the form of fine particles are observed to facilitate the nucleation of the antiferroelectric phase and restrict the motion of the phase boundary during heating. The larger amount of ZnO and Zn2SnO4 and the decomposition of the PNZST perovskite phase are suggested to be responsible for the much lower pyroelectric coefficient in the x = 0.4 composite.

Dislocations are usually expected to degrade electrical, thermal and optical functionality and to tune mechanical properties of materials. Here, we demonstrate a general framework for the control of dislocation-domain wall interactions in ferroics, employing an imprinted dislocation network. Anisotropic dielectric and electromechanical properties are engineered in barium titanate crystals via well-controlled line-plane relationships, culminating in extraordinary and stable large-signal dielectric permittivity (≈23100) and piezoelectric coefficient (≈2470 pm V-1). In contrast, a related increase in properties utilizing point-plane relation prompts a dramatic cyclic degradation. Observed dielectric and piezoelectric properties are rationalized using transmission electron microscopy and time- and cycle-dependent nuclear magnetic resonance paired with X-ray diffraction. Succinct mechanistic understanding is provided by phase-field simulations and driving force calculations of the described dislocation-domain wall interactions. Our 1D-2D defect approach offers a fertile ground for tailoring functionality in a wide range of functional material systems.

The fatigue behavior of antiferroelectric ceramics with different electric hysteresis are comparatively studied. The ceramic with small hysteresis displays not only a high energy efficiency, but also a much more stable performance and longer life.

Domain wall motion in ferroics, similar to dislocation motion in metals, can be tuned by well‐concepted microstructural elements. In demanding high‐power applications of piezoelectric materials, the domain wall motion is considered as a lossy hysteretic mechanism that should be restricted. Current applications for so‐called hard piezoelectrics are abundant and hinge on the use of an acceptor‐doping scheme. However, this mechanism features severe limitations due to enhanced mobility of oxygen vacancies at moderate temperatures. By analogy with metal technology, the authors present here a new solution for electroceramics, where precipitates are utilized to pin domain walls and improve piezoelectric properties. Through a sequence of sintering, nucleation, and precipitate growth, intragranular precipitates leading to a fine domain structure are developed as shown by transmission electron microscopy, piezoresponse force microscopy, and phase‐field simulation. This structure impedes the domain wall motion as elucidated by electromechanical characterization. As a result, the mechanical quality factor is increased by ≈50% and the hysteresis in electrostrain is suppressed considerably. This is even achieved with slightly increased piezoelectric coefficient and electromechanical coupling factor. This novel process can be smoothly implemented in industrial production processes and is accessible to simple laboratory experimentation for microstructure optimization and implementation in various ferroelectric systems.

We report on the measurement of the electrical properties of individual pristine and doped BaTiO3 nanocubes by using in situ transmission electron microscopy with a two-electrode configuration. The dimensions of the nanocubes tested are between 10 and 20 nm, which rendered their in situ electrical characterization challenging. We characterized 4%Cr and 5%La (atomic percentage) doped BaTiO3 nanocubes and compared them with the properties of pristine BaTiO3 nanocubes synthesized by the same solvothermal method. We found that the resistance of all three types of nanocubes when displayed in log-scale shows a nearly linear dependence on the applied electric field (R2 ≥ 0.95) over a wide range of electric fields (50–900 kV/cm). Compared with pristine BaTiO3 nanocubes, the resistance of both 4%Cr and 5%La doped nanocubes showed reduced variation rates with respect to the electric field, with 5%La doping, demonstrating a better reduction in the variation rate. By developing techniques capable of evaluating the properties of individual BaTiO3 nanocubes, we expect that our work to open the door to the use of BaTiO3 nanomaterials in the design of future multilayer ceramic capacitors with improved volumetric efficiency and ferroelectrics-enabled nanodevices with advanced functionality.

Defects are essential to engineering the properties of functional materials ranging from semiconductors and superconductors to ferroics. Whereas point defects have been widely exploited, dislocations are commonly viewed as problematic for functional materials and not as a microstructural tool. We developed a method for mechanically imprinting dislocation networks that favorably skew the domain structure in bulk ferroelectrics and thereby tame the large switching polarization and make it available for functional harvesting. The resulting microstructure yields a strong mechanical restoring force to revert electric field-induced domain wall displacement on the macroscopic level and high pinning force on the local level. This induces a giant increase of the dielectric and electromechanical response at intermediate electric fields in barium titanate [electric field-dependent permittivity (ε33) ≈ 5800 and large-signal piezoelectric coefficient (d 33*) ≈ 1890 picometers/volt]. Dislocation-based anisotropy delivers a different suite of tools with which to tailor functional materials.