Enhancement Of Energy Storage Performance Research Articles

Enhancement of energy storage performance of supercapacitors based on MoS2-g-C3N4 Nanocomposite electrodes

Enhancement of energy storage performance of supercapacitors based on MoS2-g-C3N4 Nanocomposite electrodes

The enhancement of energy storage performance of BaTiO3–Bi(Mg0·5Ti0.5)O3 Pb-free ceramics via an optimized viscous polymer process route

In this study, the viscous polymer processing (VPP) technique is implemented to optimize the characteristics of bulk (1-x)BaTiO3-xBi(Mg0·5Ti0.5)O3 (BT-xBMT) lead-free relaxor ferroelectric ceramics, with a focus on enhancing the recoverable energy storage density (Wrec), improving breakdown strength resistance (Eb), and increasing storage efficiency (η). The influence of polyvinyl alcohol (PVA) inclusion in the VPP process on the resulting dielectric ceramics is thoroughly investigated, covering rheological, dielectric, and ferroelectric properties. The results reveal that a gradual increase in PVA quantity during the VPP process effectively improves the density of ceramic blanks. However, an excess of PVA leads to void formation in the ceramic blanks post-debinding, hindering the achievement of a dense structure in the final ceramics and causing performance degradation. The resulting BT-0.405BMT-40 wt% PVA ceramic showed excellent storage performance, with Wrec, η, and Eb of 6.55 J/cm3 81.45 %, and 480 kV/cm, respectively. In comparison to bulk BT-0.405BMT ceramics, there is a notable 2.47-fold increase in Wrec and a 1.92-fold increase in Eb, accompanied by a substantial improvement in η. Moreover, the BT-BMT-40 wt% PVA ceramic exhibits favorable temperature stability (30–150 °C), frequency stability (1–50 Hz), and commendable charge/discharge performance.

Langmuir–Blodgett assisted alignment of 2D nanosheets in polymer nanocomposites for high-temperature dielectric energy storage applications

The Langmuir–Blodgett deposition technique enables a precise in-plane alignment and a densely packed arrangement of CNO nanosheets within the PEI matrix, resulting in a significant enhancement of energy storage performance at 150 °C.

Simultaneous enhancement of energy storage performance and thermal stability of NaNbO3-based ceramics via multi-scale modulation

More and more attention is being paid to the environmental friendliness of the dielectric capacitors, which have a rapid charging and discharging speed and steady operation. However, the low recoverable energy storage density (Wrec) limits the practical application of dielectric capacitors in solid-state energy storage devices. In this paper, (1–x) (0.92NaNbO3-0.08Bi(Mg0.5Ti0.5)O3)-xSrTiO3(x = 0.05, 0.10, 0.15, 0.20) energy storage ceramics were fabricated based on various strategies such as nanodomain engineering, component and grain size optimization. Thus excellent energy storage performance (Wrec ∼ 6.0 J/cm3, η ∼ 81.0%) was obtained in NN-BMT-0.15ST. SrTiO3 could enhance the internal disorder, improve the relaxation properties and increase the breakdown field strength of ceramics. Signifi-cantly domain relaxor behavior, as evidenced by Vogel-Fulcher (V-F) model, provides strong evidence for restraining early polarization saturation. In addition, Pulse charge/discharge tests have illustrated that the sample has excellent and stable charge/discharge performance (CD ∼ 1,068.9 A/cm2, PD ∼ 96.1 MW/cm3, t0.9 ≈ 0.99 μs) It is concluded that there is a huge prospect of NN-BMT-0.15ST ceramics as a kind of pulsed-power-storing electronics.

Energy Storage Performance and Dielectric Properties of Surface Fluorinated BOPP Films

Various composite films with high energy storage performance and/or dielectric strength have been fabricated. However, due to some reasons, few of them have been used in practice, and BOPP film is still regarded as the state-of-the-art capacitor dielectric film. Previous work has indicated that direct fluorination can improve the dielectric strength of BOPP films. Herein, as a continuation of previous work, the energy storage performance and basic dielectric properties of the surface fluorinated BOPP film are investigated. The charge-discharge experimental results show that the surface fluorinated BOPP sample has the maximum energy storage or release density of 5.27 or 4.43 J/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , which is 59.8% or 44.6% higher than that of the virgin BOPP sample. The dielectric measurement results indicate that the surface fluorinated BOPP sample has slightly higher dielectric constant and dielectric loss than the virgin BOPP sample. The analyses of physicochemical characteristics reveal that the 0.75 μm thick fluorinated surface layer has a high degree of fluorination. The results of the calculation based on the three-layer dielectric model and the dielectric measurements further show that the fluorinated surface layer has high dielectric constant and loss factor, similar to non-perfluoropolymers. The enhancement of energy storage performance and dielectric strength is mainly attributed to the blocking of the fluorinated layer to electron injection from the cathode, due to a 60% reduction of the interfacial electric field and a decrease in free volume of the surface layer by the fluorination.

Excellent energy storage performance of Mn-doped SrTiO3-BiFeO3 thin films by microstructure modulation

Dielectric thin film capacitors are expected to be a promising candidate for high-performance energy storage devices due to their high power density, fast charge/discharge speed, and excellent stability. Nevertheless, it remains a challenging endeavor to develop dielectrics with excellent energy storage density comparable to that of commercial batteries. In this work, lead-free 0.8SrTiO3-0.2BiFeO3 (0.8STO-0.2BFO) thin films with coexisting amorphous and nanocrystalline structure were prepared by a sol-gel method. The heat-treatment temperature was adjusted to form polar-nano regions, thereby modulate the breakdown strength and dielectric polarization, and increase the energy storage density. The electric potential, electric field, and current density of the films with different amorphous/crystalline volume fractions were evaluated by the finite element simulation to further verify that the proper crystallization can result in the improved polarization performance and increased breakdown strength of the films, which are beneficial to the enhancement of energy storage performance. Through structural tailoring, the 0.8STO-0.2BFO film annealed at 550 °C demonstrates the optimal energy storage properties with a giant discharge energy storage density of 65 J/cm3 and high efficiency of 75% at room temperature. Simultaneously, a broad temperature stability (20–160 °C), superb operating frequency stability (20 Hz-2 kHz), and excellent fatigue endurance (6.3 ×105) are observed without appreciable degradation of the energy storage performance. The excellent energy storage performance indicates a widespread potential of 0.8STO-0.2BFO films in pulse power applications, such as consumer electronics, microelectronics, and medical devices.

Suppression of the ferroelectric phase for (K0.5Na0.5)NbO3 ceramic by A/B-sites disorder for enhancement the energy storage properties and dielectric breakdown strength

In the present study, we propose a new strategy called suppression ferroelectricity of (K0.5Na0.5)NbO3 (KNN) lead-free ceramics for significant enhancement of energy storage properties (ESPs) and dielectric breakdown strength (DBSs). Both of pure KNN and (Na0.6Ag0.1Bi0.1)(Nb0.8Ti0.25)O3 (abbreviate NN-ABT) were synthesized using solid reaction technique. The crystal structure, dielectric and ferroelectric properties of both prepared ceramics were investigated. NN-based ceramics shown ferroelectric to relaxor phase crossover with pseudo-cubic crystal structure at ambient temperature. Present relaxor phase is attributed to substitution of monovalent (K1+) by trivalent (Bi3+) which can cause A-site cation vacancies and charge misfit of KNN lattice. The inhabitation of grain size to sub-micrometer observed by scanning electron microscope and this could be attributed to the lower ionic radius of (Ag1+ = 1.15 Å) and (Bi1+ = 1.38 Å) compared to (K1+ = 1.64 Å) which can suppressed the tolerance factor (τ) from 1.01 for KNN (ideal ferroelectric phase) to τ = 0.85 for NN-ABT . Suppression of the (τ) value can enhanced the degree of the relaxor phase, while inhibition of grain size can improved the DBSs or Eb. Superior enhancement of energy storage properties were achieved in NN-based ceramic due to hybridization between Bi3+ 6 P and O2- 2 P orbitals instead of K1+ 1 S and O2- 2 P orbitals which resulting in increasing the maximum polarization. The results shown that (NN-ABT) is acquired the preeminent of recoverable energy storage density Wrec ∼ 11 J/cm3, energy storage efficiency (ƞ = 89%) at E = 550 kV/cm. Furthermore, the sample shown an excellent thermal and frequency stabilities variation in a wide range of temperature (25–175 °C) and frequency (2–50 Hz). The significant enhancement in energy storage performance of NN-ABT ceramic is attributed to disturb the ferroelectric phase of KNN and forming PNRs of relaxor phase at ambient temperature. Therefore, the present study provides a good guideline for optimizing the ESPs and DBSs of NN-based ceramics to be more applicable for pulsed power and energy storage applications.

Enhancement of energy storage performance in lead‐free relaxor ferroelectric ceramics via band structure engineering

AbstractDielectric capacitors with excellent energy storage performance (ESP) are in great demand in the power electronics industry due to their high power density. For the dielectric materials, the dielectric breakdown strength (BDS) is the key factor to improve ESP, which is the focus and bottleneck of current research, especially in the relaxor ferroelectric (RFE) materials with already low residual polarization (Pr). Here, we stimulate the ESP of the BaTiO3 (BT)‐based RFE ceramics by band structure engineering. The Ta element is selected to enhance the band gap of doped ceramics, occupying Ti‐site in supercell of BT and optimizing the bonds length of Ti‐O bond to increase the energy band of Ti 3d states. In this way, the band gap of the doped ceramics is efficiently enhanced from 1.8 eV to 2.22 eV resulting in the large BDS. Prospectively, combined with the advantage of fine grain size, the highest recoverable energy storage density (Wrec) of 2.85 J/cm3 is obtained at 350 kV/cm and the ultra‐high energy efficiency (η) of 95.26% is found at 200 kV/cm. Our work reveals the relationship between elements doping in B‐site and band structure, being expected to benefit for designing energy storage materials.

Effect of acceptor-donor co-doping on the energy storage performance of antiferroelectric PBLZST

Synthetically enhancing the recoverable energy density (Wrec) and efficiency (η) is important to energy storage dielectric capacitors. ABO3 perovskite structure material (Pb0.96-αBa0.04Laα)(Zr0.65Sn0.3Ti0.05)O3 (PBLZST) is a typical antiferroelectric energy storage dielectric and has been widely studied due to the high polarization. But its low breakdown strength (Eb) limits its further application. Many researchers focused on single-doping in PBLZST and achieved high Eb or η, but synthetical enhancement is still a difficulty. In this work, we conducted A-site acceptor-donor co-doping and B-site acceptor-donor co-doping in PBLZST, respectively. Li and La were introduced into PBLZST at A-site and Nb-Mn were co-doped in PBLZST at B-site. XRD and EDS patterns suggest the pure phase of these doped samples. It is found that Li-La co-doping and Nb-Mn co-doping can both increase the breakdown strength from 156.2 kV/cm (pure PBLZST) to 304.5 kV/cm and 273.3 kV/cm, respectively. While, the Wrec also respectively increases to 5.56 J/cm3 (Li-La) and 3.71 J/cm3 (Nb-Mn) from 2.97 J/cm3, suggesting a comprehensive enhancement in energy storage performance. The mechanism of the enhancement was discussed. This work can provide a strategy to regulate and control the energy storage performance.

Enhancement of Energy Storage Performance of PMMA/PVDF Composites by Changing the Crystalline Phase through Heat Treatment.

In today's contemporary civilization, there is a growing need for clean energy focused on preserving the environment; thus, dielectric capacitors are crucial equipment in energy conversion. On the other hand, the energy storage performance of commercial BOPP (Biaxially Oriented Polypropylene) dielectric capacitors is relatively poor; hence, enhancing their performance has drawn the attention of an increasing number of researchers. This study used heat treatment to boost the performance of the composite made from PMAA and PVDF, combined in various ratios with good compatibility. The impacts of varying percentages of PMMA-doped PMMA/PVDF mixes and heat treatment at varying temperatures were systematically explored for their influence on the attributes of the blends. After some time, the blended composite's breakdown strength improves from 389 kV/mm to 729.42 kV/mm at a processing temperature of 120 °C. Consequently, the energy storage density is 21.12 J/cm3, and the discharge efficiency is 64.8%. The performance has been significantly enhanced compared to PVDF in its purest state. This work offers a helpful technique for designing polymers that perform well as energy storage materials.

The enhancement of energy storage performance in high-entropy ceramic

Dielectric capacitors are used in pulsed power devices due to their high-power density. The energy storage density and efficiency need to be further improved to widen their applications. This work investigates the energy storage of high entropy ceramic (Pb0.25Ba0.25Ca0.25Sr0.25)TiO3 synthesized by the solid-state method. The Bi(Mg2/3Nb1/3)O3 (BMN) is introduced to enhance its energy storage performance. The introduction of BMN from x = 0 to 0.15 reduces the grain size from 5.9 μm to 245 nm, increases the band gap from 2.98 to 3.05 eV, and improves the differences between saturation and remnant polarization from 11.85 to 14.60 μC/cm2. The phase diagram of this system was constructed by dielectric properties analysis to understand the effect of Bi(Mg2/3Nb1/3)O3 in the energy storage performance. The optimal energy density of 5.58 J/cm3 and efficiency of 89.4% was achieved in 0.9PBCST-0.1BMN which can be promising candidates for application in dielectric energy storage.

On the Enhancement of Energy Storage Performance in Modified Relaxor Ferroelectric Ceramics for Pulsed Power Applications

Relaxor-type ferroelectrics show important potential in energy storage fields due to their significantly enhanced energy performance and good temperature stability compared to normal ferroelectrics. Here, a novel, high-performance ternary composition, (0.4−x)BiFeO3-xBi(Mg1/2Ti1/2)O3–0.6BaTiO3 (x = 0.2, 0.25, 0.3, 0.35, 0.4), was designed by compositional modulation, which displays typical relaxor characteristics. The optimum energy storage properties can be attained at x = 0.35, accompanied by energy efficiency of 84.87%, a promising energy storage density of 2.3 J/cm3 and good temperature stability of less than 10% over 20–160 °C. Moreover, the samples provide stable cycling fatigue after 105 cycles and a fast discharge time of t0.9 &lt; 0.1 μs, indicative of promising applications in energy units.

Tuning Ba/Sr ratios of BaxSr1-xTiO3 of polymer nanocomposites toward significant enhancement of energy storage performance by optimized phase composition

The rapid development of portable electronic equipment, hybrid electric vehicles and pulse power systems have put forward higher requirements for new dielectric materials, making flexible polymer dielectrics attractive. Barium strontium titanate nanoparticles with different compositions were successfully prepared by using oxalate. A series of PVDF/BaxSr1-xTiO3 nanoparticles nanocomposites were prepared using the semi-crystalline ferroelectric polymer polyvinylidene fluoride PVDF as the polymer matrix. The microstructure and electrical properties of the nanocomposites were characterized to explore the effects of the composition and intrinsic properties of the filling phase on the nanocomposites. Among all the groups of nanocomposites, the 1 vol% PVDF/Ba0.6Sr0.4TiO3@DA NPs has the highest discharge energy density at the breakdown field strength, which is 7.8 J/cm3. The excellent discharge energy efficiency of 1 vol% PVDF/Ba0.6Sr0.4TiO3@DA NPs is maintained at 65 % at 300 kV/mm. This paper can provide experimental guidance and theoretical basis for the development of high energy storage density dielectric materials and their application in dielectric energy storage capacitors.

Enhancement of energy storage performance in NaNbO3 and Sm3+ modified BNT-based ceramics

Dielectric capacitors of excellent performance will possess high recoverable energystoragedensity (Wrec) and energy efficiency (η), and operate stably in extreme environments, such as at high temperature, high electric field intensity, and high frequency. In this study, lead-free relaxor ferroelectric(1-x)(0.85Bi0.5Na0.5TiO3–0.15Ba0.94Sm0.06TiO3) –xNaNbO3[(1-x)(BNT-BSmT)–xNN)] ceramics were prepared by a traditional solid phase sintering method to achieve excellent energy storage performance. The addition of Sm3+and NN locally disrupted the long-range ordered structure of the domain and inhibited grain growth due to limited grain boundary diffusion.The recoverable energy storage density and energy efficiency of the sample with an NN doping content ofx = 0.12 reached 2.42 J/cm3 and 81.18% at an applied electric field of 170 kV/cm, respectively. The efficiency remained stable (∼80%) at variable frequency (0.1–100 Hz) and temperature (20–140 °C). Furthermore, the0.88(0.85BNT–0.15BSmT)–0.12NN ceramic underwent rapid charge and discharge processes and achieved high power density (41.5 MV/cm3) at fast discharge rates (1.39 J/cm3). The new lead-free relaxor ferroelectric ceramics involved inthis study have great potential applications in the pulse capacitor field and a large temperature range.

Enhancement in energy storage performance of La-modified bismuth-ferrite-based relaxor ferroelectric ceramics by defect compensation and process optimization

In this investigation, La2O3 was doped into 0.85(0.65BF-0.35BT)-0.15Sr0.7Bi0.2TiO3 (BF-BT-SBT) to form a solid solution with relaxation ferroelectric properties. The dielectric breakdown strength (BDS) of 1% mole of La doping was 220 kV/cm, the maximum recoverable energy storage (Wrec) was 2.35 J/cm3, and the energy storage efficiency (η) was 71%. The relationship between ceramic properties and microstructure was investigated in detail. Doping with La has the following main features: (1) The dissolution of La3+ ions in the A position of the original perovskite structure reduced the concentration of oxygen vacancies in the lattice and played a role of compensating the defects. (2) The dielectric loss of ceramics was reduced, the impedance was greatly increased, and the specimen exhibited a high-temperature stability: a maximum Wrec of 4.04 ± 1.7% J/cm3 in 30–130 °C. (3) The core–shell–like with single phase structure in La-doped ceramics had been successfully observed, which may become a strategy for preparing high-performance ceramics. Higher BDS and denser structures were obtained in 0.01 La ceramics by further optimizing the preparation of the above compositions by the viscous polymer process (VPP). The BDS of 0.01La ceramics prepared by VPP reached 480 kV/cm, the effective energy storage density reached 6.15 J/cm3, and the η was about 81%. This made La-doped 15SBT (chemical composition of BF-BT-SBT + La2O3) ceramics become a potential candidate material for energy storage devices.

Enhancement of energy storage performance in lead-free barium titanate-based relaxor ferroelectrics through a synergistic two-step strategy design

Dielectric capacitors are widely used because of their advanced performance, including superior power density and high charge–discharge speed. Nevertheless, limitations in energy-storage density (Wrec), efficiency (η) and thermal stability hinder their practical application. Herein, these concerns are addressed using a synergistic two-step strategy of designing the composition of Bi(Zn2/3Nb1/3)O3 and optimizing the preparation for viscous polymer processing (VPP), thus achieving domain engineering, enhanced relaxor behavior, and improved breakdown strength (Eb) in (Ba0.8Sr0.2)TiO3-based ceramics. The broadening of the permittivity peak and highly dynamic polar nanoregions (PNRs) are correlated to expected relaxation characteristics, as indicated by the brightness of atomic position and calculated spontaneous polarization vectors determined through transmission electron microscopy. The relatively small grain size and increased band gap, verified through scanning electron microscopy and ultraviolet − visible spectrophotometry, contribute to the Eb. A prominent Wrec of 5.16 J/cm3 under 540 kV/cm and excellent temperature stability (Wrec = 3.6 J/cm3, η = 92.8%, 20–120 °C) are achieved in 0.91(Ba0.8Sr0.2)TiO3 − 0.09Bi(Zn2/3Nb1/3)O3 ceramics formed by VPP (BZN9VPP). The material possesses an exceptional current density of 647.56 A/cm2, a power density of 113.32 MW/cm3, and a rapid discharge speed of < 60 ns. The comprehensive outstanding performance supports the great potential of this sample for application in pulsed power capacitors.

Enhancement of Energy Storage Performance in Lead-Free Barium Titanate Ceramics Via Band Structure Engineering

Enhancement of Energy Storage Performance in Lead-Free Barium Titanate Ceramics Via Band Structure Engineering

Phosphoric acid involved laser induced microporous graphene via proton conducting polybenzimidazole for high-performance micro-supercapacitors

Functional electrodes with unique ion storage and rapid ion migration properties through microstructure and chemical-doping modulation are always crucial for rapid charging devices such as micro-supercapacitors (MSCs). In this work, proton exchange membrane named phosphoric acid (PA) doped polybenzimidazole membrane (PA-PBI) is studied as a unique precursor for assembling laser induced graphene (LIG) based electrodes (PA-PBI-LIG) in MSCs, toward the enhancement of energy storage performance via simultaneous heteroatoms doping, microporous structure improving and proton-conducting substrate introducing. By tuning PA concentration, the microporous structures perform adjustable specific surface area from 20.2 to 384.46 m2 g−1, thereby enhancing changeable capacitance from 2.44 mF cm−2 to 149 mF cm−2, with highest specific energy density of 20.7 μWh cm−2. To understand the mechanism, PA and the initiated free radicals are proposed to motivate microporous formation and heteroatoms doping during laser fabrication via unique laser absorption properties of PA. Additionally, PA-PBI substrates work synergistically on ions migration with microporous graphene, potentially promoting energy storage efficiency especially in the acid-based electrolyte. Overall, the raised PA-PBI-LIG electrodes simultaneously promote microporous, heteroatomic and multilayered graphene with proton conducting substrate, which show great potentials in micro energy storage devices.

Ultrahigh energy storage capacity with superfast discharge rate achieved in Mg-modified Ca0.5Sr0.5TiO3-based lead-free linear ceramics for dielectric capacitor applications

For the urgent demand of environmental protection and energy conservation, it is of great significance to develop environmentally-friendly dielectric ceramics with outstanding characteristic of energy storage and quick charge discharge capacity. For this study, we applied a strategy to achieve the enhancement of energy storage performance in (Ca0.5Sr0.5)1-xMgxTiO3 (abbreviate as CSMTx, x = 0.005, 0.010, 0.020, 0.040) linear ceramics based on the introduction of Mg2+ ion. Scanning electron microscopy and complex impedance measurement reveal that Mg2+ ion doping can refine grain size and increase grain boundary density, which results in grain boundary barrier strengthening owing to high-resistance grain boundaries. As a result, the marvellous energy storage properties, including an ultrahigh recoverable energy density of 2.88 J/cm3 combined with a giant energy efficiency of 90% are concurrently obtained in (Ca0.5Sr0.5)0.99Mg0.01TiO3 ceramic at an enhanced breakdown field (460 kV/cm). Meanwhile, this composition ceramic also exhibits the superior stability of frequency (1–1000 Hz) and temperature (20–100 °C) with minimal variation. In addition, the actual performance of ceramic capacitors in operation can be evaluated via the pulsed charge-discharge process. Delightedly, the superfast discharge speed (t0.9 = 20.4 ns), large current density (CD) of 421.23 A/cm2 and ultrahigh power density (PD) of 25.27 MW/cm3, as well as prominent thermal stability (20–100 °C) are synchronously produced in the CSMT2 ceramic. These merits qualify the unleaded linear ceramic as a competitive candidate for high-power capacitor applications, which offers a practicable approach for exploration on high-performance dielectric materials.

Ferroelectric properties of BaTiO3-BiScO3 weakly coupled relaxor energy-storage ceramics from first-principles calculations

Weakly coupled relaxor ferroelectrics BaTiO3-BiMeO3 (Me symbolizes trivalent or averagely trivalent cations) have received growing interest for energy-storage applications due to their extremely low remnant polarizations and slim hysteresis, which therefore provides high energy density and energy efficiency. Although large experimental progress has been made, there is still a lack of theoretical understanding from the electronic and atomic point of view. In this paper, by targeting the prototypical BaTiO3-BiScO3 (BT-BS) weakly coupled energy-storage ceramics, we investigated the ferroelectric properties at the electronic and atomic scale using first-principles calculations coupled with a phenomenological theory model. Results show that the lattice volumes expand with the increase of BS content, and an indirect band structure was found for the BT-BS ceramics. Ferroelectric polarizations become reduced and hysteresis loops get slimmer with the addition of BS. Moreover, large ionic displacement disorder of Ti/Sc atoms and strong orbital hybridization of Bi/Ti atoms with O atoms were discovered, which should serve as an origin of the reduced ferroelectric polarization and contribute to the weakly coupled relaxor behavior of the BT-BS ceramics. The employed methods and conclusions in this work should also be applicable to other BaTiO3-BiMeO3 ceramic systems, shedding light on the further enhancement of energy-storage performance from the electronic and atomic scale.