Capacitor Applications Research Articles

Mg-MOF-Derived hierarchical porous carbon fiber electrodes for efficient capacitive deionization

The development of metal organic framework (MOF) functionalized carbon nanofiber with high flexibility has attracted significant attention in the fields of electrochemistry and capacitive deionization. Especially, MOF materials with alkaline earth metal centers offer advantages such as cost-effectiveness, non-toxicity, and ease of preparation. In this study, we introduced a simple strategy for synthesizing hierarchical porous carbon nanofibers derived from Mg-MOF-containing electrospun fiber (HCNF/Mg) and explored their application in capacitive deionization (CDI). The resulting HCNF/Mg exhibits a flexible structure and boasted specific surface area (908.42 m2/g), thus providing an efficient electrosorption interface to facilitate the fast ionic diffusion. Under optimum conditions, the CDI desalination capacity achieves 22.10 mg/g, accompanied with an ultrafast adsorption rate of 2.2 mg/g/min. Furthermore, this material demonstrates remarkable stability, maintaining the capacity of 90 % over 40 cycles, positioning it as a promising candidate for practical CDI applications.

Superior energy storage performance achieved in tungsten bronze SBCN-based ceramics through tape-casting

Simultaneously integrating outstanding energy storage density and good energy storage efficiency in advanced ferroelectrics is crucial to implementing the application of dielectrics in high-power pulse devices. In this work, (Sr0.5Ba0.5)2Ca0.5Nb5-xSbxO15 ceramics were designed and prepared by adopting the B sites substitution engineering together with combining strategies of tape-casting method and two-step sintering process. Benefiting from the refined grain size and high density, the breakdown field of (Sr0.5Ba0.5)2Ca0.5Nb4.8Sb0.2O15 (SBCNS0.2) was promoted to 400 kV/cm. By the substitution of Sb5+ in the B sites, the weaker interaction force of Sb-O bond in BO6 octahedral polar unit induced the occurrence of polar nanoregions (PNRs) at room temperature to strengthen the dielectric relaxation behavior. Then it is noteworthy that SBCNS0.2 ceramics simultaneously obtained excellent recoverable energy density (Wrec, 3.9 J/cm3), energy storage efficiency (η, 90.5 %), power density (PD, 156.0 MW/cm3), and current density (CD, 1356.7 A/cm2). In addition, the SBCNS0.2 ceramics exhibited an ultrafast discharge time (t0.9, 67 ns). These results reveal prospective potential of unfilled tungsten bronze SBCNS0.2 ceramics in power capacitor applications and provide an effective strategy for improving excellent energy storage properties from the perspective of preparation methods.

Ultrahigh Energy Storage Performance of BiFeO3-BaTiO3 Flexible Film Capacitor with High-Temperature Stability via Defect Design.

Nanoengineering polar oxide films have attracted great attention in energy storage due to their high energy density. However, most of them are deposited on thick and rigid substrates, which is not conducive to the integration of capacitors and applications in flexible electronics. Here, an alternative strategy using van der Waals epitaxial oxide dielectrics on ultra-thin flexible mica substrates is developed and increased the disorder within the system through high laser flux. The introduction of defects can efficiently weaken or destroy the long-range ferroelectric ordering, ultimately leading to the emergence of a large numbers of weak-coupling regions. Such polarization configuration ensures fast polarization response and significantly improves energy storage characteristics. A flexible BiFeO3-BaTiO3 (BF-BT) capacitor exhibits a total energy density of 43.5 J cm-3 and an efficiency of 66.7% and maintains good energy storage performance over a wide temperature range (20-200 °C) and under large bending deformation (bending radii ≈ 2mm). This study provides a feasible approach to improve the energy storage characteristics of dielectric oxide films and paves the way for their practical application in high-energy density capacitors.

Doublet doped titanate ferroelectric system for capacitors and NTC thermistor applications

A simple negative temperature coefficient (NTC) thermistor Ba0.85Sr0.15Ti0.85Zr0.15O3 system is elaborated using a conventional solid-state reaction route. The structural analysis confirms that the elaborated pseudo-cubic system, which is indexed in the P4mm space group, exhibits one single phase. The dielectric properties and the electrical resistivity data are investigated over a large temperature range from 413 K to 673 K. In this temperature interval, the Steinhart–Hart equations are employed to confirm that Ba0.85Sr0.15Ti0.85Zr0.15O3 is a promising system for sensor application. Accordingly, the thermistor constant (β=10154 K), the sensitivity factor (-5.5 %/K≤α≤-2 %/K), the activation energy (Ea=0.875 eV), and the stability factor (SF=2.27) parameters are calculated to approve that Ba0.85Sr0.15Ti0.85Zr0.15O3 exhibits an NTC-thermistor behavior. The temperature dependence of the electrical resistivity confirms that Ba0.85Sr0.15Ti0.85Zr0.15O3 reveals a semiconductor behavior. The dielectric investigation shows that Ba0.85Sr0.15Ti0.85Zr0.15O3 exhibits a motivating dielectric properties (elevated dielectric constant value (105<ε’<106) and low dielectric losses (mostly < 0.007) with almost frequency independence between 20 Hz to 500 kHz). The colossal dielectric response of Ba0.85Sr0.15Ti0.85Zr0.15O3 is attributed to the internal barrier layer capacitor (IBLC) and the surface barrier layer capacitor (SBLC) effects. Such response suggests the suitability of Ba0.85Sr0.15Ti0.85Zr0.15O3 ceramic for high temperature capacitor applications.

Outstanding energy storage properties under moderate electric field in BiMg2/3Nb1/3O3-modified NaNbO3-based relaxor ceramics

NaNbO3 (NN)-based ceramics have received a great deal of attention for the potential application in dielectric energy storage capacitors. However, the energy storage properties (ESP) remain low, particularly under moderate electric field. Herein, a Bi-rich doping unit of BiMg2/3Nb1/3O3 (BMN) was introduced into a 0.85NaNbO3-0.15Bi0.1Sr0.85TiO3 (NN-SBT) matrix, aiming to improve polarization along ESP. As a result, a large recoverable energy density (Wrec) of ∼6.1 J/cm3 and an efficiency (η) of ∼81 % were achieved in NN-SBT-0.08BMN ceramics under a moderate electric field of 337 kV/cm. The improved ESP can be attributed to the introduction of BMN, which delays the polarization saturation of NN-SBT ceramics, while maintaining the maximum polarization (∼43.6 μC/cm2), and generating polar nanoregions (PNRs). Moreover, the optimal ceramics exhibited good thermal (25–130 °C) and frequency (1–300 Hz) stabilities, and fatigue endurance (>105 cycles). These results illustrate that the designed NN-SBT-0.08BMN ceramics are promising for application in dielectric energy storage capacitors with high ESP under a moderate electric field.

Outstanding energy density and charge-discharge performances in Sr2KNb5O15-based tungsten bronze ceramics for dielectric capacitor applications

Relaxor ferroelectric ceramics are extremely encouraging materials for energy storage capacitor applications in pulse equipment. As the second largest ferroelectric ceramic system, tungsten bronze structure relaxor ferroelectric ceramics have emerged as a significant contender and garnered significant attention in the pulse capacitor research field. In this work, an Sb-modified Sr2KNb5O15-based tungsten bronze relaxor ferroelectric ceramic system is designed to explore its energy storage potential. XRD refinement reveals the declines in the oxygen octahedra tilting and distortion after the introduction of Sb, which significantly augments the relaxation behavior. Additionally, refined grain size and reduced oxygen vacancy concentration are observed, greatly improving the breakdown strength. Consequently, a superior energy storage density (∼4.57 J/cm3) accompanied by wonderful energy storage efficiency (∼89.3 %) is received at 540 kV/cm, with wide frequency stability and great thermal stability. Moreover, amazing discharging performances are also achieved with rapid discharge speed (τ0.9 < 70 ns), towering discharge current density (815.2 A/cm2) and surprising power density (130.4 MW/cm3). All these performances indicate that the designed Sr2KNb5O15-based tungsten bronze relaxor ferroelectric ceramic can be one encouraging option in the dielectric energy storage field.

Synthesis and Characterization of 3D MnNi2O4@MnNi2S4/NF-MOF-67-rGO nanoflower@nanosheet for ultra-high capacity electrode material

Abstract This study reports a novel 3D MnNi2O4@MnNi2S4/NF-MOF-67-rGO core-shell nanoflower@nanosheet synthesized at very high temperature and pressure shows an outstanding electrode substance for ultra-high super capacitor. The structure of MnNi2O4@MnNi2S4 was determined by using infrad red spectrum, scanning electron microscopic images and cyclic voltammetric techniques. The core (MnNi2O4) and shell (MnNi2S4) are both dynamic resources and they are involved in the Faraday redox processes to make possible the MnNi2O4@MnNi2S4 conducting device to acquire more electrochemical properties. The power capacitance of the MnNi2O4@MnNi2S4 electrode material reaches 805.09 C g−1 while the density of the current is 1.0 A g−1. Furthermore, the preservation rate of specific capacity of the MnNi2O4@MnNi2S4 electrode reaches 91.50% after the five thousand charge - discharge cycles while the density of current is 20.0 A g−1. The energy density for the MnNi2O4@MnNi2S4//AC material attains 74.64 Wh kg−1 at a energy density of 774.05 Wh kg−1. In addition, the MnNi2O4@MnNi2S4 //AC shows exceptional self-discharge properties. Therefore, the MnNi2O4@MnNi2S4 conducting device presents wide-ranging utilities and applications for capacitors of the battery-type. In this work, a novel 3D MnNi2O4@MnNi2S4 /NF-MOF-67-rGO core-shell nano arrangement was effectively grown-up on the Nickel foam via the reaction mixture growth technique, which misplaced the conductive additive and addition of binder and the complex method of electrode fabrication. It is quite remarkable that the maximum energy storage capacity of the 3D MnNi2O4@MnNi2S4/NF-MOF-67-rGO reaches 3579.60 F g−1 at the current density of 1.0 A g−1 and 1008.50 F g−1 at the current density of 20.0 A g−1. At a given density of current of 15.0 A g−1, the retention rate of maximum energy storage capacity reaches 94.10 % after 5 cycles, showing excellent cycling performances.

Ionic liquid based NCPBE membranes for electrochemical capacitor applications: Structural, thermal and electrical transport properties

The current study focuses on the preparation and characterisation of imidazolium ionic liquid based plasticized nano-composite polymer blend electrolytes (NCPBEs). Semi-crystalline nature of the synthesized samples was observed using XRD analysis. ATR-FTIR results demonstrate the interaction among the carbonyl (CO) and hydroxyl (O–H) groups of polymers with ionic liquid (IL) and salt, NaI. Furthermore, thermo-gravimetric analysis (TGA) indicates multi-step decomposition process. Ion transport mechanism has been analysed using temperature dependent conductivity analysis, ac conductivity analysis and dielectric properties study. The sample containing 25 wt% IL i.e. NCPBE-25 has the ionic conductivity ∼9.30 × 10−4 Scm−1 with the optimum vale of charge carrier density, mobility, and ion diffusivity at 30oC. Ions are principal charge carriers in the present electrolytes. The sample NCPBE-25 has the electro-chemical stability window −3.6 to 1.5 V at room temperature. The fabricated electro-chemical capacitor has the specific capacitance, energy density and power density 363.27 Fg-1, 50.45 Whkg−1 and 18.16 kW/kg, respectively at the scan rate 5 mV/s.

Enhanced energy density in cellulose doped polyimide-based all organic composites for high temperature capacitor applications

Abstract The growing demand for electronic devices has induced a significant requirement for high energy density capacitors. In this investigation, we introduced small groups of cyanoethyl cellulose (CEC) into a polyimide (PI) substrate to create all organic CEC/PI composite films for high energy density capacitor applications. Due to the large dipole moment in C–CN dipoles in CEC groups, the dielectric constant of the CEC/PI-5 (5% CEC) composite increased by 26.3% to 4.31. Compared to the pristine PI film at room temperature, the breakdown field of the CEC/PI-0.5 increased by 4.7% from 502.29 to 526.1 MV m−1 and the energy storage density increased by 95% to 11.70 J cm−3. Furthermore, the CEC/PI-0.5 film exhibited an energy density of 6.39 J cm−3 with the breakdown field of 400 MV m−1 at 150 °C, which is 93.05% higher in energy densities than that of the pristine PI film. Furthermore, simulation results indicate that CEC groups can introduce deep traps in the CEC/PI composite, which can inhibit charge movement in the composite and increase the breakdown field of it. In this study, it was found that by adding small amount of CEC polar group in PI film, the high temperature energy density of CEC/PI composite materials was significantly improved. This study not only makes a significant contribution to the development of high-temperature energy-density capacitors, but also pave a way by using small molecule polar polymers to improve the energy density of dielectric materials at high temperature.

Water/N,N-Dimethylacetamide-Based Hybrid Electrolyte and Its Application to Enhanced Voltage Electrochemical Capacitors

The growing interest in hybrid (aqueous–organic) electrolytes for electrochemical energy storage is due to their wide stability window, improved safety, and ease of assembly that does not require a moisture-free atmosphere. When it comes to applications in electrochemical capacitors, hybrid electrolytes are expected to fill the gap between high-voltage organic systems and their high discharge rate aqueous counterparts. This article discusses the potential applicability of aqueous–organic electrolytes utilizing water/N,N-dimethylacetamide (DMAc) solvent mixture, and sodium perchlorate as a source of charge carriers. The hydrogen bond formation between H2O and DMAc (mole fraction xDMAc = 0.16) is shown to regulate the original water and cation solvation structure, thus reducing the electrochemical activity of the primary aqueous solution both in the hydrogen (HER) and oxygen (OER) evolution reactions region. As a result, an electrochemical stability window of 3.0 V can be achieved on titanium electrodes while providing reasonable ionic conductivity of 39 mS cm−1 along with the electrolyte’s flame retardant and anti-freezing properties. Based on the diagnostic electrochemical studies, the operation conditions for carbon/carbon capacitors have been carefully optimized to adjust the potential ranges of the individual electrodes to the electrochemical stability region. The system with the appropriate electrode mass ratio (m+/m− = 1.51) was characterized by a wide operating voltage of 2.0 V, gravimetric energy of 13.2 Wh kg−1, and practically a 100% capacitance retention after 10,000 charge–discharge cycles. This translates to a significant rise in the maximum energy of 76% when compared to the aqueous counterpart. Additionally, reasonable charge–discharge rates and anti-freeze properties of the developed electrolyte enable application in a broad temperature range down to −20 °C, which is demonstrated as well.

Modulating zero charge potential of Zn-doped N, P-containing carbon electrodes for efficient copper ion electrosorption

Nitrogen/phosphorus (N/P) doped carbon materials exhibit enhanced electro adsorption capability in capacitive deionization (CDI) applications. However, the incorporation of N/P atoms may introduce electron-withdrawing groups to the electrode surface, impacting the potential of zero charge (EPZC) and thereby influencing its electro adsorption efficiency. This research explores the modulation of electrode surface charge by varying the N/P doping composition. Specifically, it presents a Zn and N/P co-doped carbon material employed as the CDI cathode, showcasing selective adsorption of Cu2+ ions. Under a voltage of 1.2 V, the adsorption capacity achieves 250 mg/g in a 500 mg/L Cu2+ ion solution. Furthermore, it demonstrates outstanding cycling stability, maintaining an adsorption capacity of 233 mg/g even after 21 cycles. This investigation introduces an innovative approach for EPZC adjustment and offers a fresh theoretical framework for fabricating high-performance CDI electrodes.

Enhanced comprehensive energy storage properties in Bi0.5Na0.5TiO3-based relaxor ferroelectric ceramics under a moderate electric field

Bismuth sodium titanate (Bi0.5Na0.5TiO3)-based relaxor ferroelectric ceramics have received ever-increasing interest for their potential application in dielectric capacitors owing to their sterling energy storage capability. Herein, the perovskite end-member Ba(Fe0.5Nb0.5)O3 (BFN) was incorporated into 0.7Bi0.5Na0.5TiO3-0.3SrTiO3 (0.7BNT-0.3ST) ceramics to improve the relaxor characteristics and refine the grain, leading to slim polarization–electric field (P–E) hysteresis loops and enhanced electric breakdown strength. Particularly, the 0.85(0.7BNT-0.3ST)-0.15BFN ceramics achieved a high recoverable energy density of 5.7 J/cm3 and a high energy storage efficiency of 86.4% under a moderate electric field of 390 kV/cm. Additionally, remarkable stability in frequency, cycling, and temperature and excellent charge/discharge behavior were achieved at the same time. The above findings reveal that BFN-modified BNT-ST ceramics display greatly improved comprehensive energy storage properties, making them promising candidates in the field of electrostatic energy storage.

Study of dielectric and interfacial properties of functional biopolymer-based electrolyte with enhanced conductivity for energy storage application

This study investigates sodium (Na+) ion-conductive biopolymer blend electrolytes with glycerol as a plasticizer for energy storage. Through FTIR, impedance spectroscopy, transference number measurement (TNM), and linear sweep voltammetry (LSV), we identify an optimal film for electric double layer capacitor (EDLC) application. Glycerol induces notable changes in polymer-salt interaction, evidenced by FTIR band shifts reflecting increased free ions. Impedance measurements show reduced bulk resistance with optimal plasticizer content, emphasizing the system's suitability for energy storage. The system exhibits high real permittivity relative to imaginary at lower frequencies, attributing to glycerol's dielectric constant and small bulk resistance. Loss tangent (tanδ) and Argand plots reveal the dominant ion conduction mechanism. Electrochemical assessments support the suitability of the film for EDLC applications, featuring a favorable transference number (tion = 0.94) and high decomposition voltage (2.6V). Cyclic voltammetry (CV) curves demonstrate effective EDLC device design with significant capacitance adaptability across varying scan rates (5.946 F/g to 24.074 F/g).

Advanced energy storage properties and multi-scale regulation mechanism in (1-x)(Bi0.5Na0.5)0.7Sr0.3TiO3-xCa(Nb0.5Al0.5)O3 relaxor ferroelectric ceramics

Since recently, lead-free dielectric ceramics have garnered significant interest for their high-power density and rapid charge-discharge capabilities. Nonetheless, their practical application is still limited by relatively low energy storage density and efficiency. To address this issue, a new class of relaxor ferroelectric ceramics ((1-x)(Bi0.5Na0.5)0.7Sr0.3TiO3-xCa(Nb0.5Al0.5)O3, with x from 0.00 to 0.16) was formulated and synthesized in the present work using a solid-state reaction method. Special attention was paid to the effect of multiscale structure regulation on the energy storage properties of the ceramics. All ceramics exhibited the relaxor characteristics, which increased with the added content of Ca(Nb0.5Al0.5)O3 (CNA). Significant achievements have been made in multi-scale regulation of energy storage characteristics of these ceramics. In particular, the ultrahigh energy storage density and efficiency (10.15 J/cm3 and 86.2 %, respectively) were realized in the ceramic with x = 0.14. This optimized composition also displayed good temperature stability at 20–140 °C and excellent frequency stability in the range of 1–200 Hz. Furthermore, the outstanding charge and discharge characteristics (current density CD, power density PD, and discharge time t0.9 of 1257 A/cm2, 377 MW/cm3, and 45.8 ns, respectively) were obtained. The experimental study, finite element analysis, and first-principles calculations confirmed that the multiscale features, such as nano-scale domains, large band gap, and small grain size, promoted by the addition of CNA, are all beneficial for the improvement of energy storage performance, opening up new prospects in the application of advanced dielectric capacitors.

Green Synthesis of Chlorophyta Seaweed Mediated Mn3O4 Nanoparticles: Electrochemical Applications and Evaluation of Capacitive and Diffusive Contributions

This study focuses on the sustainable synthesis of Mn3O4 nanoparticles using Chlorophyta seaweed extracts for electrochemical capacitor applications. X-ray diffraction (XRD), ultraviolet-visible (UV–Visible) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared (FTIR) spectroscopy were used to evaluate the produced nanoparticles to determine their crystallinity, structure, shape, and elemental composition. The XRD results showed diffraction peaks that correspond to the Hausmannite Mn3O4 phase, with a 24.4 nm-sized average crystallite. The electrochemical properties were examined through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). When compared to a bare Ni electrode, the electrochemical analysis showed a voltammetric response that was 17-fold higher. For the kinetics of the electrochemical reaction, the charge transfer coefficient (αa) and apparent electron transfer rate constant (k s) were determined to be 4.0 s−1 and 0.33, respectively. The diffusion coefficient, as evaluated using the Randles-Sevcik equation, was 1.78 × 10−6 cm2/s. The analysis conducted at various scan rates revealed a diffusive contribution of 90.6% at 5 mV/s and 67.7% at 100 mV/s. In contrast, at a scan rate of 100 mV/s, the capacitive contribution increased from 9.4 to 32.3%. The change in the time for the interaction between ions and electrode material is responsible for the reduction in the diffusive component and the increase in the capacitive component.

Optical and Dielectric Features of PVA/CMC/PVP/ZnMn2O4/CuCo2O4/x wt% MWCNTs Blended Polymers for Optoelectronic Applications

This study is devoted to optimizing the optical and dielectric parameters of polyvinyl alcohol (PVA)/ carboxymethyl cellulose (CMC)/ polyvinylpyrrolidone (PVP) blended polymer by adding ZnMn2O4/CuCo2O4 nanocomposite and controlling the amounts of multi-walled carbon nanotubes (MWCNTs) to engage them in flexible optoelectronics and storage energy capacitors. Herein, 0.9ZnMn2O4/0.1CuCo2O4 was synthesized by co-precipitation and hydrothermal methods and loaded with different ratios of MWCNTs into PVA/CMC/PVP blend to produce films by solution casting procedure. The crystallite size of 0.9ZnMn2O4/0.1CuCo2O4 was determined using transmission electron microscopy. The structures of the filler and doped blends were explored via the X-ray diffraction technique. The optical features of undoped and doped blends were explored by diffused reflectance and fluorescence spectrophotometers. The addition of ZnMn2O4/CuCo2O4 to PVA/CMC/PVP caused a decline of direct and indirect optical band gaps from 5.33 and 5.03 eV to 5.19 and 4.66 eV, respectively. By adding different amounts of MWCNTs, the direct/indirect optical band gap reduced irregularly, and they attained their minimum values (5.07, 4.46) eV as it doped with 0.6 Wt% MWCNTs. The highest values of refractive index, extinction coefficient, optical conductivity and nonlinear optical parameters were achieved in the blend containing ZnMn2O4/CuCo2O4/0.6 Wt% MWCNTs. It is also found that the dielectric constant and ac conductivity rose with the insertion of ZnMn2O4/CuCo2O4/0.6 Wt% MWCNTs. The highest energy density value was found in the polymer blend of PVA/CMC/PVP/ZnMn2O4/CuCo2O4/0.8 Wt% MWCNTs blended polymer. Electrical modulus and Nyquist plots for different blends were also examined. The results recommend the doped blends as a good candidate for optoelectronics and energy storage capacitor applications.

Insights into enhanced antiferroelectricity in doped-niobate perovskites for high energy-storage density applications

Lead-free antiferroelectric (AFE) ceramics have attracted increasing attention in recent years for application in high-power capacitors due to their environmental friendliness and high energy density. Among these ceramics, NaNbO3 is noteworthy as one of the few lead-free perovskites displaying an AFE structure. However, despite the nature of AFE symmetry in NaNbO3 with Nb antipolar state, in most cases, it behaves like a ferroelectric (FE) material with an external electric field and exhibits a single polarization-electric field (P-E) hysteresis loop. In order to enhance the antiferroelectricity, a composition modification strategy based on the tolerance factor (t) has been used to stabilize the AFE phase effectively. Yet, in the context of NaNbO3 ceramics, the impact of doping on the evolution of antiferroelectricity has remained unexplored. Through first-principles calculations, we unveil how the chemical modification of NaNbO3 enhances antiferroelectricity by investigating local distortions that favor the AFE state over the FE state in solid solutions. This adjustment in the relative stability between the FE state and AFE state results in a significant modification in the switching barrier in NaNbO3-based antiferroelectrics, ultimately leading to well-defined double polarization loops. This work offers a rationalized atomic-scale perspective on the AFE-FE phase transition in NaNbO3-based ceramics, aiming to contribute to the development of novel lead-free antiferroelectric oxides for energy storage applications.

Competing Charge Transfer and Screening Effects in Two-Dimensional Ferroelectric Capacitors.

Two-dimensional (2D) ferroelectrics promise ultrathin flexible nanoelectronics, typically utilizing a metal-ferroelectric-metal sandwich structure. Electrodes can either contribute free carriers to screen the depolarization field, enhancing nanoscale ferroelectricity, or induce charge doping, disrupting the long-range crystalline order. We explore electrodes' dual roles in 2D ferroelectric capacitors, supported by first-principles calculations covering a range of electrode work functions. Our results reveal volcano-type relationships between ferroelectric-electrode binding affinity and work function, which are further unified by a quadratic scaling between the binding energy and the transferred interfacial charge. At the monolayer limit, charge transfer dictates the ferroelectric stability and switching properties. This general characteristic is confirmed in various 2D ferroelectrics including α-In2Se3, CuInP2S6, and SnTe. As the ferroelectric layer's thickness increases, the capacitor stability evolves from a charge-transfer-dominated state to a screening-dominated state. The delicate interplay between these two effects has important implications for 2D ferroelectric capacitor applications.

High-temperature dielectric nanocomposite film of 2D Bi4Ti3O12/ABS with excellent energy storage performance

The utilization of high-temperature dielectrics in capacitive energy storage is of great significance in contemporary electronic systems. Nevertheless, the thermal stability of most emerging polymers exhibits a significant decline in their energy storage capacity as temperatures rise. In this study, a unique type of 2D Bi4Ti3O12 nanofillers was synthesized in order to improve the breakdown strength. A nanocomposite consisting of Bi4Ti3O12/poly(acrylonitrile-butadiene-styrene) (ABS) was synthesized with the aim of attaining enhanced dielectric characteristics and energy storage density under elevated temperatures. The Bi4Ti3O12/ABS nanocomposites exhibited notable temperature stability in relation to their dielectric and energy storage capabilities across a temperature range spanning from room temperature to 120 °C. Ultrahigh discharged energy density (Ue) of 12.44 J/cm3 for 3 wt%- Bi4Ti3O12/ABS nanocomposites and high efficiency of 87 % under 550 MV/m were achieved at room temperature. An excellent Ue of 9.12 J/cm3 and high efficiency of 86.2 % for 3 wt%- Bi4Ti3O12/ABS nanocomposites were also observed in 3 wt%- Bi4Ti3O12/ABS nanocomposites under 450 MV/m at 120 °C, which was 117 % and 114 % of ABS films. These capacitive performances could match or be higher than previously reported values for high-temperature capacitor applications.

Structural, dielectric, electrical, and energy storage properties of Mn‐doped Ba0.55Sr0.45TiO3 ceramics

AbstractA conventional solid‐state reaction route was utilized for the fabrication of Ba0.55Sr0.45Ti1−xMnxO3 (x = .004, .006, .008, .01, and .015) ceramics. X‐ray diffraction (XRD) diffractograms revealed pseudo‐cubic structural symmetry with a single phase. The scanning electron microscope (SEM) images revealed fine grain morphology for x = .006, while an obvious increase in grain size was detected at x &gt; .006. A high‐energy storage density (Ws) of 2.47 J cm−3 and a recoverable energy density (Wrec) of 1.36 J cm−3 at an applied electric field of 220 kV cm−1 were achieved for x = .006. An impedance spectroscopic study showed the electrical response relationship with microstructure. The observed two semicircles in Nyquist plots are an indication of the contribution of grains (bulk) and grain boundaries as a resistive medium for conduction of charge carriers, which led to enhanced the capability in capacitor applications.