Efficient Energy Storage Research Articles

Enhancing Building Energy Efficiency: Leaf Transpiration Inspired Construction of Lignin-Based Wood Plastic Composites for Building Energy Conservation

Incorporating phase change materials (PCMs) into buildings represents a strategic method for reducing reliance on air conditioning systems and decreasing energy usage consequently. Inspired by leaf veins providing channels for transpiration, lignin porous carbon (LPC) was synthesized by chemical activation, showing a vein pore structure. The capillary network system of the LPC provided more channel to adsorb PCM through surface tension and capillary force, achieving an impressive loading capacity of LPC for polyethylene glycol (PEG) (75%), which demonstrated exceptional heat storage capability (133.21 J/g). The lignin-derived wood-plastic composite (L-WPC) was further prepared. With the gradual increase of LPC/PEG, the latent heat of L-WPC increased gradually. The ΔHm, ΔHc and energy storage efficiency of L-WPC-50 (incorporated 50 wt% LPC/PEG-75) reached 39.99 J/g, 42.65 J/g and 90.26%, respectively. The vein pore structure of LPC also provided a thermal conductivity link for L-WPC. L-WPC-50 demonstrated an increased thermal conductivity (0.66 W/(m·K)) and a reduced thermal diffusion coefficient (0.24 mm2/s), optimizing the effectiveness of the phase transition. Additionally, L-WPC-50 displayed satisfactory mechanical properties and dimensional stability, with tensile strength, bending modulus and water absorption thickness swelling rate measuring 14.40 MPa, 1043.72 MPa, and 1.61% respectively. It introduced a feasible approach for utilizing biomass in enhancing building energy efficiency, marking a significant stride towards reducing building energy consumption and advocating sustainable energy practices.

Numerical study on solar photovoltaic/thermal system with tesla valve

In recent years, photovoltaic/thermal (PV/T) systems have played a crucial role in reducing energy consumption and environmental degradation, nonetheless, the low energy conversion efficiency presents a considerable obstacle for PV/T systems. Therefore, improving heat conversion efficiency is essential to enhance energy efficiency. In this paper, the PV/T system with the Tesla valve is proposed to solve this problem. Firstly, the cooling effect is simulated and analyzed in the system with four different flow channel structures: semicircle, rectangle, triangle and Tesla valve. The results indicate that the system with the Tesla valve exhibits superior cooling performance. Subsequently, several factors including angle, valve number, valve type, and pipe diameter ratio for the Tesla valve are further studied through numerical and simulation analysis. The results reveal that Tesla valves demonstrate optimal cooling performance when possessing the following structural parameters: complete symmetry, more valves, a 30-degree angle and a pipe diameter ratio of 1. Finally, four different types of fluid are selected to explore the Tesla valve. The conclusion shows that nanofluids with high density, low specific heat, and high thermal conductivity also improve the cooling performance. Thus, the PV/T system with the Tesla valve exhibits good heat dissipation and energy storage efficiency, electrical efficiency can reach 16.32% and thermal efficiency reach 59.65%.

Driving innovation in energy and telecommunications: next-generation energy storage and 5G technology for enhanced connectivity and energy solutions

Driving innovation in energy and telecommunications involves leveraging next-generation energy storage and 5G technology to enhance connectivity and energy solutions. This review explores the intersection of these two domains, highlighting the importance of advancements in energy storage and 5G technology for a sustainable and connected future. Energy storage is crucial for balancing the supply and demand of electricity in modern power systems. Traditional energy storage methods, such as batteries and pumped hydro, have limitations in terms of scalability, efficiency, and cost-effectiveness. Next-generation energy storage technologies, including advanced batteries, hydrogen storage, and thermal storage, offer promising solutions to overcome these limitations. These technologies enable efficient energy storage at scale, facilitating the integration of renewable energy sources like solar and wind into the grid. By storing excess energy generated during periods of low demand, next-generation energy storage systems ensure a reliable and stable power supply, reducing the reliance on fossil fuels and lowering greenhouse gas emissions. In parallel, the evolution of telecommunications technology, particularly the advent of 5G networks, is revolutionizing connectivity and communication. 5G technology offers significantly higher data transfer speeds, lower latency, and increased network capacity compared to its predecessors. These capabilities are essential for supporting emerging technologies such as the Internet of Things (IoT), autonomous vehicles, and smart grids. With 5G-enabled IoT devices, utilities can monitor energy consumption in real-time, optimize grid operations, and detect and respond to faults more efficiently. Moreover, 5G connectivity enhances the efficiency and reliability of energy storage systems by enabling seamless communication between distributed energy resources and grid operators. The convergence of next-generation energy storage and 5G technology presents numerous opportunities for driving innovation in both energy and telecommunications sectors. One of the key areas of innovation is the development of smart energy storage systems equipped with 5G connectivity. These systems can autonomously adjust their operation based on grid conditions, weather forecasts, and energy demand patterns, optimizing energy storage and distribution in real-time. Furthermore, advanced energy management algorithms leveraging artificial intelligence (AI) and machine learning (ML) algorithms can optimize energy usage and storage, further improving the efficiency and reliability of the grid. Another area of innovation lies in the integration of renewable energy resources with 5G-enabled microgrids. Microgrids are localized energy systems that can operate independently or in conjunction with the main grid. By combining renewable energy sources with energy storage and 5G-enabled communication, microgrids can provide reliable, clean, and resilient power to remote or urban areas. These microgrids can also facilitate peer-to-peer energy trading, allowing consumers to buy and sell excess energy within their communities, fostering energy independence and sustainability. Furthermore, advancements in battery technology, such as solid-state batteries and flow batteries, are enhancing the performance and reliability of energy storage systems. Solid-state batteries offer higher energy density, faster charging rates, and improved safety compared to conventional lithium-ion batteries. Flow batteries, on the other hand, provide scalability and long-duration storage capabilities, making them suitable for grid-scale applications. Integrating these advanced battery technologies with 5G-enabled monitoring and control systems enhances the overall resilience and flexibility of the energy infrastructure. In addition to technological advancements, driving innovation in energy and telecommunications requires collaboration among various stakeholders, including policymakers, regulators, industry players, and research institutions. Policies and regulations should incentivize the deployment of next-generation energy storage and 5G infrastructure, promote interoperability standards, and ensure data privacy and security. Public-private partnerships can facilitate the investment and deployment of innovative solutions, while research and development initiatives can spur further technological advancements. Driving innovation in energy and telecommunications through next-generation energy storage and 5G technology is essential for building a sustainable, connected, and resilient future. By leveraging advanced energy storage systems, smart grids, and 5G-enabled communication networks, we can optimize energy usage, reduce carbon emissions, and enhance the reliability and efficiency of our energy infrastructure. Collaboration and investment across various sectors are key to unlocking the full potential of these transformative technologies and achieving a brighter, more sustainable future for generations to come. Keywords: Innovation, Energy, Telecommunications, Next-Generation, 5G technology, Enhanced connectivity.

Improving phase change heat transfer in an enclosure partially filled by uniform and anisotropic metal foam layers

Anisotropic metal foams exhibit exceptional potential for improving the efficiency of latent heat thermal energy storage (LHTES) units by enhancing heat transfer and thermal energy storage rates. This study explores the largely uncharted area of thermal behavior of anisotropic metal foams in varied configurations and enclosure designs. The research focuses on an LHTES unit with a specific channel configuration, constructed using copper and containing three layers of copper metal foam, one of which is anisotropic and infused with paraffin wax. The finite element method was utilized to manage the complexities emerging from phase change, and the anisotropic angle varied from 0 to 90° in three different placements of the AMFL: top, middle, or bottom of the enclosure. The ideal design was achieved with an AMFL in the middle with a 0°angle, resulting in a 3.7 % reduction in melting time and approximately a 2.3 % reduction in solidification time. However, AMFL designs at the middle placement with a 75° anisotropic angle were less effective, hampering the melting and solidification processes, thus potentially extending charging and discharging times. The study concludes that the placement and angle of the AMFL layer are vital for the heat transfer capabilities of phase change materials. AMFL at the middle with a 0° angle optimally leverages temperature gradients, enhancing heat transfer compared to other investigated cases. An AMFL in the middle with a 0° angle exhibits approximately 7.1 % and 6.3 % improvements for melting fractions of 0.9 and 0.95, respectively, underscoring its potential for efficient thermal energy storage.

Sandwich-structured SrTiO3/PEI composite films with high-temperature energy storage performance

Dielectric capacitors are widely used in aerospace and power systems due to their non-polluting, high power density and fast charge/discharge rates. Polyetherimide (PEI) exhibits excellent temperature tolerance, high withstand voltage and low dielectric loss. However, its relatively low dielectric constant restricts its energy storage density. In this paper, a sandwich-structured composite film with the outer layer of pure PEI and the middle layer of strontium titanate (SrTiO3)/PEI is prepared by the solution casting method. At room temperature, the composite film with 5 vol% two-dimensional (2D) SrTiO3 plates achieves an outstanding energy storage density of 19.46 J cm−3 and an ultra-high energy storage efficiency of 97.05% under an electric field of 630 MV m−1. Furthermore, this composite film exhibits a maximum energy storage density of 10.34 J cm−3 and an energy storage efficiency of 88.13% at 150 °C. Combined with finite element simulation results, it confirms that the synergistic effect of 2D SrTiO3 plates and sandwich-structured can effectively hinder the development of electric trees. This work presents a sophisticated approach to design and preparation of dielectric composites suitable for the applications of high-temperature energy storage.

MXene-modified lemon peel-based composite phase change material with excellent photo-thermal conversion efficiency, thermal storage capacity and thermal conductivity for thermal management of electronic components

The preparation of multifunctional composite phase change materials using green technology to achieve an efficient energy storage and conversion remains an issue of concern. In this paper, a lemon peel-based porous carbon (LPC) composite phase change material (CPCM) was prepared by using polyethylene glycol (PEG) 6000 as a phase change medium and MXene nanosheet-modified carbonized lemon peel as a support carrier. MXene nanosheets were bonded to a lemon peel-based porous carbon skeleton to construct an excellent continuous three-dimensional thermally conductive grid system. What makes it noteworthy is that the presence of MXene nanosheets substantially improves the thermal conductivity (0.66 W/mK) and photo-thermal conversion efficiency (θ = 96.4 %) of MXene-modified lemon peel-based porous carbon/polyethylene glycol composite phase change materials (PEG/LPC@M). It is noteworthy that PEG/LPC@M has remarkable thermal stability and still has high enthalpy after 100 cycles, which further proves the recyclability of PEG/LPC@M and PEG/LPC@M embodies great potential in the field of thermal management of electronic components. In conclusion, a novel multifunctional CPCM was prepared by a simple and green process method in this study, which provides a new idea for waste recycling and reuse, and also has a wide range of applications in thermal management of electronic devices.

Enhancing the quality factor of aerosol jet printed RF spiral inductors through gold electroplating

Aerosol jet printing (AJP) outperforms inkjet printing by significantly reducing printed line width, effectively addressing issues such as bulging and surface irregularities. This technology allows for line widths as narrow as 10–100 μm with high aspect ratios, making it well-suited for radio frequency (RF) applications. Consequently, AJP emerges as a valuable tool for direct printing in RF applications. Among conductive inks, silver nanoparticle (Ag-NP) ink is preferred for its straightforward direct printing process and lower sintering temperature requirements. However, the conductivity of printed Ag NP traces falls markedly below that of bulk silver due to significant porosity, limiting its use in RF applications where a high-quality factor is essential. The quality factor of an inductor, indicative of its efficiency in energy storage and release, inversely correlates with its resistance. Our research combines AJP with selective electroplating to reduce the resistance of printed traces, thereby enhancing the inductor’s quality factor for RF applications. We fabricated spiral inductors on alumina substrates using silver NP ink and subsequently applied selective gold electroplating to these traces. This approach led to a significant increase in the inductors’ quality factor, improving it by a factor of 3–5 in the RF frequency range of 100–700 MHz.

An end-cloud collaboration approach for online state-of-health estimation of lithium-ion batteries based on multi-feature and transformer

State-of-Health (SOH) estimation of lithium-ion batteries is critical for reliable and efficient energy storage and usage. Traditional SOH estimation approaches either compromise on real-time performance or on estimation accuracy. This paper introduces an end-cloud collaboration approach that synergistically combines a cloud-based deep learning model with an end-based empirical model to achieve both high-accuracy and real-time SOH estimation. Utilizing the Transformer architecture, the cloud-side model employs multiple features extracted through signal analysis technology. On the other hand, the end-side employs a fast, iterative double exponential empirical model that provides real-time estimates. Two methods of end-cloud collaborative updating are presented, both leveraging Kalman Filter and Unscented Kalman Filter (UKF) to integrate and iteratively update the models. Evaluation shows that the cloud-side model achieves a Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) of around 0.8 %, while the end-cloud collaboration system maintains these metrics at 1 %, successfully capturing nonlinear capacity rebound phenomena. The work contributes to the domain by offering an approach that balances computational load and latency, making it suitable for online applications. Under the Cyber Hierarchy and Interactional Network (CHAIN) framework, this end-cloud collaboration architecture holds promise for high-accuracy, real-time health management of lithium-ion batteries across their full lifecycle.

Optimized energy management of a solar battery microgrid: An economic approach towards voltage stability

As the adoption of renewable energy sources (RESs) continues to surge, and the concept of microgrids (MGs) gains widespread recognition, the need for efficient battery energy storage system (BESS) management within MGs has become increasingly prominent. This paper introduces a novel Energy Management System (EMS) designed for grid-connected MGs, with the primary objectives of enhancing the energy economics of the MG, minimizing BESS degradation, and ensuring that the point of common coupling (PCC) voltage remains within prescribed limits. The proposed EMS utilizes a finite-horizon Model Predictive Control (MPC) framework to seamlessly coordinate BESS operations, encompassing charging, discharging, and reactive power provision. This coordination is done in conjunction with solar power generation, load demand, electricity pricing, and feed-in tariffs. Furthermore, the EMS accounts for uncertainties related to load and solar demand using a Monte Carlo simulation approach. The optimization goal of the proposed EMS is to minimize the expected total operational cost of the MG over a 24-hour prediction horizon. This cost encompasses both economic costs and battery degradation costs. The optimization process adheres to a set of constraints that consider BESS limitations, such as state of charge (SoC) constraints and charging/discharging limits, as well as inverter capacity limits and PCC voltage requirements. Conducting rigorous case studies on the MATLAB Simscape Electrical platform and validating them in real-time using the OPAL-RT simulator demonstrate the effectiveness of the proposed EMS across diverse operational scenarios and pricing models. The findings of these case studies provide valuable insights into the effectiveness of the EMS in real-world MG applications.

Layer-by-layer assembling redox wood electrodes for efficient energy storage

The exploration of redox-active organic materials and low tortuous thick-electrodes is attractive for energy storage. The in-situ valorized lignin on raw wood surface accompanied by layer-by-layer deposition of electro-active materials endow such spatially distributed wood electrodes with high specific capacitance. Here, we report a layer-by-layer assembled ca.1.5 mm-thick redox wood hybrid electrode with 20 mg cm-2 electro-active mass loading for efficient energy storage. The in-situ modified surface lignin in treated wood (TrW) holds promise as redox-active material with enriched nanoporosity, carbonyl functionalities, and multi-phase ionic transport structure. The carbon nanotubes (CNTs) networking with in-situ polymerized polypyrrole (PPy) nanorods three-dimensionally in the lumen of TrW afford a wool-like, highly porous nanostructure. Such a hierarchical structured PPy@CNTs@TrW electrode offers a high areal capacitance of 1.46 F cm-2 with an extraordinary energy density of 0.983 mWh cm-3 (3.68 Wh kg-1) and power density of 5.4 mW cm-3 (20.25 W kg-1). Here, the valorized surface lignin contributes contributes to electrochemical energy storage accompanied by spatially distributed PPy@CNTs in low tortuous electrodes. The electrode offers extremely low electrochemical impedance of 0.61 Ω electrode resistance and 1.57 Ω electrolyte resistance. The hybrid wood electrode showcases even higher conductivity and energy/power density than thin carbonized wood and other state-of-the-art thin electrodes made of highly conductive three-dimensional networks. This work highlights the potential of in-situ valorized lignin in developing high-performance eco-friendly thick-electrodes for electrochemical energy storage applications.

Designing strategically functionalized conjugated microporous polymers with pyrene and perylenetetracarboxylic dianhydride moieties with single-walled carbon nanotubes to enhance supercapacitive energy storage efficiency

We utilize straightforward and traditional Sonogashira coupling reactions to synthesize two conjugated microporous polymers linked with pyrene (referred to as PyT-PTCDA and PyT-PHTD CMPs) by combining the common precursor of 1,3,6,8-tetraethynylpyrene (PyT) with 1,7-dibromo-3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA-Br2) and 3,6-dibromophenanthrene-9,10-dione (PHTD-Br2). Various analytical techniques, including spectroscopy and microscopy, are employed to characterize these two PyT-CMP materials. The PyT-PTCDA CMP exhibits notable thermal stability (with a decomposition temperature of 351 °C and a char yield of 61 wt %). We combine the PyT-PTCDA and PyT-PHTD CMPs with exceptionally conducting single-walled carbon nanotubes (SWCNTs) through π-π stacking interactions between SWCNTs and PyT unit to improve their electrical conductivity and electrochemical performance. Electrochemical evaluations reveal that the PyT-PTCDA CMP/SWCNTs nanocomposite shows an impressive capacitance of 376 F g−1 (at 0.5 A g−1) in a three-electrode system. After undergoing 5000 cycles of charging and discharging, it maintained 98 % of its original capacitance while demonstrating an energy density of 52 Wh/kg. Additionally, in a symmetric coin cell system, the energy density is 17 Wh/kg and the capacitance is 119 F g−1 for PyT-PTCDA CMP/SWCNTs. This approach presents a promising avenue for developing high-performance supercapacitors by strategically blending PyT-CMPs with highly conductive SWCNTs.

Synergetic supercapattery: Stitching of cobalt zinc manganese oxide and polyaniline matrix for efficient energy storage applications

Optimizing energy storage performance requires the integration of both battery and supercapacitor advantages into a hybrid device. This study focuses on the strategic combination of positive (battery-like) and negative (electrical double layer, EDL) electrode materials in a single device, known as a supercapattery. Cobalt zinc manganese oxide (CZMO) ternary composite and polyaniline (PANI) are synthesized via hydrothermal and polymerization methods, respectively. The CZMO/PANI composite is prepared using a physical blending method. XRD and FTIR analyses confirmed the composition of CZMO/PANI, while surface morphological analysis (FESEM and HRTEM) demonstrated successful intercalation between CZMO nanorods and the PANI matrix. XPS and BET analyses are employed to examine the chemical composition and surface area of the composite. Electrochemical performance of CZMO, PANI, and CZMO/PANI is individually analyzed using a three-electrode system. It is evident that the CZMO/PANI composite exhibits a better specific capacity (340 C g−1) than CZMO and PANI. The two-electrode system (device), embodying CZMO/PANI as the positive electrode and activated carbon as the negative electrode, exhibits promising Specific energy 30.75 Wh kg−1 and specific power 820 W kg−1. Based on these results, it is evident that the CZMO/PANI composite will be a viable option for supercapattery applications.

Achieving high energy storage density and efficiency in (Na0.5Bi0.5)TiO3-based lead-free ceramics

Due to the demands of miniaturization, weight reduction and green development for electronic devices, development of lead-free dielectric ceramic capacitors with high recoverable energy density (Wrec) and energy storage efficiency (η) attracts much attention. To this end, (1-x)[0.75(Na0.5Bi0.5)TiO3-0.25SrTiO3]-xNdNbO4 (abbreviated as: NBST-xNN) ceramics were fabricated through a solid-state reaction method. After adding NN, the non-perovskite phase of Bi2Ti2O7 (BTO) with low dielectric constant (εr) and loss (tan δ) is generated. Finite element software (COMSOL) was used to explore the influence of the BTO phase on breakdown strength (Eb). The simulation result indicates that the BTO phase with a low εr concentrates a larger local electric field (LEF), and thus weakens the LEF loading in the main perovskite phase, which is beneficial for enhancing Eb. Moreover, NN doping significantly decreases the oxygen vacancy concentration in NBST ceramics, which plays a key role in improving Eb. On the other hand, as NN content increases, the hysteresis of the polarization (P)-electric field (E) loops is substantially suppressed, and the polarization saturation is delayed, which can be ascribed to the appearance of the BTO phase having a linear dielectric characteristic and to the enhanced fluctuations of composition and charge by NN doping. Benefitting from the above factors, the optimal energy storage performance (ESP) with a Wrec of 4.14 J/cm3 and an η of 90 % is obtained in NBST-0.08NN ceramics. Meanwhile, the ESP of NBST-0.08NN ceramics shows good charge-discharge properties and thermal stability. In conclusion, these results demonstrate that NBST-0.08NN ceramics are promising candidates as environment-friendly dielectric capacitor materials.

Ultrahigh energy storage density and efficiency in A/B-site co-modified silver niobate relaxor antiferroelectric ceramics

AgNbO3-based antiferroelectric ceramics can be used to prepare dielectric ceramic materials with energy storage performance. However, their efficiency is much lower than that of relaxors, which is one of the biggest obstacles for their applications. To overcome this problem, AgNbO3 ceramics co-doped with Eu3+ and Ta5+ at the A- and B-sites were prepared in this work. The Ag0.97Eu0.01Nb0.85Ta0.15O3 sample has a Wr of 6.9 J/cm3 and an η of 74.6%. The ultrahigh energy storage density and efficiency of Ag0.97Eu0.01Nb0.85Ta0.15O3 has been ascribed to the synergistic effect of the increase in the breakdown electric field, the enhancement of antiferroelectric stability, the construction of multiphase coexistence, and the modification of the domain structure morphology. The Ag0.97Eu0.01Nb0.85Ta0.15O3 ceramic is expected to be one of the options for preparing dielectric capacitors.

Strong magnetodielectric effect in Bi(La)Fe(Cr)O3 multiferroic nanomaterials

The Bi1-xLaxFe1-yCryO3 (x= 0.00, 0.06; y= 0.00, 0.03, 0.06, 0.09, 0.12) nanomaterials have been synthesized using the simple solvo-thermal technique. The Rietveld refinement of XRD analysis using FullProf Software confirms that all synthesized materials follow rhombohedral perovskite crystal structure of R3C space group. The dielectric and ac conductivity data are analyzed to understand the role of grain and grain boundary contributions. The enhancement of magnetic properties has been observed from SQUID measurement for the co-doped samples at room temperature. Also, a significant improvement in polarization has been observed for the doped nanocompounds from the ferroelectric hysteresis loop. The magneto-dielectric study reveals a large improvement in our co-doped BFO nanomaterials and the value is nearly three times of those reported earlier. The calculated energy storage efficiency for the co-doped samples are found to have as high as 51%. The sample with x= 0.06 and y= 0.09 with a magneto dielectric coefficient of around 30% and energy storage efficiency of 35% is the most suitable for both spintronic and energy storage devices.

Excellent energy storage properties and multi-scale regulation mechanism of Sr(Zr0.5Ti0.5)O3-(Na0.5Bi0.5)0.94Ba0.06TiO3 ceramics

With the rapid advancement of energy storage technologies, dielectric capacitor materials with the outstanding recoverable energy density and power density have garnered significant attention from researchers in the past decades. In this study, (1-x) (Na0.5Bi0.5)0.94Ba0.06TiO3-xSr(Zr0.5Ti0.5)O3 ceramics were prepared via a solid-state reaction method, and the impact of composition on their structure, energy storage performance and stability were investigated. The results revealed that the introduction of Sr(Zr0.5Ti0.5)O3 induced the ferroelectric-relaxor transformation of (Na0.5Bi0.5)0.94Ba0.06TiO3 ceramics, leading to the destruction of the long-range ferroelectric order and the formation of polar nanoregions. In addition, the 0.7(Na0.5Bi0.5)0.94Ba0.06TiO3–0.3Sr(Zr0.5Ti0.5)O3 ceramic exhibited the optimal comprehensive energy storage performance: its recoverable energy storage Wrec attained 8.19 J/cm3 at 650 kV/cm, while the energy storage efficiency η was 85.6 %. Meanwhile, it displayed exceptionally high power density (315.7 MW/cm3) and charge-discharge rate (t0.9 = 50.4 ns). Moreover, this ceramic demonstrated the impressive energy storage performance, in particular, good temperature stability across a wide range of temperatures (20–140 °C), frequency stability (1–200 Hz), and fatigue resistance (1–106 cycles). Finite element analysis showed an enhancement in the breakdown field strength of the ceramics was attributed to the reduction in grain size. First-principles calculations revealed that the band gap increased after adding Sr and Zr elements, and the interactions between the states of O 2p and Ti 3d, Zr 3d, Bi 6p may serve as the microscopic origin of electron energy level polarization and enhanced dielectric performance. Thus, the ceramics have great potential for the application in high-power pulsed electronic systems.

(Ag0.80Bi0.04Sr0.04)(Nb1-xTax)O3 ceramics with enhanced energy storage for high-temperature application via synergic optimization

Dielectric capacitors with high power density are essential components in advanced electronic and micro-electronic products. Nevertheless, the limited energy storage density and efficiency, coupled with poor performance at elevated temperatures, severely restrict their usefulness. In this work, Ta was introduced to the (Ag0.80Bi0.04Sr0.04)NbO3 ceramic prepared via the hydrothermal-synthesized powders to improve the room- and high-temperature energy storage performance. A large breakdown strength of 729kV/cm, a high recoverable energy storage density of 8.5J/cm3 and a benign energy efficiency of 75.6% were simultaneously achieved in (Ag0.80Bi0.04Sr0.04)(Nb0.85Ta0.15)O3 ceramics. Moreover, the larger energy storage efficiency (83.5%) at elevated temperatures than room temperature, the benign frequency and cycle stability foreshow great potential in realizing the application of capacitors at high-temperatures.

Modeling of heat and solute transport in a fracture-matrix mine thermal energy storage system and energy storage performance evaluation

Repurposing groundwater-filled mine cavities for thermal energy storage has demonstrated promising potential to buffer the imbalance of energy supply and demand. Fractured formations are widespread in old mines due to previous excavation activities, which dominates the performance and efficiency of the mine thermal energy storage (MTES) system. Therefore, understanding the mechanisms of fluid flow, heat, and solute transport in fractured reservoirs in the MTES system is essential for its application and the assessment of environmental impact. In this study, fluid flow, heat, and solute transport in a 3D fracture-matrix MTES system are modeled simultaneously based on site-specific data in Freiberg, Germany. The simulations are conducted with a coupled Hydro-Thermo-Component process newly developed in the open-source software OpenGeoSys (OGS). To stabilize the simulation in the fracture-matrix hybrid system, a flux-corrected transport scheme is specifically implemented and applied in the model. Thus, heat and mass exchange between the embedded fractures and the matrix in the formation of MTES can be accurately simulated on the basis of the conforming mesh. In a hypothetical short-term scenario of a 15-day heating and cooling cycle of the MTES operation, the solute is transported faster than the heat in the fractured formation, indicating that disturbance of mineral compositions in the original mine water can affect a larger region than heat. The embedded fracture network in the surrounding formation is also found to increase the thermal energy storage capacity by 44%, while decreasing the recovery ratio by 14% compared to those of the unfractured formation. More energy will be transported and stored in the more fractured formation from heated mine water, but less energy can be recovered. The behavior of the MTES system strongly depends on local geology and hydraulic conditions and therefore needs to be evaluated in a site- and application-specific manner. This study provides preliminary insights into the performance and efficiency, as well as the environmental impact of the MTES operation in the short term.

Surface plasma treatment boosting antiferroelectricity and energy storage performance of AgNbO3 film

The utilization of AgNbO3 film in dielectric energy storage poses challenges due to its susceptibility to impurity phase formation, which compromises its antiferroelectric properties and breakdown electric field. In this study, we successfully fabricated an AgNbO3 film with outstanding antiferroelectric properties and energy storage capabilities by employing oxygen ion surface plasma technology in conjunction with the sol-gel method. Our results demonstrate that the surface of the AgNbO3 film undergoes a layer-by-layer treatment using oxygen ion plasma, effectively suppressing impurity phases and oxygen vacancies formation while reducing grain size and enhancing insulation performance. The AgNbO3 film, which has undergone surface plasma treatment with oxygen ion, exhibits exceptional characteristics as an antiferroelectric material by demonstrating an impressive energy storage density of 13.13J/cm3 and a high energy storage efficiency of 56%. Overall, we present a straightforward and viable approach for fabricating high-performance AgNbO3 films for efficient dielectric energy storage.

High energy storage performance induced by the introduction of BiScO3 into (Bi0.5Na0.5)TiO3–BaTiO3 lead-free ferroelectric ceramics

In this work, ternary 0.25(Bi0.5Na0.5)TiO3-(0.75-x)BaTiO3-xBiScO3(abbreviated as 0.25BNT-(0.75-x)BT-xBS, x = 0.19, 0.21, 0.23, 0.25, 0.27) lead-free ferroelectric ceramics were synthesized using the solid-state reaction method. The introduction of BiScO3 into (Bi0.5Na0.5)TiO3–BaTiO3 ceramics had a significant impact on changing the phase structures, and microstructures, as well as the dielectric and ferroelectric properties. All ceramics exhibited a coexistence of tetragonal(P4bm) and rhombohedral(R3c) perovskite phases, while the influence of the BiScO3(BS) content on the average grain size was not significant. Slim polarization-electric field hysteresis loops were recorded for the 0.25BNT-(0.75-x)BT-xBS ceramics, with low remnant polarization (Pr) and large maximum polarization(Pmax). 0.25BNT-0.50BT-0.25BS ceramic had the largest Pmax, which induced a high energy storage density of 2.93 J/cm3 and energy storage efficiency of 91 % under a low electric field of 230 kV/cm 0.25BNT-0.50BT-0.25BS ceramic not only yielded excellent fatigue resistance, but also maintained good energy storage performance at high temperature and high frequency, which are considered of great importance since they can be leveraged for the potential development of high temperature and frequency capacitors. In addition, an excellent pulse performance was measured, with a high discharge energy density of 3.42 J/cm3 and a fast discharging rate t0.9 of 130 ns. This good pulse performance was maintained at high temperatures, suggesting that the proposed material is also highly competitive for applications where high-temperature pulse devices are required.