Dielectric Capacitors Research Articles

Preparation and investigation of structural, optical, and dielectric properties of PVA/PVP blend films boosted by MWCNTs/AuNPs for dielectric capacitor applications

With the rising global energy demands, there is a pressing need for the invention of efficient and reliable energy storage systems. This research centers on the creation and analysis of flexible dielectric capacitors composed of polymer nanocomposites (PNCs), incorporating a blend of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) as the base polymer, with multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) serving as nanofillers. The AuNPs were produced through an environmentally friendly synthesis method. Films made from PVA/PVP blended with MWCNTs and AuNPs were fabricated using the casting approach. Various characterization methods, including TEM, XRD, FTIR, and UV–Vis spectroscopy, were utilized to evaluate the samples. A detailed analysis of their electrical/dielectric characteristics was conducted. XRD analysis revealed a significant decrease in crystallinity from 55% for the pure PVA/PVP blend to 37% for the 1.6 wt% nanofiller composite, indicating increased amorphous content, which facilitates better ion mobility. FTIR confirmed strong interactions between the polymer matrix and nanofillers, with intensified vibrational peaks pointing to enhanced molecular dynamics. UV–Vis spectroscopy demonstrated a red shift in the absorption edge, and Tauc plot analysis showed a reduction in the indirect/direct optical band gap from 4.84 eV/5.68 eV for the pure blend to 4.26/5.35 eV for the nanocomposite with 1.6 wt% nanofillers. The addition of nanofillers resulted in improvements in their dielectric features, which exhibited a significant performance improvement, with the dielectric constant (ε′) reaching approximately 1100 at low frequency for the 1.6 wt% nanofiller sample, compared to 9 for the pure blend. Additionally, the dielectric loss (ε'') and tangent loss (tan δ) were reduced, with tan δ showing a decrease from 15 for the pure blend to 2 for the 1.6 wt% nanofiller composite at low frequency, indicating enhanced dielectric efficiency and reduced energy dissipation. The capacitors' functionality was assessed through capacitance-frequency and conductance-frequency analyses. The capacitors exhibited stable high capacitance across a broad frequency spectrum, making them alternatives for energy storage solutions.

Realizing Ultrahigh Energy Storage Density in (Bi0.5Na0.5)0.94Ba0.06TiO3-Based Ceramics via Manipulating the Domain Configuration and Grain Boundary Density.

Dielectric capacitors with a high power density are widely used in various pulsed power electronic systems. However, their low comprehensive energy storage performance severely limits the development of these systems in terms of miniaturization and lightweight design. Herein, we achieved decent energy storage performance in a class of (Bi0.5Na0.5)0.94Ba0.06TiO3 (BNTBT)-based ceramics by synergistically manipulating domain configurations and grain boundary densities. High-resolution transmission electron microscopy and piezoresponse force microscopy confirm that composition-driven refined domain configurations with weak polarity effectively improve the polarization response of BNTBT-based ceramics. The results of experimental and phase-field simulation analysis indicate that the refined grain size contributes to its high breakdown electric strength (Eb). Benefiting from the high polarization difference (ΔP) of 32.62 μC/cm2, delayed saturation polarization behavior, and an ultrahigh Eb of 815.00 kV/cm, BNT-based ceramics simultaneously achieve a high energy storage density (Wrec) of ∼12.25 J/cm3 and an efficiency (η) of ∼86.90%. Because of these structure-induced advantages, the ceramics also exhibit good energy storage temperature stability in the range of 30-150 °C. We believe that the findings of this work may provide practical guidance for the development of high-performance energy storage ceramics.

An Antiferroelectric‐Coated Metal Foam Infiltrated with Liquid Metal as a Dielectric Capacitor

Nickel metal foams serve as both a substrate and bottom electrode for a dielectric capacitor using atomic‐layer deposition (ALD) and a eutectic gallium–indium (EGaIn) liquid metal (LQM) counter electrode. The conformal dielectric has a composition of 6.25% Al–HfO2 in the antiferroelectric phase, confirmed with polarization versus electric field measurements. Liquid EGaIn is pressure‐infiltrated within the coated foams to form the dielectric capacitor. Capacitances up to 4 μF are realized. Calorimetry of the infiltrated capacitor shows a 60 J g−1 latent heat upon melting a frozen EGaIn electrode, suggesting that the phase change can alleviate thermal deviations from pulsed power capacitor operation. Infiltrated capacitors are also shown to survive bending and freeze–thaw cycles. The metal foam–ALD dielectric–LQM capacitor shows a combined set of thermal and electrical properties not available in other classes of capacitors.

Effect of grain size and grain boundary on the energy storage performance of polycrystalline ferroelectrics

Dielectric capacitors based on polycrystalline ferroelectrics have attracted much attention due to their significant power density and fast charge–discharge speed. The energy storage performance of polycrystalline ferroelectrics is highly dependent on the grain size and grain boundary. Here, the effect of grain size and grain boundary on the domain structures and polarization–electric field (P–E) hysteresis loops of polycrystalline ferroelectrics are investigated by using a phase-field model based on the time dependent Ginzburg–Landau (TDGL) equation. It is found that the depolarization field in the grain boundary induces the vortex domain when the grain size is reduced or the grain boundary thickness increases in certain extent, resulting in slender P–E loops, which contributes to an improvement in the energy storage efficiency and density. However, as the grain size further decreases or the grain boundary thickness further increases, the energy storage density decreases, which is attributed to the concurrent reduction in both the remnant and saturation polarizations. This study provides a considerable insight for optimizing the energy storage performance by carefully adjusting the grain size and grain boundary thickness in polycrystalline ferroelectrics.

Optimized energy storage performances via high-entropy design in KNN-based relaxor ferroelectric ceramics

Dielectric capacitors play an irreplaceable role in complex and integrated electronic systems. However, attaining ultrahigh recoverable energy storage density (Wrec) alongside energy storage efficiency (η) poses a formidable challenge, impeding the advance towards the miniaturization and integration of cutting-edge energy storage devices. In this work, a high-entropy strategy with a viscous polymer process is adopted, bringing about ultrafine grains and polar nanoregions (PNRs) accompanied by enhanced electrical homogeneity and polarization relaxation characteristics. As a result, an ultrahigh Wrec ∼ 7.51 J/cm3 is achieved in a high-entropy KNN-based energy storage ceramic with a high η ∼ 88.4% at 750 kV/cm. Moreover, the ceramic capacitor exhibits a colossal power density reaching approximately 420 MW/cm3 and a discharge energy density of approximately 4.85 J/cm3 at 160 ℃. Impressively, it maintains low variation rates of less than 4% across a broad temperature range from 20 ℃ to 160 ℃. The new approach opens avenues for the design and development of superior dielectric materials used in next-generation high-power pulse devices.

Energy storage performance of sandwich structure dielectric composite by BNNS/TiO2 Co-doping for the high electric field capacitor

Dielectric capacitors are crucial for power systems and hybrid vehicles. However, the polymer dielectric owns low energy density and cannot meet the demands of high-power and energy storage systems. The synergistic improvement of balance between dielectric constant (εr) and breakdowon field strength (Eb), along with better energy storage performance, is a primary focus of this study. This research employs a high εr of P(VDF-TrFE-CFE) blended with linear PMMA to create a sandwich-structured composite via high-speed electrostatic spinning. Boron Nitride Nanosheets (BNNSs) for insulation and TiO2 for polarization are used as fillers, aiming to achieve polymer-based composite with large energy storage density and minimal energy loss. Results show that the sandwich-structured composite with 0.5 vol.% BNNSs in outer layer and 3 wt.% TiO2 in middle layer achieves the largest Ue of 21.8 J/cm3 at the η of 74 %. This study broadens the application of novel dielectric materials in the fields of energy.

Achieving ultra-high energy storage performance in simple systems through minimal element substitution

Dielectric capacitors are essential components of modern advanced electronic devices and power systems based on their ultra-fast charging and discharging speeds and supreme power densities. Nevertheless, how to comprehensively boost their energy storage density and storage efficiency is still an insurmountable challenge. Here, we report a simple micro-chemical polarizability modulation strategy that enables SrTiO3-based dielectric materials to achieve excellent energy storage properties. The energy density and energy efficiency are increased to as high as 76 J∙cm−3 and 72 % from 0.4 J∙cm−3 and 46.7 % of pure STO, respectively, which is the largest value in micro-substitution (less than 3 %). Our results show that the introduction of trace amounts of elements with high ionic polarizabilities (Mn, V) facilitates the increase of chemical disorder and the formation of stable and highly dynamic polar nanoregions (PNRs), which reduces the hysteresis of the polarization switching and improves the polarization at the breakdown field strength, synergistically fostering the energy storage performance. The results of X-ray photoelectron spectroscopy and scanning electron microscopy reveal that the micro-substitution of Mn and V promote the reduction of oxygen vacancies and grain size, improving the breakdown resistance and stability of the capacitor. This present approach is expected to be widely used in the development of high-performance dielectrics.

High energy storage performance in SrZrO3-modified quaternary relaxor ferroelectric ceramics

Lead-free relaxor ferroelectric ceramics have attracted much attention in pulse power systems owing to their excellent energy storage performance and environmentally friendly characteristics. However, it is challenging to simultaneously achieve high energy storage density and efficiency in ferroelectric ceramics for practical applications. Herein, a novel optimization strategy is designed by introducing a linear dielectric SrZrO3 (SZ) with wide bandgap (Eg) into the BaTiO3-Bi0.5Na0.5TiO3-NaNbO3 (BT-BNT-NN) to form quaternary ceramics, disrupting long-range ferroelectric ordering and constructing weakly coupled polar nanoregions (PNRs). As a result, the recoverable energy density (Wrec) and energy storage efficiency (η) are simultaneously improved in (1-x) (BT-BNT-NN)-xSZ ceramics. At an electric field of 530 kV/cm, a Wrec of 3.37 J/cm3 and an η of 82.5 % were optimally achieved at x = 0.16 due to the formation of slim P-E loops, delayed polarization saturation, and ultra-high breakdown field strength (Eb), where the improvement of Eb is attributed to the reduction of porosity and the increase of Eg. Furthermore, the as-fabricated samples also exhibit excellent frequency and temperature stability. This study provides an effective method for developing high-performance dielectric capacitors for energy storage applications.

Preparation of two–dimensional gradient fillers reinforced polymer nanocomposites for high–performance energy storage of dielectric capacitors

The serious interfacial issue between the inorganic filler and the organic matrix in the dielectric nanocomposite results in a low electric field breakdown strength (Eb) and low energy density (Ue). In this work, novel KxNa1–xNbO3@ZrO2 (KNN@ZO) nanosheets (NSs) were prepared by coating highly insulated ZO on the ferroelectric two–dimensional (2D) KNN NSs via a chemical precipitation method. As fillers, the KNN@ZO significantly improved the energy storage performances of poly (vinylidene fluoride) (PVDF)–polymethyl methacrylate (PMMA) blends. The highly insulated ZO shell restricts the carrier migration at the filler/polymer interface, thereby reducing the local electric field distortion. By sandwich structural design, a high Ue of 19.8 J/cm3, with a large difference of electrical displacement (8.5 μC/cm2), is measured in KNN@ZO/PVDF–PMMA with 5 % filler content at 528 MV/m. According to the finite element simulation, the 2D morphology and gradient structure can enhance the electric field distribution, and therefore effectively increase the Eb of nanocomposites. The results indicate that the 2D core–shell NSs fillers with gradient dielectric constant represent an effective approach to improve energy storage performance of the polymer–based nanocomposites.

Enhancing energy storage performance of dielectric capacitors: Tailoring CaO-SrO-Na2O-Nb2O5-SiO2 glass-ceramics through controlled crystallization for pulse power applications

As potential dielectric materials for capacitors, glass-ceramics exhibit significant promise in the realm of pulse power supply. Extensive research has been undertaken to explore the commendable voltage resistance and favorable dielectric properties of glass-ceramics. They exhibit a rapid charge and discharge rate. However, the limited energy storage density of glass-ceramics constrains their practical application. In this study, we focused on the preparation of CaO-SrO-Na2O-Nb2O5-SiO2(CSNNS) glass-ceramics through conventional melting and high-temperature crystallization processes. Our investigation delved into the impact of crystallization temperature on the phase composition, dielectric properties, and energy storage characteristics of the CSNNS glass-ceramics. The results indicate a direct correlation between the dielectric constant and dielectric loss, both exhibiting an upward trend with increasing crystallization temperature. Simultaneously, the microstructure of the glass-ceramics manifests signs of deterioration, characterized by larger grain size and heightened porosity, leading to a reduction in breakdown strength. At a crystallization temperature of 1100 °C, the CSNNS glass-ceramics demonstrated a remarkable combination of a high dielectric constant (∼280) and superior breakdown strength (481 kV/cm). The achieved maximum theoretical energy storage density reached 2.87 J/cm3. At an electric field of 100 kV/cm, the effective energy storage density is 0.23 J/cm3, and the energy storage efficiency is 72 %. These findings demonstrate the broad application potential of the CSNNS glass-ceramics in the domain of pulse power, highlighting their relevance for future developments in this field.

Effect of strain gradient and interface engineering on the high-temperature energy storage capacitors

The miniaturization and high integration of electronic devices pose new requirements for the energy storage density and high-temperature performance of dielectric capacitors. For thin film materials, internal stress and the interface layer often show a significant impact on their energy storage performance. Therefore, the capacitors with different stress gradient sequences and different periods were designed by BaHf0.17Ti0.83O3 (BHTO17), BaHf0.25Ti0.75O3 (BHTO25), and BaHf0.32Ti0.68O3 (BHTO32) to investigate the effect of stress gradient and interface engineering on the energy storage characteristics. Dielectric thin film structures with upward gradient, downward gradient, and periodic upward gradient (4N) were constructed. The study found that the upward gradient structure had higher breakdown field strength than the downward gradient structure. This is because the upward gradient structure can effectively extend the ending electric field of the Ohmic conduction mechanism and delay the activation electric field of the F–N tunneling mechanism. The 4N structure had a slightly higher breakdown field strength (reaching 9.22 MV/cm) compared to the pure upward gradient structure. The 4N structure thin film also exhibited higher energy storage density (115.44 J/cm3) and wide temperature (−100 to 400 °C) characteristics. These findings provide important guidance and application value for improving the energy storage characteristics of dielectric capacitors at high temperatures through structural design.

Synergistic optimization of delayed polarization saturation and enhanced breakdown strength in lead-free capacitors for superior energy storage characteristics

High-performance dielectric energy-storage ceramics are indispensable core components in pulsed power systems. Despite progress in enhancing energy storage performance, there are still significant constraints among various macroscopic performance parameters, hindering their miniaturization and integration into devices. Herein, we propose a novel weakly coupled relaxor ferroelectric ceramic system that delays premature polarization saturation of BaTiO3-based ceramics to achieve the desirable energy storage characteristics. The ceramic exhibits a high energy storage density (Wrec) of ∼4.58 J cm−3 and high energy efficiency (η) of ∼95.2 % under an electric field of 540 kV cm−1, along with good performance stability in the range of 40–160 °C and 1–120 Hz. Furthermore, the enhanced insulation properties and refined average grain size contribute to the high breakdown field strength (Eb) of the system. These findings provide a viable framework for the design of dielectric ceramic capacitors with high energy-storage characteristics.

Simultaneous Improvement of Energy Storage Characteristics and Temperature Stability in K0.5Na0.5NbO3-Based Ceramics via LiF Modification.

The splendid energy storage performances with eminent stability of dielectric ceramics utilized in pulsed power devices have been paid more attention by researchers. This scheme can be basically realized through introducing Li+, Bi(Mg2/3Ta1/3)O3, NaNbO3, and LiF into KNN-based ceramics. Under the breakdown strength (BDS) of 460 kV/cm, an outstanding energy storage density (W) of 6.05 J/cm3 with a high energy efficiency (η) of 85.9% is implemented. Within the broad temperature range from 20 to 140 °C, the numerical fluctuations of energy storage characteristics can be maintained at a relatively stable level (ΔWrec ≈ 3.5%, Δη ≈ 2.8%). As for the charging-discharging performances, this component possesses a fast discharging speed (t0.90 ≈ 51 ns) and remarkable temperature stability (the variations are smaller than 3.5%). Additionally, the internal mechanisms of outstanding energy storage properties can be confirmed via crystal structures and domain structures, the content of oxygen vacancies, dielectric and impedance spectra, and phase simulation. Hence, the combination of outstanding energy storage with remarkable thermal stability can be fulfilled in one ceramic system according to this discovery, providing a research thought of developing the materials for dielectric capacitors.

Stable energy storage performance of introduced PI-PESU dielectric composite serving at the high electric and thermal fields with the designed layer structure

Excellent energy storage performance of dielectric capacitor is critical in modern electronic devices and power systems. However, the key component of dielectric composite may fail to function properly under severe service conditions, such as elevated temperature and great applied electric field. Here, the linear dielectrics of PI and PESU with high glass transition temperature (Tg) were proposed to improve the energy storage performance of composite, which hold the weakened carrier migration. The large band-gap of PESU and tight molecular chain of PI are beneficial for reducing leakage current density of composite, enhancing inter-molecular stability over a wide temperature and electric field range. Finally, the energy storage performance is improved by constructing a multi-layer structure with alternating outer layers. For instance, the discharge energy density (Ue) of 0.4PI-0.6PESU composite reaches 6.38 J/cm3 at 700 kV/mm and 80 °C. Significantly, the Ue of multi-layer 2/1/PVDF/1/2 composite is increased by 92.36 % at 80 °C and 400 kV/mm (from 2.88 J/cm3 to 5.54 J/cm3), and the efficiency (η) of it keeps at 68.5 %. Meanwhile, it owns a good cycle stability after 50,000 cycles with η > 90 %. This work provides a new direction of developing dielectric composite serving in severe service conditions for capacitors.

Polymer Capacitor Films with Nanoscale Coatings for Dielectric Energy Storage: A Review

Enhancing the energy storage properties of dielectric polymer capacitor films through composite materials has gained widespread recognition. Among the various strategies for improving dielectric materials, nanoscale coatings that create structurally controlled multiphase polymeric films have shown great promise. This approach has garnered considerable attention in recent years due to its effectiveness. This review examines surface-coated polymer composites used for dielectric energy storage, discussing their dielectric properties, behaviors, and the underlying physical mechanisms involved in energy storage. The review thoroughly examines the fabrication methods for nanoscale coatings and the selection of coating materials. It also explores the latest advancements in the rational design and control of interfaces in organic–inorganic, organic–organic, and heterogeneous multiphase structures. Additionally, the review delves into the structure–property relationships between different interfacial phases and various interface structures, analyzing how nanoscale coatings the impact dielectric constant, breakdown strength, conduction and charge transport mechanisms, energy density and efficiency, thermal stability, and electrothermal durability of polymeric capacitor films. Moreover, the review summarizes relevant simulation methods and offers computational insights. The potential practical applications and characteristics of such nanoscale coating techniques are discussed, along with the existing challenges and practical limitations. Finally, the review concludes with a summary and outlook, highlighting potential research directions in this rapidly evolving field.

Excellent energy storage performance of Nd-modified lead-free AgNbO3 ceramics via triple collaborative optimization

Lead-free Dielectric capacitors that possess high power density as well as swift charging/discharging speed are in tremendous requirement in pulse/high power fields, but the lower recovery energy density and efficiency restrict their applications. Herein, via triple collaborative optimization, we designed Nd-modified AgNbO3 antiferroelectric ceramics with excellent energy storage performance. First, Nd3+ ions are smaller than Ag+ ions, which effectively inhibits cation displacements and the tilting of oxygen octahedra, leading to an optimized phase composition, the suppressed ferroelectricity and enhanced antiferroelectricity. Second, the valence of Nd3+ ions are higher than that of Ag+ ions, which help to lower the content of oxygen vacancies. Third, the random substitution of Nd3+, extrinsic ions, cause the chemical disorder, thus dwindling the grain size. Both of the latter could boost the breakdown field. Eventually, the synchronously boosted energy density of 7.16 J/cm3 and efficiency of 72 %, together with excellent frequency stability, temperature tolerance, ultrafast charging/discharging time of 45 ns and superhigh power density of 354.2 MW/cm3, are achieved in Ag0.91Nd0.03NbO3. All these merits manifest Nd- AgNbO3 as a promising candidate for lead-free high-power energy storage devices. Our work brings forward a good reference for developing the capabilities of antiferroelectric capacitors.

Ultrahigh Energy Storage in (Ag,Sm)(Nb,Ta)O3 Ceramics with a Stable Antiferroelectric Phase, Low Domain-Switching Barriers, and a High Breakdown Strength.

AgNbO3 (AN) antiferroelectrics (AFEs) are regarded as a promising candidate for high-property dielectric capacitors on account of their high maximum polarization, double polarization-electric field (P-E) loop characteristics, and environmental friendliness. However, high remnant polarization (Pr) and large polarization hysteresis loss from room-temperature ferrielectric behavior of AN and low breakdown strength (Eb) cause small recoverable energy density (Wrec) and efficiency (η). To solve these issues, herein, we have designed Sm3+ and Ta5+ co-doped AgNbO3. The addition of Sm3+ and Ta5+ reduces the tolerance factor, polarizability of B-site cations, and domain-switching barriers, enhancing AFE phase stability and decreasing hysteresis loss. Meanwhile, adding Sm3+ and Ta5+ leads to decreased grain sizes, increased band gap, and reduced leakage current, all contributing to increased Eb. As a benefit from the above synergistic effects, a high Wrec of 7.24 J/cm3, η of 72.55%, power density of 173.73 MW/cm3, and quick discharge rate of 18.4 ns, surpassing those of many lead-free ceramics, are obtained in the (Ag0.91Sm0.03)(Nb0.85Ta0.15)O3 ceramic. Finite element simulations for the breakdown path and transmission electron microscopy measurements of domains verify the rationality of the design strategy.

Photo‐Curable Stretchable High‐k Polymer/TiO2 Nanosheet Hybrid Dielectrics for Field‐Effect Transistors

Elastomeric polymer materials are of interest due to their stretchability, low‐temperature processing, and scalability. In addition, the incorporation of 2D materials can further enhance the dielectric properties and capacitance of elastic polymer materials, thereby reducing the driving voltage and energy consumption. In this study, titanium dioxide (TiO2) nanosheets are cross‐linked with nitrile butadiene rubber using thiol‐ene click chemistry, which leads to the preparation of nanocomposite dielectric films with stretchability and high dielectric constant. Furthermore, by controlling the doping amount of the nanosheets, it is observed that the capacitance of the nanocomposite films increases from 25.61 to 684.67 nF cm−2, and the dielectric constant increases from 14.96 to 161.98. Finally, the stretchable nanocomposite films exhibit good insulating properties even at 50% strain. In this study, insight is provided into the potential of in situ cross‐linking between elastic polymer materials and 2D materials to produce high‐k dielectric materials with both stretchability and high insulating properties.

Enhanced energy storage and mechanical properties in niobate-based glass-ceramics

The advancement of energy storage glass-ceramics, serving as quintessential elements within pulse power capacitors, is deemed essential for the progression of sophisticated electronic systems, attributable to their ultrafast discharge rate and elevated dielectric breakdown strength (DBS). In this study, the incorporation of 1.2 mol% Nd2O3 into SiO2-Na2O-K2O-BaO-Nb2O5-Nd2O3 (SNKBNN) glass-ceramics has significantly enhanced the material performance. Specifically, a high recoverable energy storage density (Wrec) of 2.06 J/cm3 can be achieved, alongside an ultrahigh efficiency (η) of 92.3 % under an electric field of 630 kV/cm. Additionally, this glass-ceramics also exhibit a high discharge energy density (Wd) of 0.97 J/cm3, an ultrafast discharge rate of 7 ns, and an exceptionally high hardness (Hv) of 10.51 GPa. Additionally, these glass-ceramics exhibit exceptional stability across a range of temperatures (25 to 150 ℃), frequencies (10 to 1000 Hz), and cycling durability (up to 104 cycles). The research has corroborated the structural interdependence between energy storage and mechanical properties, establishing a foundational understanding of their synergistic relationship. The synthesized glass-ceramics demonstrate significant potential for use in high-power dielectric capacitors.

Sandwich-structured polymer dielectrics exhibiting significantly improved capacitive performance at high temperatures by roll-to-roll physical vapor deposition

Electrostatic capacitors with ultrahigh power density are the key components in modern electrical and electronic systems. Polymers are preferred dielectrics for high-voltage electrostatic capacitors, however, unable to meet the ever-growing high-temperature requirements in emerging applications, such as electric vehicles, and photovoltaic power generation. In this work, sandwich-structured Polyphenylene sulfide (PPS) films with Al2O3 as the coating layer have been prepared by using roll-to-roll magnetron sputtering. The incorporation of Al2O3 coating layers enhances the potential barrier height at the electrode/dielectric interface, thereby impeding charge injection from electrodes and suppressing high-temperature electrical conduction. Consequently, the sandwich-structured PPS films demonstrate significantly improved breakdown strengths and enhanced capacitive performance at elevated temperatures compared to neat PPS films. The roll-to-roll magnetron sputtering process employed in fabricating these sandwich-structured dielectric films is highly compatible with large-scale capacitor film production. Thus, sandwich-structured PPS films hold promise in addressing the challenge of scalable fabrication of high-performance, high-quality polymer films required for high-temperature capacitive energy storage.