High-temperature Energy Storage Research Articles

Long-term replenishment strategy of SiC-doped Mn-Fe particles for high-temperature thermochemical energy storage

Thermal chemical energy storage (TCES) is a promising technology for large-scale energy storage, but long-term use of TCES materials can lead to attrition and reaction performance deterioration, compromising heat storage capacity and system continuity. To tackle this challenge, it is imperative to develop effective replenishment strategies and investigate the evolution of TCES materials. In this study, SiC-doped Mn-Fe particles exhibited superior performance, with only 1.87% mass loss ratio after 4.32×105 rotations attrition testing and a reaction conversion of 91.7% even after 800 reaction cycles. However, assessing material suitability for TCES systems necessitates analyzing both attrition resistance and reaction performance. A replenishment strategy was proposed, based on the attrition conversion factor and analysis of dissipated energy of particles in concentrated solar power (CSP) plants. Compared to undoped Mn-Fe particles, the annual replenishment ratio was reduced by one order of magnitude for SiC-doped particles, to only 1.26% (0.5 wt% SiC) and 0.994% (1 wt% SiC). The replenishment strategy and strengthened particles result in curtailed particle fines and particle flow interruption, and enhanced economics. Continuous replenishment strategy can undoubtedly cater to the requisite heat storage capacity demands for protracted system operation and extend system stability, promoting the advancement of TCES technology.

A Bi-Gradient Dielectric Polymer/High-Κ Nanoparticle/Molecular Semiconductor Ternary Composite for High-Temperature Capacitive Energy Storage.

Attaining compact energy storage under extreme temperature conditions is of paramount importance in the development of advanced dielectric materials. The polymer composite approach has proved effective towards this goal, and addressing the correlation between filler distribution and electrical properties is foremost in designing composite dielectrics, especially in multifiller systems. Here, the design of a bi-gradient polymer composite dielectric using an integrated framework based on the phase field model is reported. This framework can predict the charge-inhibiting behavior of composite dielectrics, which is a key factor impacting the high-temperature capacitive performance but unfortunately is ignored in conventional phase field models. It is found that due to the traps provided by the functional organic fillers, more carriers are trapped near the electrodes and weaken the electric field, thus significantly suppressing the breakdown initialization process. An interpenetrating gradient structure is designed rationally and synthesized experimentally, which exhibits concurrent high energy density (5.51 J cm-3 ) and high charge-discharge efficiency (90%) up to 200 °C. This work provides a strategy to predict the high-temperature energy storage performance of polymer composites containing charge-inhibiting components and helps broaden the scope of data-driven materials design based on phase-field modeling.

Simultaneously realizing ultrahigh energy storage density and efficiency in BaTiO3-based dielectric ceramics by creating highly dynamic polar nanoregions and intrinsic conduction

Nowadays, it is urgent to explore advanced and eco-friendly energy storage capacitors based on lead-free relaxor ferroelectric (RFE) ceramics in order to meet the ever-increasing requirements in pulsed power systems. BaTiO3 (BT)-based RFE ceramics are considered as ones of the best high-temperature energy storage materials due to their good thermal stability. However, relatively low recoverable energy storage density (Wrec<5 J/cm3) has been a key bottleneck restricting the practical applications of them. Here, a novel strategy is proposed to create highly dynamic PNRs and the intrinsic conduction by introducing Bi(M1-0.015xTa0.015x)O3+0.015x (BMO-Ta, M=Mg2/3Ta1/3) to BT matrix. As a consequence, the designed (1-x)BT-x(BMO-Ta) ceramics exhibit dramatically enhanced energy storage properties including ultrahigh Wrec and efficiency (η), because of the coexistence of very slim polarization hysteresis (P-E) loops, large polarization difference (ΔP) and giant dielectric breakdown electric strength (Eb). Wrec and η of the x=0.25 ceramic reach up to 9.03 J/cm3 and 95.2% under 720 kV/cm, respectively. Furthermore, it shows excellent temperature/frequency/cycling stability over a wide range of 20−200 °C, 1−500 Hz and 1−3.3 × 105 cycles, respectively (the variations of Wrec and η are < 3% and < 4%, respectively). The findings in this paper not only indicate excellent comprehensive properties achieved in the novel (1-x)BT-x(BMO-Ta) system, but also provide an effective approach to explore advanced energy storage capacitors in other lead-free ceramic systems.

Carboxylated Poly (p-Phenylene Terephthalamide) Reinforced Polyetherimide for High-Temperature Dielectric Energy Storage.

Dielectric energy storage polymers play a vital role in advanced electronics and electrical systems, due to their high breakdown strength, excellent reliability, and easy fabrication. However, the low dielectric constant and poor thermal resistance of dielectric polymers limit their energy storage density and working temperatures, making them less versatile for broader applications. In this work, a novel carboxylated poly (p-phenylene terephthalamide) (c-PPTA) is synthesized and employed to simultaneously enhance the dielectric constant and thermal resistance of polyetherimide (PEI), leading to a discharged energy density of 6.4 J cm-3 at 150 °C. The introduction of c-PPTA molecules effectively reduces the ΠΠ stacking effect and increases the average chain spacing between polymer molecules, which is conducive to improving the dielectric constant. Additionally, c-PPTA molecules with stronger positive charges and high dipole moments can capture electrons, resulting in reduced conduction loss and enhanced breakdown strength at high temperatures. The coiled capacitor fabricated with the PEI/c-PPTA film exhibits superior capacitance performances and higher working temperatures compared to commercial metalized PP capacitors, demonstrating great potential for dielectric polymers in high-temperature electronic and electrical energy storage systems.

Quantum size effect to induce colossal high-temperature energy storage density and efficiency in polymer/inorganic cluster composites.

Polymer dielectrics need to operate at high temperatures to meet the demand of electrostatic energy storage in modern electronic and electrical systems. The polymer nanocomposite approach, an extensively proved strategy for the performance improvement, encounters the bottleneck of reduced energy density and poor discharge efficiency beyond 150°C. Here, we report a polymer/metal oxide cluster composite prepared based on the "site isolation" strategy. Capitalizing on the quantum size effect, the bandgap and surface defect states of the ultra-small inorganic clusters (2.2nm diameter) are modulated to markedly differ from the regular-sized nanoparticles. Experimental results in conjunction with computational simulation demonstrate that, the presence of ultra-small inorganic clusters can introduce more abundant, deeper traps in the composite dielectric with respect to the conventional polymer/nanoparticle blends. Unprecedented high-temperature capacitive performance including colossal energy density (6.8 Jcm-3 ), ultra-high discharge efficiency (95%) and superior stability at different electric field frequencies, are achieved in these polymer/cluster composites up to 200°C. Along with the advantages in material preparation (inexpensive precursors and one-pot synthesis), such polymer/inorganic cluster composite approach is promising for high-temperature dielectric energy storage in practical power apparatus and electronic devices. This article is protected by copyright. All rights reserved.

The scalable and high performance polyimide dielectrics containing alicyclic structures for high-temperature capacitive energy storage

Polyimide (PI) dielectrics have attracted much attention in the field of film capacitors because of outstanding high temperature resistance, well film-forming and mechanical properties. However, high conductive loss leads to low energy density and efficiency at elevated temperatures, which is caused by the conjugation effect of the benzene ring on the main chain of PI. In order to solve this problem, a semi-aromatic PI with alicyclic structure is designed and prepared. Compared with the all-aromatic PI (Kapton), the semi-aromatic PI exhibits much higher discharge energy density (Ud) and efficiency (η) at room temperature and high temperature. In particular, at the classical operating condition, i.e. 200 MV m−1 and 150 °C, the Ud (0.78 J cm−3) is nearly twice that of biaxially oriented polypropylene (BOPP) (0.4 J cm−3) and the η of 95% is achieved in the semi-aromatic PI. Based on the experimental data, the concept of charge transfer complex and simulation results, alicyclic structure in the main-chain of PI not only can avoid the formation of electron channels due to staggered stack of benzene rings, but also can increase the bandgap width, resulting in the increment of breakdown strength and the decrement of conductive loss. This work demonstrates that the semi-aromatic PI dielectrics containing alicyclic structure are ideal energy storage materials used in the extreme condition.

Towards low-temperature processing of lead-free BZT thin films for high-temperature energy storage performance

In this work, lead-free BaZr0.35Ti0.65O3 (BZT) thin films were grown on silicon by using pulsed laser deposition. The phase structures of the BZT thin films were controlled via the deposition temperature, and their effects on the breakdown strength and energy-storage performance were systematically investigated. Our results indicate that the BZT thin films deposited at a low temperature of 450 °C have a paraelectric phase and display the highest recoverable energy density of 121.2 J/cm3 and a medium energy efficiency of 88.2%. The ultrahigh energy storage achieved is mainly due to the remarkable improvement in the breakdown strength and the slimmer and slanted polarization hysteresis loop. Moreover, the BZT thin films demonstrate excellent thermal stability across a wide temperature measurement range (25–200 °C) and a superior fatigue endurance of up to 1010 switching cycles even under a high temperature measurement of 200 °C. This work provides a simple and effective way of improving the energy storage properties and stable performance of dielectric thin films for application in harsh environments.

Enhancing the high-temperature energy storage performance of PEI dielectric film through deposition of high-dielectric PZT coating layer

Dielectric film capacitors are a highly ubiquitous and indispensable electronic component, serving a crucial role in a wide array of electronic devices and power systems. Despite their extensive use, polymer film capacitors are often hampered by the conduction loss that ensues when they are subjected to high electric fields and temperatures. As a result, this leads to a significant reduction in energy density and charge-discharge efficiency. To solve this issue, magnetron sputtering technology was used to create a sandwich structure made of polyetherimide (PEI) thin films with lead zirconate titanate (PZT) inorganic layers coated on both sides. This remarkable innovation has successfully introduced the high dielectric PZT layer in the PEI film/metal electrode, substantially augmenting the barrier height at the dielectric/polymer interface. This has also resulted in a marked decrease in conduction loss, as conclusively validated by the experimental findings. At 150 °C and with charge-discharge efficiency above 90%, the maximum discharged energy density is 3.26 J/cm3, which is increased by 263% compared to the pristine PEI films (1.24 J/cm3 at 290 MV/m and 150 °C). This study designed a unique inorganic barrier layer of PZT to increase the energy storage capability of polymer dielectric films in high-temperature environments.

Designing tailored combinations of structural units in polymer dielectrics for high-temperature capacitive energy storage

Many mainstream dielectric energy storage technologies in the emergent applications, such as renewable energy, electrified transportations and advanced propulsion systems, are usually required to operate under harsh-temperature conditions. However, excellent capacitive performance and thermal stability tend to be mutually exclusive in the current polymer dielectric materials and applications. Here, we report a strategy to tailor structural units for the design of high-temperature polymer dielectrics. A library of polyimide-derived polymers from diverse combinations of structural units are predicted, and 12 representative polymers are synthesized for direct experimental investigation. This study provides important insights into decisive structural factors necessary to achieve robust and stable dielectrics with high energy storage capabilities at elevated temperature. We also find that the high-temperature insulation performance would experience diminishing marginal utility as the bandgap increases beyond a critical point, which is strongly correlated to the dihedral angle between neighboring planes of conjugation in these polymers. By experimentally testing the optimized and predicted structures, an increased energy storage at temperatures up to 250 °C is observed. We discuss the possibility for this strategy to be generally applied to other polymer dielectrics to achieve further performance enhancement.

具有分级界面的纳米纤维增强聚合物复合材料: 用于高温介电储能应用

Flexible polymer nanocomposites reinforced by high-dielectric-constant ceramic nanofillers have shown great potential for dielectric energy storage applications in advanced electronic and electrical systems. However, it remains a challenge to improve their energy density and energy efficiency at high temperatures above 150°C. Here, we report a nanofiber-reinforced polyetherimide nanocomposite employing BN-BaTiO3 heterogeneous nanofibers as fillers, where the BN nanoparticles were embedded inside BaTiO3 nanofibers to create BN/BaTiO3/PEI hierarchical interfaces. The high dielectric constant and the geometric large aspect ratio of the BN-BaTiO3 heterogeneous nanofibers lead to simultaneously increased dielectric constant and breakdown strength of the nanocomposite over a broad temperature range. In particular, the emerging hierarchical BN/BaTiO3/PEI interfaces enable promoted density and energy level of traps for the mobile charges, which further suppresses the conduction loss and improves the breakdown strength under high temperatures, as confirmed by a combination of thermally stimulated depolarization current measurement and phase-field simulation. Finally, the nanocomposite with hierarchical interfaces boosts an ultrahigh energy density of 5.23 J cm−3 with an energy efficiency of > 90% at 150°C, which is the highest energy density reported so far in nanofiber-reinforced polymer nanocomposites and also outperforms most nanocomposites counterparts dispersed with nanoparticles and nanosheets. Our work demonstrates hierarchical interface engineering as an effective strategy to promote the high-temperature energy storage performance of fiber-reinforced polymer nanocomposites, which is of significance for their applications in high-temperature harsh conditions.

All-organic nanocomposite dielectrics contained with polymer dots for high-temperature capacitive energy storage

All-organic nanocomposite dielectrics contained with polymer dots for high-temperature capacitive energy storage

연소시스템 화석연료 사용량 저감을 위한 잠열에너지저장 기술동향 연구: Part II 상변화물질의 열전달 특성과 열교환기 설계유형, 실증사례

Following the publication of Part 1, Part 2 focuses on the development trends of key element technologies associated with heat transfer characteristics. Previous research focused on methods to overcome low thermal conductivity, and various heat exchanger design methods have been proposed to improve this using solid media such as fins or additives such as carbon particles. In addition, the operation method for optimal performance, when the latent heat energy storage system is connected to the main combustion system, is discussed. Finally, demonstration research cases, which are being conducted in Germany and Korea, are introduced to discuss the current status and future direction of this technological development in combined heat and power, and steam generation. In Korea, R&D for a latent heat energy storage system, through waste heat recovery, is an ongoing national project and is scheduled to be demonstrated in 2025. Projects involved in high-temperature latent heat energy storage technology to reduce carbon emissions, by reducing the direct use of fossil fuels, are currently ongoing.

Gallium Nitride Based Electrode for High-Temperature Supercapacitors.

Gallium nitride (GaN) single crystal, as the representative of wide-band semiconductors, has great prospects for high-temperature energy storage, of its splendid power output, robust temperature stability, and superior carrier mobility. Nonetheless, it is an essential challenge for GaN-based devices to improve energy storage. Herein, an innovative strategy is proposed by constructing GaN/Nickel cobalt oxygen (NiCoO2 ）heterostructure for enhanced supercapacitors (SCs). Benefiting from the synergy effect between the porous GaN network as a highly conductive skeleton and the NiCoO2 with massive active sites. The GaN/NiCoO2 heterostructure-based SCs with ion liquids electrolyte are assembled and delivered an impressive energy density of 15.2µWhcm-2 and power density, as well as superior service life at 130°C. The theoretical calculation further explains that the reason for the energy storage enhancement of the GaN/NiCoO2 is due to the presence of the built-in electric fields. This work offers a novel perspective for meeting the practical application of GaN-based energy storage devices with exceptional performance capable of operation under high-temperature environments.

Polymer/Graphene Nanocomposites via 3D and 4D Printing—Design and Technical Potential

Graphene is an important nanocarbon nanofiller for polymeric matrices. The polymer–graphene nanocomposites, obtained through facile fabrication methods, possess significant electrical–thermal–mechanical and physical properties for technical purposes. To overcome challenges of polymer–graphene nanocomposite processing and high performance, advanced fabrication strategies have been applied to design the next-generation materials–devices. This revolutionary review basically offers a fundamental sketch of graphene, polymer–graphene nanocomposite and three-dimensional (3D) and four-dimensional (4D) printing techniques. The main focus of the article is to portray the impact of 3D and 4D printing techniques in the field of polymer–graphene nanocomposites. Polymeric matrices, such as polyamide, polycaprolactone, polyethylene, poly(lactic acid), etc. with graphene, have been processed using 3D or 4D printing technologies. The 3D and 4D printing employ various cutting-edge processes and offer engineering opportunities to meet the manufacturing demands of the nanomaterials. The 3D printing methods used for graphene nanocomposites include direct ink writing, selective laser sintering, stereolithography, fused deposition modeling and other approaches. Thermally stable poly(lactic acid)–graphene oxide nanocomposites have been processed using a direct ink printing technique. The 3D-printed poly(methyl methacrylate)–graphene have been printed using stereolithography and additive manufacturing techniques. The printed poly(methyl methacrylate)–graphene nanocomposites revealed enhanced morphological, mechanical and biological properties. The polyethylene–graphene nanocomposites processed by fused diffusion modeling have superior thermal conductivity, strength, modulus and radiation- shielding features. The poly(lactic acid)–graphene nanocomposites have been processed using a number of 3D printing approaches, including fused deposition modeling, stereolithography, etc., resulting in unique honeycomb morphology, high surface temperature, surface resistivity, glass transition temperature and linear thermal coefficient. The 4D printing has been applied on acrylonitrile-butadiene-styrene, poly(lactic acid) and thermosetting matrices with graphene nanofiller. Stereolithography-based 4D-printed polymer–graphene nanomaterials have revealed complex shape-changing nanostructures having high resolution. These materials have high temperature stability and high performance for technical applications. Consequently, the 3D- or 4D-printed polymer–graphene nanocomposites revealed technical applications in high temperature relevance, photovoltaics, sensing, energy storage and other technical fields. In short, this paper has reviewed the background of 3D and 4D printing, graphene-based nanocomposite fabrication using 3D–4D printing, development in printing technologies and applications of 3D–4D printing.

Enhanced energy density at elevated temperature in polyetherimide based all-organic dielectrics via UV irradiation

The rapid development of electrostatic capacitors puts forward more stringent requirements for the use of polymer dielectrics, that is, to maintain high energy storage density and efficiency under extreme environments of high temperature and high electric field. In this work, all-organic composites comprising polyetherimide (PEI) blended with high-electron-affinity polymer dots (PDs) have been fabricated and modified by UV irradiation. It is found that the UV irradiated all-organic composites exhibit high energy density (4.1 J cm−3), far outperforming pristine PEI. The energy level diagram and electric conduction results prove that PDs capture free electrons via electrostatic attraction and the wide bandgap forms a barrier to electron transport, which inhibits the electric conduction, leading to the substantial performance improvements. This work demonstrates an effective modification method for the improvement of high-temperature electronics and energy storage devices.

Sandwiched Polymer Nanocomposites Reinforced by Two-Dimensional Interface Nanocoating for Ultrahigh Energy Storage Performance at Elevated Temperatures.

Polymer-based dielectrics are essential components in electrical and power electronic systems for high power density storage and conversion. A mounting challenge for polymer dielectrics is how to maintain their electrical insulation at not only high electric fields but also elevated temperatures, in order to meet the growing needs for renewable energies and grand electrifications. Here, a sandwiched barium titanate/polyamideimide nanocomposite with reinforced interfaces via two-dimensional nanocoatings is presented. It is demonstrated that boron nitride and montmorillonite nanocoatings can block and dissipate injected charges, respectively, to present a synergetic effect on the suppression of conduction loss and the enhancement of breakdown strength. Ultrahigh energy densities of 2.6, 1.8, and 1.0 J cm-3 are obtained at 150 °C, 200 °C, and 250 °C, respectively, with a charge-discharge efficiency >90%, far outperforming the state-of-the-art high-temperature polymer dielectrics. Cyclic charge-discharge tests up to 10 000 times verify the excellent lifetime of the interface-reinforced sandwiched polymer nanocomposite. This work provides a new pathway to design high-performance polymer dielectrics for high-temperature energy storage via interfacial engineering.

High temperature energy storage and release properties of polyimide nanocomposites simulated by considering charge trapping effects

AbstractDielectric energy storage capacitors with excellent high temperature resistance are essential in fields such as aerospace and pulse power. However, common high‐temperature resistant polymers such as polyimide (PI) and polyether sulfone have low energy storage densities and energy efficiencies at high temperature, which are greatly limited in practical applications. The polymer nanocomposites prepared by doping modification can regulate the charge injection and transport process, and improve the high‐temperature energy storage performance. However, the quantitative relationship between charge injection and charge trapping and the energy storage performance of linear polymer nanocomposites still needs further study. An energy storage and release model considering the charge trapping effects is constructed by the authors. We simulate the high‐temperature energy storage properties of polyimide nanocomposite dielectrics (PI PNCs) with different charge injection barriers and trap parameters at 150°C. A triangular voltage is applied to the electrodes at both sides of the PI PNCs, the electric displacement‐electric field loop is simulated, and the discharged energy densities and energy efficiencies are calculated. The simulation results are consistent with the experimental results. Increasing the charge injection barrier, deep trap energy and deep trap density can effectively reduce the charge injection and the carrier mobility, thereby improving the discharged energy densities and energy efficiencies of dielectric capacitors. In the case of low charge injection barrier (1.3 eV), with the increase of deep trap energy (0.7–1.5 eV) and deep trap density (1 × 1021–1 × 1025 m−3), the discharged energy density changes from 0.20 to 1.44 Jcm−3, the energy efficiency changes from 9.0% to 99.9%, and the high‐temperature energy storage performance improves significantly. This research provides theoretical and model support for the improvement of the high‐temperature energy storage performance of nanocomposites.

Ladderphane copolymers for high-temperature capacitive energy storage.

For capacitive energy storage at elevated temperatures1-4, dielectric polymers are required to integrate low electrical conduction with high thermal conductivity. The coexistence of these seemingly contradictory properties remains a persistent challenge for existing polymers. We describe herea class of ladderphane copolymers exhibiting more than one order of magnitude lower electrical conductivity than the existing polymers at high electric fields and elevated temperatures. Consequently, the ladderphane copolymer possesses a discharged energy density of 5.34 J cm-3 with a charge-discharge efficiency of 90% at 200 °C, outperforming the existing dielectric polymers and composites. The ladderphane copolymers self-assemble into highly ordered arrays by π-π stacking interactions5,6, thus giving rise to an intrinsic through-plane thermal conductivity of 1.96 ± 0.06 W m-1 K-1. The high thermal conductivity of the copolymer film permits efficient Joule heat dissipation and, accordingly, excellent cyclic stability at elevated temperatures and high electric fields. The demonstration of the breakdown self-healing ability of the copolymer further suggests the promise of the ladderphane structures for high-energy-density polymer capacitors operating under extreme conditions.

High-temperature polymer dielectrics with superior capacitive energy storage performance

Polymer dielectrics for high-temperature capacitive energy storage are extremely desirable in modern electronics and electrical systems. However, pure polymer dielectrics operating above 200 °C have yet not been reported. Here, we demonstrate a polymer dielectric polynorbornene-imide (PNI) exhibits excellent energy storage performances at 250 °C owing to simultaneous large optical bandgap (4.3 eV) and high glass transition temperature (265 °C) endowed by the full-carbon backbone and rigid side chain containing benzene ring and the imide group. Significantly, PNI delivers a maximum discharged energy density (Ud) of 6.04 J/cm3 at 200 °C and a Ud of 2.57 J/cm3 at 250 °C. More importantly, PNI exhibits a Ud above 90% efficiency of 2.8 J/cm3 at 200 °C, and 0.74 J/cm3 at 250 °C, outperforming reported all pure polymer dielectrics and polymer composites dielectrics so far. The excellent recycling stability, fast discharge capability and unique self-healing capacity enables it a promising candidate for capacitor films in industry. This work provides a new design strategy for polymer dielectrics under harsh environments.

High Performance Low-Temperature Lithium Metal Batteries Enabled by Tailored Electrolyte Solvation Structure.

The electrochemical performances of lithium metal batteries are determined by the kinetics of interfacial de-solvation and ion transport, especially at low-temperature environments. Here, a novel electrolyte that easily de-solvated and conducive to interfacial film formation is designed for low-temperature lithium metal batteries. A fluorinated carboxylic ester, diethyl fluoromalonate (DEFM), and a fluorinated carbonate, fluoroethylene carbonate (FEC) are used as solvents, while high concentrated lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is served as the solute. Through tailoring the electrolyte formulation, the lithium ions in the high concentrated fluorinated carboxylic ester electrolyte are mainly combined with anions, which weakens the bonding strength of lithium ions and solvent molecules in the solvation structure, beneficial to the de-solvation process at low temperature. The fluorinated carboxylic ester (FCE) electrolyte enables the LiFePO4 (LFP) | Li half-cell achieves a high capacity of 91.9 mAh g-1 at -30 °C, with high F content in the interface. With optimized de-solvation kinetics, the LFP | Li full cell remains over 100 mAh g-1 at 0 °C after cycling 100 cycles. Building new solvents with outstanding low-temperature properties and weaker solvation to match with Li metal anode, this work brings new possibilities of realizing high energy density and low temperature energy storage batteries.