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As newly emerging energy storage devices, supercapacitors are being investigated thoroughly by researchers. Free-standing electrode is one of the major research focuses in this area, which not only avoids the use of resistive binders but also simplifies device assembly. The study describes the synthesis and study of carbon fiber-based carbon carbon composite paper (heat treated to different temperatures) as a free-standing supercapacitor electrode. Due to the inert nature of carbon paper, it was activated to create defect sites and to increase the specific surface area. Electrochemical studies suggested that activated carbon paper heat treated to 750°C (ACP-750) exhibited the highest areal capacitance of 11.4 F/cm2 (422.2 F/g) at the current density 2.5 mA/cm2 (0.09 A/g), probably due to the generation of larger number of defect sites (as depicted by XRD and RAMAN studies). ACP-750 electrode was used to fabricate the solid-state symmetric supercapacitor device that exhibited an energy density 0.77 Wh/cm2 at a power density of 2.34 W/cm2. The electrode was allowed to age (ACPA-750), after which it exhibited enhanced specific capacitance of 16.8 F/cm2 (622.2 F/g) at a current density 2.5 mA/cm2. ACPA-750//ACPA-750 device delivered maximum energy density of 1.66Wh/cm2 at a power density of 3 W/cm2. The device exhibited a coulombic efficiency of 96.1% and capacitance retention of 89% after 10,000 cycles. Carbon paper was activated to produce defect sites and to enhance the specific surface area because of its inert nature. The effect of ageing can be observed by the enhancement in the specific capacitance value of 16.8 F/cm2 (622.2 F/g) at 2.5 mA/cm2. At a power density of 3 W/cm2, the ACPA-750//ACPA-750 symmetrical supercapacitor device achieved a maximum energy density of 1.66 Wh/cm2 along with 89 % of initial capacitance retention after 10,000 charge-discharge cycles. [Display omitted] • Carbon paper was developed as free standing supercapacitor electrode. • Activation of carbon paper enhanced the defect sites and the surface area. • A solid-state supercapacitor device was fabricated using activated carbon paper. • The device delivered an energy density of 1.66Wh/cm2 @ 3 W/cm2 power density. • After 5000 cycles devices coulombic efficiency is 98.3%, capacity retention is 95%. [ABSTRACT FROM AUTHOR]

In the quest for greener and more efficient energy storage solutions, the exploration and utilization of renewable raw materials is essential. In this context, cellulose-derived separators play a central role in enhancing the performance of green energy storage devices. However, these often exhibit disadvantageous porosity and limited wet strength. Here, we demonstrate a facile approach to tailor thickness (ca. 40 μm), air permeability (0.1–200 cm3 s−1), and mechanical properties of separators by integration of up to 50 wt% microfibrillated cellulose (MFC) into paper sheets. While the MFC enhanced the formation of dense networks, these separators show a poor dimensional stability (folding and creasing) concomitant with a low strength under wet conditions, crucial for assembly and operation. Crosslinking with 1,2,3,4-butanetetracarboxylic acid (BTCA) however, led to an increase in wet strength by up to 6700 % while ensuring dimensional stability. The electrochemical performance, evaluated by impedance spectroscopy and galvanostatic cycling (7500 repetitions) showed comparable results as commercially available glass and polypropylene separators in terms of ion diffusion, charge-discharge rate performance, Ohmic loss and capacitance retention %. The approach demonstrates that disadvantages of paper-based separators in terms of dimensional stability and wet strength can be overcome by a paper technological approach using crosslinking strategies. [Display omitted] [ABSTRACT FROM AUTHOR]

The reuse of waste papers by conversion into valuable carbon materials has received considerable attention for diverse applications such as energy storage and water purification. However, traditional methods for converting waste papers into materials with suitable properties for specific applications are often complex and ineffective, involving consecutive carbonization and activation steps. Herein, we propose a simple one-step microwave (MW)-assisted synthesis for preparing waste paper-derived porous carbons (WPCs) for energy storage and water purification. Through a 30-min synthesis, WPCs with graphitic structure and high specific surface area were successfully produced. The fabricated WPCs exhibited outstanding charge storage capability with a maximum specific capacitance of 237.7 F g−1. Additionally, the WPC demonstrates a high removal efficiency for various dyes, achieving a maximum removal efficiency of 95.0% for methylene blue. The developed one-step MW synthesis not only enables the production of porous carbon from waste paper, but also offers a viable approach to address solid waste management challenges while simultaneously yielding valuable materials. [Display omitted] • Waste paper-derived porous carbons were synthesized by one-step microwave synthesis. • Within 30-min MW synthesis, graphitic and high-surface area WPCs were produced. • WPC exhibits outstanding electrochemical capacitance of 237.7 F g−1. • WPC exhibits high removal of various dyes, with maximum of 95.0% for methylene blue. [ABSTRACT FROM AUTHOR]

Lithium-sulfur batteries (LSBs) are gaining attention as a potential energy storage option due to their impressive theoretical specific capacity. However, the main challenges hindering its implementation include the expansion in volume of sulfur and lithium sulfide during the conversion process of charge-discharge, the limited conductivity of the active material, and specifically, the phenomenon known as shuttle effect caused by lithium polysulfides (LiPSs). The development of high-performance LSBs have led to the need for self-supporting cathode materials that can efficiently accommodate volume expansion, build up efficient conductive pathways, and suppress shuttle effects. The poly(3,4-ethylenedioxythiophene) (PEDOT) was synthesized in situ on cellulose nanofibers (CNFs), resulting in the formation of CNF@PEDOT. Subsequently, CNF@PEDOT was combined with plant fibers (PFs) and multi-wall carbon nanotubes (MWCNTs) to fabricate a self-supporting cathode featuring a multi-scale network structure denoted as CNF@PEDOT/MWCNT/PF/S. The PFs serve as the primary backbone network, CNF@PEDOT to form the secondary conductive network, and MWCNTs act as tertiary conducting networks. In fact, the design of multi-level conductive network effectively improves the conductivity of the material, and PEDOT can further adsorb and catalyze LiPSs. The incorporation of PFs significantly enhanced the mechanical robustness of the cathode and augmented its electrolyte permeability. The self-supporting CNF@PEDOT/MWCNT/PF/S cathode exhibits an initial capacity of 1204.6 mA h g−1 when loaded with 2.4 mg cm−2 of sulfur at a rate of 0.2 C. Notably, it maintains an initial discharge specific capacity of 712.9 mA h g−1 even when the sulfur load is increased to 4.3 mg cm−2. This study presents a comprehensive framework for the development of self-supporting cathodes in LSBs. [Display omitted] • The self-supporting cathode with multi-scale network structure has been fabricated by the papermaking process. • The copious hydrogen bonds furnished by plant fibers enhance the mechanical characteristics of the material. • The efficient conductive network was formed in a self-supporting cathode by in situ polymerization of PEDOT on CNFs. • The CNF@PEDOT network with a high aspect ratio exposure of -S- functional groups for efficient anchoring of polysulfides. • The incorporation of rich multi-scale conductive network significantly improves the conductivity of cathode materials. [ABSTRACT FROM AUTHOR]

Along with the developing of flexible electronics, there is a strong interest in high performance flexible energy storage materials. As natural carbohydrate polymer, cellulose fibers have potential applications in the area due to their biodegradability and flexibility. However, their conductive and electrochemical properties are impossible to meet the demands of practical applications. In this study, cellulose fibers were combined with polyaniline to develop novel paper-based supercapacitor electrode material. Cellulose fibers were firstly coordinated to Cu(II) and subsequently involved in polymerization of polyaniline. Not only the mass loading of polyaniline was significantly increased, but also an impressive area specific capacitance (2767 mF/cm2 at 1 mA/cm2) was achieved. The developed strategy is efficient, environmentally friendly, and has implications for the development of cellulosic paper-based advanced functional materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Organic molecule stabilized manganese stannate (MnSnO 3) perovskite nanoparticles were synthesized using a complexion strategy route. The Rietveld refinement analysis confirmed the formation of orthorhombic structure of manganese stannate with the space group of Pnma. Free standing manganese stannate electrode was fabricated on paper based flexible substrate and investigated the electrochemical performances. The maximum specific capacitance and areal capacitance delivered by electrode were ∼ 183 F/g and ∼ 487 mF/cm2, respectively, at the current density of 0.2 A/g, with an excellent capacitance retention ∼ 93% for 103 cycles at 0.6 A/g. A symmetric supercapacitor was fabricated using the MnSnO 3 as active material on positive and negative electrodes in solid state gel electrolyte configuration. The device achieved the specific capacity value ∼ 156 mAh/g at 0.1 A/g with the energy density and power density of ∼ 10 Wh/kg and ∼ 22 kW/kg, respectively, at 0.5 A/g. These results suggested that manganese stannate nanoparticles are promising candidates for high-performance supercapacitor application. [Display omitted] • Organic molecule stabilized manganese stannate perovskite nanoparticles. • Flexible Au-coated paper based free-standing electrode and symmetric device were fabricated for supercapacitor applications. • Diffusive control mechanism dominated the overall charge storage process. • The fabricated device exhibited excellent stability for energy and power storage performance. [ABSTRACT FROM AUTHOR]

• Three-dimensional WO 2 /MoO 2 @P, N-CNTs were prepared by the Self-template method. • Highly conductive and hollow structure of WO 2 /MoO 2 @P, N-CNTs avoided aggregation of NiCo-LDH. • IMSC devices were prepared by fully screen-printed technology. • IMSCs demonstrated excellent energy density (0.0590 mWh cm−2), cycling stability (100% capacity retention after 10,000 cycles) and mechanical stability (lighting the bulb under extremely distorted conditions). In-plane micro-supercapacitors (IMSCs) have greater promise for use in flexible wearable electronics than traditional stacked configurations due to their ease of integration and conformability. Nickel-cobalt layered double hydroxide (NiCo-LDH) has garnered significant interest as a stellar material for supercapacitors because of its affordable price, regular morphology, and high theoretical capacity. Unfortunately, the intrinsic poor conductivity of LDH materials prevents supercapacitors from achieving long-term stable cycling and the desired energy density. This research successfully applies the self-templated approach to prepare carbon nanotubes (CNTs) with heterogeneous architectures and numerous phase interfaces, thereby mitigating this disadvantage. Carbon nanosheets adorned with WO 2 and MoO 2 nanoparticles assemble the CNT with a typical three-dimensional structure. When combined with LDH in a suitable ratio, the composite electrode's conductivity significantly improves, providing increased capacity and cycling stability. Compared to commercial CNTs, the larger size of the prepared WO 2 /MoO 2 @P, N-CNTs serves a superior supporting and connecting role, thereby preventing the NiCo-LDH from aggregating. Under the best conditions, the composite electrode demonstrates a capacity of 1237 C/g at 1 A g−1 and an optimal capacity retention of more than 92%. For the IMSC devices, the composite materials as the positive electrode achieve an energy density of 0.0590 mWh cm−2, and no capacity degradation is observed after 10,000 cycles. In addition, bending tests have demonstrated the mechanical stability of the IMSCs. Therefore, this strategy of mixing highly conductive WO 2 /MoO 2 @P, N-CNTs can effectively improve the conductivity of the composite material and the mechanical properties of the overall device. Furthermore, this concept can be further extended to the preparation and application of other wearable devices. [ABSTRACT FROM AUTHOR]

A very efficient and environmentally friendly supercapacitor using carbon paper and onion-like carbon has been developed. [Display omitted] • A metal-free supercapacitor with onion-like carbon, offering a greener and efficient energy storage alternative. • The carbon paper current collector outperforms the traditional aluminium metal foil in an organic electrolyte system. • A water-based spray coating process enables sustainability and scalability. • A lightweight, resource-efficient system architecture advances sustainable energy storage. Supercapacitors will play a crucial role in the future energy landscape due to their high power density and extended cycle stability. However, energy density tends to be relatively low, partly because of conventional heavy current collectors, also posing sustainability issues. It is crucial to integrate lightweight, flexible current collectors and environmentally friendly active materials while maintaining the performance of the supercapacitor. Here we report on a metal-free supercapacitor using a carbon paper current collector and onion like carbon (OLC). The electrodes were fabricated through a scalable and flexible spray-coating process using onion-like carbon ink. Higher capacitances were observed for the paper-based electrode (24.1 F/g, 34.9 mF/cm2) compared to 22.5 F/g (31.5 mF/cm2) for aluminium collectors at scanrates of 2.5 mV/s over a voltage window of 2.5 V. At elevated scanrates of 100 mV/s–5 V/s, the actual operating window of a supercapacitor, the paper-based electrode offers a significantly enhanced performance. Stability tests demonstrated a capacitive retention of 98 % for both electrodes after 10,000 cycles. The utilization of onion-like carbon as the active material and a paper-based current collector enables the development of a fully carbon-based supercapacitor system, without compromising its electrochemical performance. This approach introduces a metal-free OLC supercapacitor and promotes environmental sustainability by reducing the dependence on conventional metal-based components and provides a more resource-efficient solution to address the energy storage needs. [ABSTRACT FROM AUTHOR]

Hydrogen fuel is a non-toxic and source-abundant energetic system, but for its applications in the industry, several issues related to its storage must be resolved. Compounds like NaBH 4 appear as promising hydrogen sources, while can release the latter rapidly under controllable conditions with the use of heterogeneous catalyst systems. In this work, we synthesized a Ni–CoP catalyst by electrodeposition in a three-step process on carbon paper as support. The materials were characterized via SEM-EDS, XRD, and XPS techniques, while the hydrogen evolution reaction (HER) from alkaline NaBH 4 solutions was tested as a batch experiment. Ni–CoP catalyst showed a high amount of H 2 generated in a short time (∼550 mL in 1 min) and remained at 78 and 54% of its initial performance after respectively 100 and 300 h of a continuous hydrolysis process. Our catalyst revealed exceptional performance and stability at higher temperatures and a long process time, which have been a rare subject of investigation in other reports for NaBH 4 hydrolysis in the past. This work paves a new perspective in studying catalysts for hydrogen generation from borohydrides. [Display omitted] • Ni–CoP catalyst was electrodeposited on a carbon support. • Material characterization proved the formation of desired active layers. • High efficiency and stability of the catalyst for a long-term NaBH 4 hydrolysis was revealed. [ABSTRACT FROM AUTHOR]

Dielectric capacitors are commonly used in electronic and electric power systems due to their excellent charging and discharging rates and ultra-high power densities. Especially, with the rapid development of new energy vehicles industry, high-temperature films capacitors are urgently needed, while the conductivity loss of polymer capacitive films at high temperatures sharply increases, which should be significantly suppressed for achieving excellent energy storage performance. This paper presents a composite film with polyetherimide (PEI) as the matrix, and core-shell structured particle ceramic as fillers where high polarization of barium strontium titanate (BaSrTiO 3) as the core and excellent insulation strength of alumina (Al 2 O 3) as the shell, respectively, achieving a synergistic enhancement of breakdown strength and dielectric constant of Al 2 O 3 @BaSrTiO 3 /PEI composite film. More importantly, the Al 2 O 3 layer with moderate dielectric constant can effectively relieves the electric field distortion at the interfacial regions due to the large difference between BaSrTiO 3 fillers and PEI matrix. The composite film demonstrates exceptional thermal and cycling stability, as well as energy storage properties within the studied temperature range, a discharge energy density of 4.67 J/cm3 at 150 °C. The enhanced mechanism of energy storage performance is revealed bycomparatively analyzing of the microstructure and dielectric properties of BaSrTiO 3 /PEI, Al 2 O 3 /PEI, and Al 2 O 3 @BaSrTiO 3 /PEI composite films. This paper presents a modification strategy of inorganic/organic composite films by increasing both of dielectric constant and electric breakdown strength at elevated temperature. [ABSTRACT FROM AUTHOR]

Hydrogen is emerging as a critical player in transitioning to sustainable and renewable energy systems, serving roles in energy storage, grid balancing, and decarbonization. This paper explores various aspects of hydrogen, including its production through renewable-electricity-driven electrolysis, advanced storage techniques, and incorporation into current energy systems. It highlights primary electrolysis methods like PEM and alkaline, noting their improved efficiency and cost-effectiveness. Various hydrogen storage methods, such as physical, chemical, and advanced porous materials, are examined for their benefits and limitations. The review further explores hydrogen's integration into grid storage systems and microgrids to enhance energy reliability. It discusses hydrogen's application in fuel cells for electricity generation, focusing on technological advancements that improve efficiency and reduce costs. Additionally, the paper underscores hydrogen's crucial role in reducing CO 2 emissions in industrial processes like steel production and its use in residential and commercial energy supply through combined heat and power systems. Economic aspects and supportive policies from regions are analyzed, highlighting the global efforts and policies supporting the potential hydrogen in renewable energy systems. This analysis emphasizes hydrogen's comprehensive role in enhancing renewable energy systems and achieving global sustainability objectives, providing a thorough review of recent progress and challenges. • Identifies PEM and alkaline as efficient electrolysis methods. • Analyzes varied H 2 storage options for mobility and stationarity. • Highlights advancements in H 2 fuel cells for vehicles. • Discusses global policies supporting H 2 integration. • Reviews economic impacts of scaling H 2 infrastructure. [ABSTRACT FROM AUTHOR]

This paper considers an electric-hydrogen hybrid energy storage system composed of supercapacitors and hydrogen components (e.g., electrolyzers and fuel cells) in the context of a microgrid with photovoltaic generators. To manage the power and hydrogen flows within the microgrid and coordinate the coupling between the microgrid and a hydrogen refueling station, this paper proposes an energy management framework. The outer layer of the framework takes the hydrogen compressor power as part of the microgrid load and optimizes the hydrogen flow from the microgrid to the hydrogen refueling station. The inner layer develops a two-stage scheme to optimize the power allocation between the electric and hydrogen systems within the microgrid. A low pass filter with an adaptive cutoff frequency is utilized to split the net load power of the microgrid into high-frequency and low-frequency components, which are then assigned to the electric and hydrogen systems, respectively. The adaptive cutoff frequency is determined based on the power split factor tuned twice during the two stages of the power allocation scheme based on the supercapacitor state of charge. The effectiveness of the proposed framework is validated by performing real-time simulations using a dSPACE platform. • Proposes an energy management framework for electric-hydrogen systems. • Optimizes the hydrogen flow from the microgrid to the hydrogen refueling station. • Develops a two-stage power allocation scheme based on artificial potential field. • Validates the framework using a dSPACE DS1202 real-time simulation system. [ABSTRACT FROM AUTHOR]

Transitioning to a sustainable energy future necessitates innovative storage solutions for renewable energies, where hydrogen (H₂) emerges as a pivotal energy carrier for its low emission potential. This paper explores unlined rock caverns (URCs) as a promising alternative for underground hydrogen storage (UHS), overcoming the geographical and technical limitations of UHS methods like salt rock caverns and porous media. Drawing from the experiences of natural gas (NG) and compressed air energy storage (CAES) in URCs, we explore the viability of URCs for storing hydrogen at gigawatt-hour scales (>100 GWh). Despite challenges such as potential uplift failures (at a depth of approximately less than 1000 m) and hydrogen reactivity with storage materials at typical conditions (below temperatures of 100°C and pressures of 15 MPa), URCs present a flexible, scalable option closely allied with green hydrogen production from renewable sources. Our comprehensive review identifies critical design considerations, including hydraulic containment and the integrity of fracture sealing materials under UHS conditions. Addressing identified knowledge gaps, particularly around the design of hydraulic containment systems and the interaction of hydrogen with cavern materials, will be crucial for advancing URC technology. The paper underscores the need for further experimental and numerical studies to refine URC suitability for hydrogen storage, highlighting the role of URCs in enhancing the compatibility of renewable energy sources with the grid. • Detailed exploration of unlined rock cavern (URC) technology. • Analysis of URCs' potential for large-scale hydrogen storage. • Insights from historical use of URCs in compressed gas storage. • Examination of the opportunities and challenges in using URCs for hydrogen storage. [ABSTRACT FROM AUTHOR]

The paper is devoted to the development of a device for protecting facilities with turn-to-turn insulation, namely transformers and wind generators in order to increase the reliability of operation of electrical power systems, renewable energy installations and energy storage systems. The paper presents the results of experimental studies of the parameters of a prototype frequency-dependent device, as well as an assessment of the effectiveness of suppression of high-frequency surge voltages by the proposed device. The results of four groups of measurements are shown, which were compared with each other and with the results of previously showed computer simulations. The high efficiency of the proposed device when influencing the slope and amplitude of short high-frequency transients is shown. It is indicated that the parameters proposed earlier in the simulation allow the device to be used effectively. A brief analysis of alternative methods and means of protection is provided, and the prospects for using the device as protective equipment for wind power plants are also considered. [ABSTRACT FROM AUTHOR]

This paper explores green hydrogen-based carbon dioxide (CO 2) hydrogenation for the production of oxygenates, presenting it as a pivotal strategy for mitigating carbon emissions and advancing sustainable energy solutions. The conversion of CO 2 into oxygenates through hydrogenation emerges as a promising avenue, particularly in the context of transportation applications where the storage of hydrogen poses challenges. The substitution of fossil diesel and gasoline fuels with green hydrogen-derived dimethyl ether, or methanol/ethanol, is advantageous from a life cycle analysis (LCA) CO 2 emission perspective even without the capture of the CO 2. However, the greatest sustainability appeal is contingent on the crucial aspect of capturing CO 2 when utilizing these fuels, which is an aspect currently absent in the literature. This narrative review comprehensively explores catalytic processes, mechanisms, sustainability perspectives, and the current state of research in this evolving area. It encompasses both the production of oxygenates through CO 2 hydrogenation and the subsequent utilization of these oxygenates in fuel cells or combustion systems, emphasizing the integration of CO 2 capture technologies. The paper contributes to the discourse surrounding the environmental and technological dimensions of energy storage ecosystems, providing a holistic view of their potential to foster sustainable energy solutions. [ABSTRACT FROM AUTHOR]

Ice storage sphere systems are favored in the field of energy storage, however, the poor thermal conductivity of phase change materials (PCM) seriously weakens their wide application. Metal foam has been shown to enhance its heat transfer. In this paper, we investigate the impact of varying the filling radius ratio of foam metal to further improve energy storage performance and reduce costs in ice storage spheres. Computational fluid dynamics are employed to analyze the heat transfer and solidification processes. The enthalpy-porosity method is used to describe PCM solidification, while the local equilibrium thermal (LET) model characterizes heat transfer between the PCM and foam metal. The study explores temperature field variations, solid phase fraction changes, solidification times, and cold storage volumes, accounting for natural convection. By comparing solidification rates and other relevant parameters, the effect of foam metal filling on the solidification process is explored. Moreover, a new evaluation index is proposed, which can assess the overall performance of ice storage systems in real-time, considering market prices. The results show that natural convection is the primary heat transfer mode in pure PCM-ffild ice storage spheres, whereas smaller foam metal filling radii significantly inhibit natural convection, resulting in heat conduction as the dominant mode. Without specific requirements, an optimal fill radius ratio of 9/13 is determined. This paper offers a comprehensive understanding of cold storage employing various foam metal filling radios, contributing to advancements in efficient thermal energy storage systems. [ABSTRACT FROM AUTHOR]

With the rapidly evolving geo-political landscape and unceasing advancements in technology, sustainable energy security is a very important topic. Research indicates that electrochemical energy systems are quite promising to solve many of energy conversion, storage, and conservation challenges while offering high efficiencies and low pollution. The paper provides an overview of electrochemical energy devices and the various optimization techniques used to evaluate them. The optimization techniques include linear regression, factorial design, the Taguchi method, artificial neural networks, filters, and a combination of such methods to improve these systems. To support the growing interest in research, the bulk of this study focuses on a review of the most promising and highly researched electrochemical energy devices, such as fuel cells, batteries, and supercapacitors. The paper also provides modest commentary on hydrogen production technologies, electrochemical reactors, and membrane separation technologies, amongst other technologies. Building on a previous paper by the authors of this paper on artificial intelligence in hybrid renewable energy systems with fuel cells, this work provides a comparative review of optimization techniques for supercapacitors by highlighting key findings based on model accuracy. A summary of the advantages and disadvantages of the different major optimization techniques is presented. The paper concludes that a combination of optimization techniques is used to overcome the drawbacks of individual techniques, with adaptive filters being the most widely studied. This paper presents studies on the Design of Experiments (DoE) with the goal of building a better understanding of the relationships that exist between different operating variables in various electrochemical devices. • The electrochemical systems can be optimized for better performance with high accuracy. • The optimization techniques used are either model-based or data-driven. • Linear regression and artificial neural networks are the most common techniques studied. • Hybrid models could be applied to enhance systems' accuracy and minimize errors. [ABSTRACT FROM AUTHOR]

The development of large energy systems based on renewable energy sources is accompanied by an increase in the input capacities of large grid storages. Taking into account the vector for decarbonization and maneuverability, the use of hydrogen as a fuel in the cycle of a diabatic compressed air energy storage (CAES) is a promising scientific and technical direction. This paper analyzes the key performance indicators of a compressed air energy storage in the presence and absence of thermal energy recovery within the cycle. In addition, an assessment was made of the prospects for the use of a methane-hydrogen mixture in gas turbines. At the end of the paper, a calculation of the process of plasma pyrolysis of methane is given as one of the possible methods for the production of hydrogen for use in energy purposes. [ABSTRACT FROM AUTHOR]

Biodegradable energy storage devices are being developed for real-time monitoring of biometric data, medical diagnosis, prognosis, and therapeutic uses due to the rising need for energy storage devices in biomedical and information technologies. In this review, we have briefly discussed the environment-friendly and biodegradable electrode materials in supercapacitors, batteries, supercapattery, and skin-patchable devices. The charge storage mechanism, biocompatibility, and safety of electrode material are discussed in detail. The electrode material based on carbon, metal, and organic patchable composites is studied. Furthermore, the most essential and core part of this review is discussing the several synthesis methodologies of biological environments and how these biodegradable materials fit into the architecture of energy storage devices. Lastly, this review paper gives a deep understanding of (biodegradable and environment-friendly electrode materials) in the current energy storage systems, challenges, and research directions. [ABSTRACT FROM AUTHOR]

This paper reports an extensive investigation on the structural, dielectric, ferroelectric and pyroelectric properties of 0.7Ba 1-x Sr x TiO 3 – 0.3Bi 0.5 Na 0.5 TiO 3 (x = 0.0, 0.5, 0.6, 0.7) ceramics synthesized via conventional solid-state reaction (SSR) technique. X-ray diffraction data confirms the presence of pure perovskite phase. The variation of lattice parameters with strontium concentration in 0.7Ba 1-x Sr x TiO 3 – 0.3Bi 0.5 Na 0.5 TiO 3 ceramics were evaluated using the Rietveld refinement of the XRD data. The variation of dielectric permittivity with temperature (ε' ∼ T) shows the diffused phase transition and all the parameters related to the relaxor ferroelectrics (relaxation coefficient, activation energy and freezing temperature) were evaluated. The energy storage properties of the as-prepared ceramics were evaluated using the room temperature PE loop. Amongst the as-prepared ceramics, the composition with x = 0.5 possesses the highest energy storage density of 0.46 J/cm3 with an efficiency of 90 %. The temperature dependent P-E loops were used to study the electrocaloric effect (ECE). The ECE calculations were performed using in-direct method based on Maxwell's thermodynamic relations. A maximum adiabatic temperature change of 0.32 K is achieved at 268 K under a small applied electric field of 25 kV/cm for the ceramic with Sr content x = 0.5. Additionally, electrocaloric responsivity ξ max = 0.13 K mm/kV was also found for the studied ceramics. The above results show that the ceramic 0.7Ba 1-x Sr x TiO 3 – 0.3Bi 0.5 Na 0.5 TiO 3 with the composition x = 0.5 is a viable lead-free option for application in solid state refrigeration. [ABSTRACT FROM AUTHOR]

Lead-free dielectric capacitors have become a topic of great interest in response to the ever-increasing demand for high-performance and environmentally friend energy devices. As SrTiO 3 (STO) is paraelectrics, the extremely low spontaneous polarization limits the development of its energy storage applications. In this paper, the microstructure and ferroelectric properties of STO are adjusted by grain engineering to expand its application in energy storage. STO, SrTi 1-x Mn x O 3 (STM x , x = 0.01 and 0.04) and Sr 1-y La y TiMn 0.01 O 3 (SL y TM 0.01 , y = 0.01, 0.02, 0.03 and 0.04) thin films are synthesized by the sol-gel method and thoroughly investigated on the effects of A-site (La) and B-site (Mn) co-doping effects on the crystalline phase, morphology, dielectric, ferroelectric and energy storage characteristics of STO thin film. The results indicate that the SL 0.01 TM 0.01 thin film exhibits a breakdown electric field of 3666.2 kV/cm. The SL 0.02 M 0.01 thin film exhibits excellent frequency stability and low dielectric loss (<0.01) with an energy storage density of 29.5 J/cm3 and an efficiency of 83.7 % at 2600 kV/cm. Moreover, the sample shows good frequency stability (400–2800 Hz) and thermal stability (20−140 °C). These findings indicate the potential of (Mn, La) co-doped SrTiO 3 thin film for dielectric capacitor energy storage field applications. [ABSTRACT FROM AUTHOR]

In this paper, we describe the synthesis of cerium molybdate (Ce 2 (MoO 4) 3) and different compositions of Bi-doped cerium molybdate (Ce 2-x Bi x (MoO 4) 3) where x = 0.01, 0.03, 0.05, 0.07, and 0.09, through simple co-precipitation method. The synthesized materials were optically, structurally, and morphologically characterized by various sophisticated techniques, including UV–visible, FTIR, Raman, PXRD, BET, and SEM-EDX. Upon addition of bismuth, the optical band gaps are reduced from 3.35 eV (Ce 2 (MoO 4) 3) to 2.83 eV Ce 1.93 Bi 0.07 (MoO 4) 3. The charge storage potential and AC conductivity of the synthesized materials were investigated through dielectric studies where the dielectric constant increased by increasing dopant concentration up to 7 %. At 20 Hz, Ce 1.93 Bi 0.07 (MoO 4) 3 showed a significantly greater dielectric constant (3.597 × 106) compared to undoped Ce 2 (MoO 4) 3 (3.262 × 105). Similarly, the AC conductivity of Ce 1.93 Bi 0.07 (MoO 4) 3 increased up to 4.758 S m−1 compared to the undoped Ce 2 (MoO 4) 3 (2.270 S m−1) at 20 MHz. The photocatalytic efficiency was investigated against diclofenac potassium, which also considerably improved by increasing bismuth content. The maximum photodegradation efficiency of 87.9 % was observed for Ce 1.93 Bi 0.07 (MoO 4) 3 in 180 min under UV light irradiation at optimized conditions (pH = 4, catalyst dosage = 20 mg, and initial concentration of drug = 5 mg L−1). The photocatalytic reaction followed pseudo-first-order kinetics with a rate constant of 0.0108 min−1 with stability up to five successive runs of photocatalytic activity indicating its good recyclability. These findings suggest that Bi-doped cerium molybdate could be used as a promising material for photocatalysis and energy storage devices. [ABSTRACT FROM AUTHOR]

The conversion of renewable energy into chemical energy carriers, such as ammonia, enhances the accommodation of renewable energy for power distribution networks (PDN) and supports the decarbonization for ammonia production systems (APS). This paper addresses the integration of PDN with APS through a collaborative planning considering a carbon emission flow (CEF) model. A collaborative planning model with carbon emissions constraints is designed, and a sensitivity analysis is performed to evaluate the impact of varying renewable energy costs on the system. To further reduce carbon emissions from green ammonia production and stabilize renewable energy volatility, a nodal CEF model that incorporates energy storage systems (ESS), wind turbines (WT), and photovoltaics (PV) is proposed. The economic feasibility of the proposed model is verified via comprehensive experiments. Numerical results show that collaborative scheduling reduces both costs and carbon emissions in PDN and APS. Implementing a carbon tax encourages the transition from grey to blue ammonia production, while a decrease in renewable energy costs further promotes the shift from blue to green ammonia. Besides this, the analysis indicates that integrating long-term operation of WT and PV, together with low-cost renewable electricity and ESS, boosts the economic efficiency of the green ammonia production system. • An integration of PDN with APS through a collaborative planning considering CEF model is proposed. • Employing the CEF model to calculate carbon emissions from grey, blue, and green ammonia production. • Carbon tax is used as a tool to encourage the low carbon transition of ammonia production. • A CEF model that incorporates ESS, WT, and PV is designed and the economic feasibility of the proposed model is verified. [ABSTRACT FROM AUTHOR]

The structural, microstructural, dielectric, optical, ferroelectric, and magnetic properties of cobalt doped barium calcium titanate (BCT) (Ba 0.80 Ca 0.20 Ti 1-x Co x O 3 with x = 0.000, 0.005, 0.010, 0.015, and 0.020) ceramics have been reported in this paper. The ceramic samples were prepared by the conventional solid-state reaction method. For all of the prepared samples, the tetragonal structure with the space group P 4 mm has been confirmed using the refinement method through Rietveld refinement of X-ray diffraction patterns. Field Emission Scanning Electron Microscopy (FESEM) micrographs revealed that the average particle size exists in micrometre range (0.3–0.8) μm. Optical studies revealed a gradual decrease in the energy bandgap from 3.31 eV to 2.71 eV with increasing doping concentration. A decreasing trend was observed in the dielectric characteristics of the material with changing frequencies at room temperature. Ferroelectric (P-E loops) analysis displayed an increase in both remnant polarization and maximum polarization of the ceramic with the increasing applied electric field. The highest value for the energy storage efficiency (η) was calculated to be 20.51 %. Magnetic analysis conducted at room temperature revealed the enhancement in ferromagnetism with the increase in doping concentration. [ABSTRACT FROM AUTHOR]

Inverter-driven generation units (IDGUs) based on renewable energy sources (RES) are actively integrated into electric power systems (EPSs) as a part of carbon neutrality development vector. RES units based on solar energy (photovoltaic power plants (PvPPs)) connected to hydrogen-based electric energy storage system (EESS) have been being actively introduced recently. For connection of modern PvPPs and hydrogen-based EESS (HESS) to grid electric power converters (EPC) are used. Large-scale implementation of these devices causes changes of EPS dynamic properties due to properties of inverting EPCs and their automatic control systems. To study and analyze these properties mathematical modelling can be used. Software on calculation of electromechanical transients is usually used for modelling transient processes. In such software generic mathematical models are developed and used to calculate transients in EPSs with PvPPs and HESSs. These models have a number of features due to which the full range of processes accompanying implementation of PvPPs and HESSs into weak grids cannot be simulated. The paper proposes an alternative all-mode variant to model these units in EPS. [ABSTRACT FROM AUTHOR]

— This paper introduces a comprehensive modeling approach for optimizing the capacities of various energy converters and storage systems within a residential Energy Hub (EH). The model focuses on minimizing energy supply costs to customers while maximizing the utilization of renewable and hydrogen-based technologies. Through the optimization process, we determined that implementing CHP units in the EH could reduce total costs by approximately 78% with green tax incentives and by 46.7% without them. Additionally, the inclusion of an incentive to the EH resulted in a 27.2% reduction in total costs imposed on subscribers. The study also evaluates the impact of uncertainties in photovoltaic (PV) electricity generation, demonstrating the benefits of using stochastic optimization over deterministic methods. The results indicate that the economic advantage of this approach over deterministic methods is 86.75%–95.74% greater, depending on the scenario. Sensitivity analysis further reveals that the investment costs of fuel cells significantly influence the optimal capacity design and economic viability of the EH model. • Proposing a modeling procedure for hydrogen within renewable-based energy hub studies. • Extracting a probabilistic model for solar radiation and ambient temperature. • Presenting various operating strategies in planning studies of residential energy hubs. • Developing a stochastic optimization algorithm for running the proposed model. [ABSTRACT FROM AUTHOR]

Overcoming the use of conventional internal combustion engines for future transportation is mandatory to achieve sustainability. In this regard, hybrid electric vehicles comprising hydrogen fuel cells with Li-ion battery storage are gaining more attention. The paper proposes a robust approach for economic power-sharing between these sources. A predictive speed control strategy is realized to improve the vehicle's overall operation compared to conventional proportional–integral–derivative controller and tested for various standardized driving cycles. Additionally, a comprehensive techno-economic analysis using total cost of ownership is performed. Results suggest that hybrid vehicles with fuel cells and batteries are more economical with costs($) of 5. 81 e 04 , 2. 17 e 04 , and 2. 04 e 05 , for transient, modal, and manual driving cycles, respectively compared with internal combustion engines and batteries having 6. 23 e 04 , 3. 21 e 04 , and 2. 54 e 05. Furthermore, for evaluating the performance of the proposed predictive controller in terms of error minimization, various performance indices are obtained, compared, and tested using a hardware-in-loop platform. • Predictive control-based optimal power management approach. • Economic benefits through hydrogen fuel cells (HFCs) as an auxiliary energy source. • The controller's performance investigation through performance indices (PIs). • Validation using simulation and Hardware-in-loop results. • Techno-economic analysis for full lifetime use of the HEV. [ABSTRACT FROM AUTHOR]

This paper proposes a molecular model of covalent grafting of azobenzene derivatives with graphite-like carbon nitride based on hydrogen bond regulation to improve the azobenzene photothermal energy storage density. The enthalpy of isomerization (Δ H) of azobenzene molecular cis - trans isomers is calculated using density functional theory, and the magnitude of Δ H is used to evaluate the photothermal storage performance of the azobenzene graphite-like carbon nitride model. The results showed that the molecular Δ H value increased by 0.105–0.243 eV after the azobenzene derivatives were covalently grafted to the graphitic carbon nitride template. In addition, when the donator group replaced the active benzene ring ortho-site of azobenzene, its value was 0.069–0.295 eV higher than that of the electron-withdrawing groups. Moreover, intramolecular hydrogen bonds can stabilize cis - trans isomers and increase the energy of azobenzene. Compared with unsubstituted azobenzene, the energy of azobenzene Δ H containing one intramolecular hydrogen bond increased by 0.295 eV, while the energy of azobenzene Δ H containing multiple intramolecular hydrogen bonds increased by 0.775 eV. [Display omitted] • A molecular model for covalent grafting of azobenzene onto g-C 3 N 4 with hydrogen bond was developed. • The energy conversion density of azobenzene synthetic was determined using density functional theory. • The grafting effect was evaluated by considering intramolecular hydrogen bond, substitution location, and electron group. [ABSTRACT FROM AUTHOR]

[Display omitted] With the vigorous development and huge demand for portable wearable devices, wearable electronics based on functional fibers continue to emerge in a wide range of energy storage, motion monitoring, disease prevention, electromagnetic interference (EMI) shielding, etc. MXene, as an emerging two-dimensional inorganic compound, has shown great potential in functional fiber manufacturing and has attracted much research attention due to its own good mechanical properties, high electrical conductivity, excellent electrochemical properties and favorable processability. Herein, this paper reviews recent advances of MXene-based fibers. Speaking to MXene dispersions, the properties of MXene dispersions including dispersion stability, rheological properties and liquid crystalline properties are highlighted. The preparation techniques used to produce MXene-based fibers and application progress regarding MXene-based fibers into supercapacitors, sensors, EMI shielding and Joule heaters are summarized. Challenges and prospects surrounding the development of MXene-based fibers are proposed in future. This review aims to provide processing guidelines for MXene-based fiber manufacturing, thereby achieving more possibilities of MXene-based fibers in advanced applications with a view to injecting more vitality into the field of smart wearables. [ABSTRACT FROM AUTHOR]

Hydrogen is characterized by zero carbon emissions and high energy density, which can effectively support the consumption of a high proportion of intermittent new energy. Considering the seasonal nature of renewable energy sources, a seasonal hydrogen storage model is incorporated in an electric-hydrogen integrated energy system (EH-IES). In this paper, a two-layer optimization method is proposed for EH-IES with seasonal hydrogen storage. The problem of co-optimizing the equipment capacity and configuration in the proposed system is coordinated by establishing a two-layer optimization framework. Specifically, the system is optimized to minimize cost and carbon emissions at the upper layer using the multi-objective stochastic paint optimizer (MOSPO) algorithm, with the capacity configuration results being transmitted to the lower layer. The lower layer, aiming to reduce the total system cost, utilizes a commercial solver to obtain the optimal economic scheduling results for a typical day. The final analysis of the four scenarios shows that the increase in renewable energy reduces the purchasing cost of electricity by 1.89%, while in contrast, the total cost increases by 4.4% in the system with a lower proportion of renewable energy. In the case of higher heating and cooling loads, the increase in renewables reduces the purchase cost of natural gas by 9.10%. The results demonstrate that the proposed method can leverage the seasonal complementary benefits to drive new energy consumption, enhance system operation efficiency, and effectively reduce EH-IES's total operation cost and carbon emission. [Display omitted] • Seasonal hydrogen storage is introduced into the electric-hydrogen integrated energy system model. • A two-layer optimization model is developed in the electric-hydrogen integrated energy system. • A Multi-objective Stochastic Paint Optimizer (MOSPO) method is employed to solve the planning problem. [ABSTRACT FROM AUTHOR]

Hydrogen energy storage systems are becoming increasingly accepted owing to their environmental friendliness. The efficiency and performance of these systems largely depend on the attributes of their power electronic interface systems. Among the promising solutions is a multiport-isolated DC-DC converter with characteristics of reduced component count, fewer conversion stages, and galvanic isolation. However, this system presents a challenge due to its inherent cross-coupling effect, complicating precise control. To address this, linear active disturbance rejection control (LADRC) is a viable option, leveraging dynamic/disturbance properties observed by linear extended state observers. LADRC serves as a decoupling controller, mitigating the cross-coupling effect. However, LADRC has several gains, and selecting them can be a difficult task, often requiring manual tuning. To streamline this process, this paper proposes utilising particle swarm optimisation to determine the optimum gains of LADRC. By employing this approach, the implementation of LADRC is facilitated with reduced design efforts while ensuring effective decoupling control within the system. Simulations are conducted to validate the performance of the optimised gain LADRC. [ABSTRACT FROM AUTHOR]

The necessity of employing renewable energy sources within microgrid-based Power-to-X (P2X) systems has been emphasized by the imperatives of reducing global warming and fossil fuel consumption. Due to their numerous advantages, solar and wind energy have acquired prominence in contemporary power systems. However, their intermittent nature presents challenges. To overcome these challenges, energy storage devices are utilized. Batteries, however, are plagued by issues such as high maintenance needs, self-discharge, and diminishing storage capacity with age. Consequently, investigating alternatives such as hydrogen storage has become a financially viable option, especially for high-power applications. However, the intrinsically slow dynamics of hydrogen production from electricity contrast with the rapid responses of contemporary power electronic devices. This paper presents a versatile technique for optimizing hydrogen production in the presence of stochastic fluctuations in solar irradiance and wind speed. The proposed method combines a modified version of the Symbiotic Differential Whale Optimization Algorithm (m-SDWOA) with power converters to maximize production from renewable sources and electrolyzers. Using extensive simulations to demonstrate the efficacy of the proposed method by comparing its performance to that of the Whale Optimization Algorithm (WOA) and Particle Swarm Optimization (PSO). The results demonstrate the superior performance of the m-SDWOA-integrated method and pave the way for improved hydrogen generation in microgrid-based P2X systems. • Innovative control framework coordinates WT, PV, BESS, and HESS. • Maximizes hydrogen production while maintaining power quality. • Efficient controllers stabilize DC-bus voltage amidst WT/PV variability. • Ensures consistent, reliable power supply in microgrid. • Efficient energy management via m-SDWOA for resource optimization. [ABSTRACT FROM AUTHOR]

With the increasing demand for high energy density and reliable dielectric capacitors in the field of power electronics, the research and manufacture of ceramic capacitor materials face significant challenges. At present, the traditional design ideas of dielectric ceramic materials have gradually formalized, and the system is complex and similar, whether it can design dielectric ceramic materials with high performance from a new viewpoint and explore the underlying mechanism remains a great challenge. This paper is based on ceramic capacitors with high energy storage performance, a series of high-entropy perovskite oxide ceramics designed by the concept of "entropy engineering" in the past five years are reviewed. The relationship between microstructure and macroscopic energy storage performance of materials is discussed based on the four effects of high-entropy ceramics. We predict that "entropy engineering" will be a successful strategy to break through the bottleneck of dielectric materials with high energy storage performance. This review guides the custom design of composition-structure-properties in high-entropy energy storage ceramics. [ABSTRACT FROM AUTHOR]

The investigation of cost-effective and highly efficient electrocatalysts for alkaline water and simulative seawater oxidation is essential to the conversion and storage of renewable energy. In this paper, the Ce–NiSe 2 /CoP catalyst with multihole and ultrathin nanosheet structure is generated. The unique structural characteristics of Ce–NiSe 2 /CoP heterojunction nanosheets contribute the excellent OER performance under different alkaline 1 M KOH and simulated seawater (1 M KOH + 0.5 M NaCl) electrolytes. Specifically, this catalyst exhucture is generated. The unique structural characteristics of Ce–NiSe 2 /CoP heterojunction nanosheets conibits the low overpotentials of 287 and 304 mV at the current density of 10 mA cm−2, along with the Tafel slopes of 87.1 and 78.8 mV dec−1 in two solutions, respectively. Moreover, the Ce–NiSe 2 /CoP target product also displays good stability. The present study introduces a promising strategy for the advancement of high-performance electrocatalysts in green energy field. [Display omitted] • The Ce-doped NiSe 2 /CoP heterostructure nanosheets are triumphantly generated. • The Ce–NiSe 2 /CoP product possesses multihole and ultrathin lamella architecture. • Each nanosheet with coarse surface is composed of prolifically nanosecondary units. • This catalyst presents fine OER properties in alkaline water and simulative seawater. [ABSTRACT FROM AUTHOR]

Energy hubs (EHs) represent a pivotal paradigm in achieving optimal resource utilization across various energy domains. This paper presents an advanced framework for the optimal management of a smart island, leveraging the synergies within the water-electricity nexus. By integrating diverse resources, including electricity, water, heat, and hydrogen, the proposed EH model aims to meet the multifaceted demands of consumers on the island. To enhance operational efficiency, this study delves into the nuanced impacts of key EH components, elucidating their roles in meeting demand profiles and minimizing operational costs. Formulated as a mixed integer linear programming (MILP) model, the EH optimization problem is addressed using the GAMS optimization tool. The overarching objective is to fulfill consumer demand while concurrently optimizing resource utilization, considering factors such as storage degradation costs and emissions from fossil-fuel-based units. In addition to strategic optimization, this study pioneers a novel approach to stochastic parameter forecasting, integrating convolutional neural networks (CNNs) and long-short-term memory networks (LSTMs). By harnessing the capabilities of these advanced forecasting techniques, the EH model can anticipate dynamic changes in demand patterns with heightened accuracy and precision. The empirical results underscore the transformative potential of the proposed EH framework, showcasing significant reductions—up to 30%—in emission costs. Moreover, the study underscores the pivotal role of EHs as enablers for scaling up renewable energy penetration, offering a robust foundation for sustainable energy transitions in island communities and beyond. Additionally, implementing a load-shifting demand response program can lower total costs by approximately $257 per day, offering significant savings for EHs over extended periods. [Display omitted] • Modeling a mixed integer linear programming for energy management of an energy hub. • Comprehensive study on hydrogen and electric storage systems. • Uncertainty modeling using convolutional and long short-term memory networks. • Modeling water–electricity nexus to meet water and electricity demand. [ABSTRACT FROM AUTHOR]

High-entropy perovskite oxides (HEPOs) have attracted considerable attention as dielectric ceramics. However, the energy-storage performance of these HEPOs still requires improvement. In this study, a series of (1- x)(Bi 0. 4 Ba 0. 2 K 0. 2 Na 0.2)TiO 3 - x NaNbO 3 high-entropy ceramics were designed and prepared using a high-entropy strategy. The introduction of antiferroelectric NaNbO 3 into the (Bi 0. 4 Ba 0. 2 K 0. 2 Na 0.2)TiO 3 medium-entropy matrix increased the configurational entropy and cationic disorder, resulting in improved energy storage performance. The ceramic with an optimal composition of 0.775(Bi 0. 4 Ba 0. 2 K 0. 2 Na 0.2)TiO 3 -0.225NaNbO 3 achieved a high recoverable energy density (W rec) of 2.523 J/cm3 and a high efficiency (η) of 83.7% at an electric field of 220 kV/cm. Furthermore, the material demonstrated good temperature and frequency stability, as well as good anti-fatigue properties. This paper presents a dielectric ceramic suitable for energy storage under low to moderate electric fields. [ABSTRACT FROM AUTHOR]

The shared energy storage system is recognized as a promising business model for the coordinated operation of integrated energy systems (IES) to improve the utilization of energy storage and the consumption of renewable energy. As the hydrogen energy gradually receives more attention, this paper constructs the structure of a hybrid hydrogen energy storage system shared by an IES alliance in a dynamic pricing mode. A bi-level optimization model for the shared hybrid hydrogen energy storage system (SHHESS) is proposed to optimize the capacity configuration decisions and the pricing strategy jointly. The upper level determines the capacity and dynamic price of SHHESS with maximum profits and the lower level obtains the optimal operation of the IES alliance minimizing the total operation costs. The proposed model is solved by an improved PSO-GA algorithm and CPLEX solver. Finally, numerical tests are conducted in different scenarios. The results show that the hybrid energy storage system improves the daily profits of SHHESS by 70.3% and 5.44%, and reduces the renewable energy curtailment by 80.93% and 48.92% respectively compared to the battery-only and hydrogen-only systems. Additionally, the daily operation cost of the IES alliance is 35.2% lower than the individual operation scenario. The proposed model confirms the feasibility and superiority of the hybrid hydrogen energy storage system in a sharing business mode. • Design an interactive structure of a shared hybrid hydrogen energy storage system. • Propose a bi-level planning optimization framework for shared hybrid hydrogen energy storage. • The dynamic price of energy storage sharing service is optimized. • Determine the optimal operation strategy of the integrated energy system alliance. • Propose a hybrid method combining an improved PSO-GA and CPLEX optimizer. [ABSTRACT FROM AUTHOR]

This paper proposes a multi-objective framework for sustainable scheduling of hybrid hydrogen-power systems. In the proposed model, the microgrid system incorporated renewable energy systems, battery energy storage systems, non-renewable resources, power-to-hydrogen, hydrogen-to-power, demand response programs, and hydrogen storage systems to present a highly flexible structure in the energy systems. The purpose of the proposed model is to provide a complete operation mechanism for the daily scheduling of microgrids considering environmental, economic, and sustainable problems. To this end, a stochastic three-objective optimization model is proposed to consider the intermittent behavior of renewable generation, loads, and market prices and simultaneously tries to minimize the carbon emission, total cost, and peak loads. The peak load reduction is important because it increases the reliability, renewable energy integration, power quality, and reduced cost of reserve capacity. Therefore, a min-max approach is presented to reduce the peak load in the proposed model. Also, the hydrogen-to-power and power-to-hydrogen resources are integrated as flexible resources to increase the efficiency of microgrids during operation scheduling. The proposed model is evaluated on a standard case study and the numerical results show the multi-objective model reduces the carbon emission by 28.05 kg and increases the load factor by 6.26%, respectively. • Description of a multi-objective problem that integrates electricity and hydrogen. • Proposing an enviro-economic model to reduce carbon emission and operating cost. • The proposed model significantly uniforms the load profile by min-max approach. • Hydrogen storage tank and DR programs are considered to increase the flexibility. [ABSTRACT FROM AUTHOR]

In this paper, a diabatic compressed air energy storage system fueled by a natural gas/hydrogen mixture that integrates heating and power generation is proposed. A comprehensive thermodynamic analysis has been conducted to identify the key factors influencing system performance and elucidate the detailed formation and distribution patterns of irreversible losses when utilizing a hydrogen-natural gas blend as fuel in the proposed system. The research results indicate that increasing the hydrogen blending ratio from 0.5 to 1 lead to greater enhancements in roundtrip efficiency (∼1.08% vs. ∼0.33%), exergy efficiency (∼3.88% vs. ∼1.15%), and energy density (∼1.24% vs. ∼0.42%) compared to an increase from 0 to 0.5. The combustor suffers the largest exergy destruction proportion, with a notable reduction in exergy destruction achieved through increased hydrogen blending. System performance benefits significantly from higher combustor outlet temperatures and expansion ratios at various hydrogen blending ratios. The rate of change in exergy efficiency (∼42.76% vs. ∼83.17%) and energy density (∼58.83%) demonstrates an inverse correlation with the varied parameters (1100–1500K, 4–8), except for the rate of change in energy density (∼6.76%), which displays a positive relationship with the combustor outlet temperature. Notably, a significant decrease in the rate of change in roundtrip efficiency (∼1.87% vs. ∼6.64%) is observed within a specific parameter range (1400–1500K, 5–6). Sensitivity analysis identifies the combustor outlet temperature as the most influential factor in enhancing system performance, consistently showing positive effects of the hydrogen blending ratio. [Display omitted] • A natural gas/hydrogen-fueled CAES system combined heating and power is proposed. • Increasing the hydrogen contents significantly reduces combustor exergy destruction. • Higher hydrogen content (>0.5) yields notable performance boosts, especially in EXE. • The ROC s infected by ER display a remarkable correlation compared to the COT. • The COT is the crucial parameter on system performance via sensitivity analysis. [ABSTRACT FROM AUTHOR]

Oxidation of metals in water has been explored to generate sustainable carbon free hydrogen and power. This paper studies the thermal ignition of micro aluminum powders in high-pressure deionized (DI) water for cogeneration of hydrogen, heat, and alumina. Thermal ignition (temperature runaway) is necessary to ensure achieving high reaction temperatures, past the saturation temperature, where alumina formation is thermodynamically favorable. Aluminum powders with nominal particle diameters of 1, 10 and 45 μm with spherical morphology and 2 μm with flake morphology were mixed with DI water to form slurries with equivalence ratio of 1.3 in a 100 mL batch reactor. The reactor was pressure maintained between 500 and 2000 psig using a back-pressure regulator, and heat was injected into the slurry through an electric band heater. It was found that 1 and 2 μm powders ignite in compressed water, but only the 2 μm slurries achieved temperatures above saturation temperature at pressures above 700 psig. On the other hand, 10 and 45 μm powders require saturated steam for ignition at pressures above 1000 and 1200 psig, respectively. Hydrogen volume data indicate that larger powders at higher pressures optimize reaction yield, which is likely due to delayed ignition which preserves the active aluminum content and the particle-water reaction interfaces. Scanning electron microscopy images illustrate that the byproduct particles crack upon ignition at the saturation temperature, which increases the specific surface area by an order of magnitude relative to the aluminum powders. Pore size distribution data indicates the formation of micro, meso and macropores upon the ignition. X-ray powder diffraction data indicate that reaction temperatures above 450 °C promote the formation of alumina (Al 2 O 3) instead of boehmite (ALOOH). • Hydrogen, heat and alumina are cogenerated from reaction of aluminum with water. • Pressure controls the onset of reaction. • Specific surface area of the powder has a significant impact on ignition. • Presence of steam is necessary for ignition of larger powders. • High specific surface area alumina powder is produced. [ABSTRACT FROM AUTHOR]

Modern energy systems are large distributed systems and, as a rule, contain energy storage systems and, in particular, hydrogen batteries and hydrogen production systems. The use of hydrogen for energy transportation has recently been actively studied in a number of scientific projects. To ensure continuous operation of instrumentation and control equipment on long hydrogen pipelines (gas and cryogenic), it is important to ensure constant autonomous power supply to these systems. This can be solved using micromechanical energy microgeneration systems for the uninterrupted operation of various sensors, which are installed in large numbers on almost all elements of the structure and infrastructure. In addition, an important area of scientific research is the revision of the concepts and appearance of traditional devices of modern renewable energy: windmills, solar cells, turbines, etc. Fundamentally new energy devices are on the agenda, capable of recovering mechanical energy of any power and supplying it to the consumer in the form of a given specific energy flow. Collection of chaotically distributed natural energy of the environment (mechanical energy in the form of: vibrations, acoustic vibrations, wave energy, gusts of wind, tornadoes, precipitation, vibrations of the earth's crust, etc.), as well as collection of dissipated energy from artificial sources (iron and automobile highways, airstrips, spaceports, production facilities, etc.) with the help of mechanical microgenerators will allow the recovery and conversion of mechanical energy of various powers, including low power, into a universal energy carrier - hydrogen. Mechanical vibrations of artificial origin are of particular interest due to their widespread use for domestic and industrial purposes in a wide range of vibrations. The energy of mechanical vibrations can be collected and converted into electrical energy using piezoelectric, electromagnetic, triboelectric or electrostatic (capacitive) energy converters. Electrostatic microelectromechanical energy converters are considered the most promising among other energy converters, since their manufacturing processes are based on standard technology for the production of integrated circuits and microelectromechanical systems. Energy conversion by an electrostatic converter is carried out due to an external mechanical force that does work against the force of attraction of the charged electrodes of a variable capacitor. To transfer the received electrical energy to the load of the consuming device, the electrostatic converter is connected to the corresponding electrical circuits (conditioning circuits). Such a system as a whole is a kind of microgenerator or energy collector. Microenergy flow recovery systems integrated into large energy systems will ensure the collection and recovery of significant amounts of energy for remote energy consumers. At the same time, the concept of a distributed mechanical energy recovery system is quite simple: a mechanical energy receiver - a converter into electrical energy - a preliminary electrical storage device - an energy distributor - an electric energy accumulator - an electrolyser - a hydrogen accumulator - a fuel cell. To optimize the operation of the working circuit, including preliminary electrical systems for energy storage and conversion: capacitors and electric energy accumulators, electrolyzers; To ensure their durability and reliability, flexible automatic control of electrical power distribution is necessary. The real work was done to solve that problem. In addition, for extended and large power facilities it is important to ensure widespread sensory control of system parameters. At the same time, if all sensors receive power from an autonomous energy-generating device, then the costs of creating extended communications for instrumentation will be sharply reduced. In addition, the reliability of the control system will significantly increase. The results of studying operation features of a kinetic microgenerator with reduced output voltage are presented. The performance of a multi-stage modified Bennet doubler is compared to a system including a two-stage modified Bennet doubler and a diode-capacitor voltage divider. It is shown that with an increase of the number of stages in the modified Bennet doubler, the conversion of mechanical energy into electrical energy becomes less and less efficient. At the same time, for achieving the maximum energy accumulation rate (power), a two-stage power amplifier based on the Bennet doubler is preferable. It is established that when analyzing the operation of a diode-capacitor voltage divider, it is necessary to take into account the intrinsic (reverse) capacitances of the discharging diodes affecting the divider operation significantly. The divider behavior features while changing the load resistance and the intrinsic capacitances of the discharge diodes are found and analyzed. Analytical expressions linking the main characteristics of the microgenerator as a whole with the parameters of the electronic components used are derived. It is shown that for expanding the range of the "correct" division of the divider, it is necessary to use discharge diodes with minimal intrinsic capacitances, and also that connecting a load to the Bennet doubler as a voltage divider changes the permissible capacitance modulation depth of the variable capacitor. This paper examines the concepts of creating large energy-generating flows based on arrays of micromechanical energy converters placed on optimal energy-efficient receiving surfaces and analyzes the issues of cryogenic production, storage, consumption and transportation of hydrogen. Stationary and mobile cryogenic storage systems for hydrogen are considered. Much attention is paid to the safety of large cryogenic and gas hydrogen systems. [ABSTRACT FROM AUTHOR]

Renewable energy production through electrolysis of water to obtain "green hydrogen" has gained interest as a clean energy storage option. However, integrating variable renewable energy resources into the grid poses challenges to maintaining energy balance and stability. In this paper, a hybrid energy storage system combining short-term battery energy storage system and long-term hydrogen-based energy storage system is proposed for an isolated DC microgrid with a structure similar to a hydrogen refueling station. Passivity-Based Control (IDA-PBC) is utilized for power converters regulation, ensuring global stability based on Lyapunov theory while accounting for the nonlinear characteristics of the physical system. The control strategy is designed to ensure a reliable supply of electrical energy to the loads, preserve the quality of electrical variables in the network, and secure the safe operation of system components. Additionally, to safeguard devices from overvoltage, a Sliding Mode Reference Conditioning loop (SMRC) is proposed. It intervenes only when there is a potential risk of exceeding predefined boundaries. Simulations results under demanding conditions demonstrate the effectiveness of incorporating hydrogen energy storage systems with IDA-PBC and SMRC for this class of problems. • An isolated MG with H2 storage, typical structure of a refueling station, was modeled. • The IDA-PBC ensures the stability of the nonlinear and complex MG. • SMRC ensures overvoltage protection in the bus. • The control confirms that H2 storage integrated with RES contributes to MG stability. [ABSTRACT FROM AUTHOR]

This paper presents the synthesis of multifunctional ceramics, represented as Sr 2- x Sm x Ag 0.2 Na 0.8 Nb 5- x Ti x O 15 , through the solid-state reaction method. Smaller ions in both A and B sites were co-substituted, resulting in a notable relaxation behavior, which was analyzed to determine the contributing factors for underlying structural mechanisms. Introducing Sm3+ and Ti4+ not only transformed the structure from Im 2 a to Bbm 2 symmetry and then eventually to paraelectric P 4/ mbm phase, but also induced the evolution of incommensurate structure and the formation of nano-domains to modulate relaxation behavior. Notably, the enhanced energy storage properties (W rec ∼ 3.38 J/cm3, η ∼ 84.5 %) and desirable red-orange emission performance (λ em = 610 nm) were obtained for Sr 1.7 Sm 0.3 Ag 0.2 Na 0.8 Nb 4.7 Ti 0.3 O 15 ceramics. Moreover, the multifunctional ceramics exhibited high power and current densities (P D ∼ 116.38 MW/cm3, C D ∼ 1026.43 A/cm2) together with a prolonged decay life (745 μs). Therefore, the proposed materials may be suitable for potential applications in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Hydrogen energy storage systems (HESS) play an essential role in Microgrid (MG) systems to address the inherent generation characteristics of renewable energy sources. Also, the integration of Demand Response (DR) into the Energy Management System (EMS) of a renewable-based Multi-Microgrid (MMG) can lead to substantial technical and economic benefits. This paper proposes a modified optimization algorithm for optimizing MMG Energy Management (EM). The proposed algorithm is a modified version of the Student Psychology-Based Optimization (SPBO) technique called Modified Student Psychology-Based Optimization (MSPBO). This modification aims to improve issues such as slow convergence, low solution accuracy, lack of diversity, and getting stuck in local optima. The proposed MSPBO method incorporates a local escape operator and a collaborative student class to achieve a better balance between exploiting known solutions and exploring new possibilities. The MSPBO algorithm is applied to address the EM challenge within a MMG context. Considering the integration of renewable sources as Wind turbines and solar photovoltaic and the HESS, the EM problem is formulated as a two-stage multi-objective optimization: minimizing the operating cost of conventional generators and power transactions cost in addition to the cost of HESS, while maximizing operator benefits and peak load reduction. This multi-objective problem is tackled using a hybrid ε-lexicography–weighted-sum approach that avoids the need for normalization. The performance of the proposed MSPBO is evaluated using CEC 2017 benchmark test functions, utilizing various statistical measures such as best, average, worst, rank, and standard deviation (SD) of fitness values, along with Wilcoxon's rank-sum test. The MSPBO technique is compared with other optimization algorithms for these test functions, highlighting its efficiency and adeptness in achieving a harmonious trade-off between exploiting known solutions and exploring new ones. Furthermore, the MSPBO method is applied to solve two case studies. In Case 1, which involves a single stage with conventional demand response optimization, the results achieved using MSPBO are benchmarked against other optimization techniques, revealing its superior efficacy in addressing the EM challenge. In Case 2, a more complex two-stage multi-objective problem is tackled using MSPBO, and the assessment of the integration of HESS in the MMG is evaluated. In the second stage, there is a notable enhancement in peak load reduction percentage (PRP), from 13.9% to 16.13% without the HESS and from 12.68% to 16.46% with the integration of HESS. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carriers (LOHC) can be used as a lossless form of hydrogen storage at ambient conditions. The storage cycle consists of the exothermic hydrogenation of a hydrogen-lean molecule at the start of the transport, usually the hydrogen production site, becoming a hydrogen-rich molecule. This loaded molecule can be transported long distances or be used as long-term storage due to its ability to not lose hydrogen over long periods of time. At the site or time of required hydrogen production, the hydrogen can be released through an endothermic dehydrogenation reaction. LOHCs show similar properties to crude oils, such as petroleum and diesel, allowing easy handling and possibilities of integration with current infrastructure. Using this background, this paper reviews a variety of aspects of the LOHC life cycle, with a focus on currently studied materials. Important factors such as the hydrogenation and dehydrogenation requirements for each material are analysed to determine their ability to be used in current scenarios. Toluene and dibenzyltoluene are attractive options with promising storage attributes, however their dehydrogenation enthalpies remain a problem. The economic feasibility of LOHCs being used as a delivery device were briefly analysed. LOHCs have been shown to be the cheapest option for long distance transport (>200 km), and are cheaper than most at shorter distances in terms of specifically transport costs. The major capital cost of an LOHC delivery chain remains the initial investment for the raw materials and the cost of equipment for performing hydrogenation and dehydrogenation. Finally, some studies in developing the LOHC field were discussed, such as microwave enhancing parts of the process and mixing LOHCs to acquire more advantageous properties. • Efficient hydrogen storage solution for sustainable energy transportation and storage. • Enables safe and cost-effective hydrogen transportation and distribution networks. • Promotes renewable energy integration through versatile and scalable storage capabilities. • Facilitates decarbonization efforts by enabling long-term, stable hydrogen supply chains. [ABSTRACT FROM AUTHOR]

Due to the outstanding thermal properties of nanoparticles, scientists have introduced a range of multidisciplinary applications in fields such as heat transfer systems, thermal management, solar energy, chemical processes, manufacturing, and cooling technologies. The aim of the current paper is to inspect the heat and mass transfer pattern during Maxwell nanofluid flow considering the diffusion phenomenon. The suspension of microorganisms has been considered for bioconvective flow. The inspection of heat transfer is analyzed by adopting the nonlinear radiated effects. The motivations for considering the Maxwell fluid are associated to novel relaxation time features occurring in polymer industry and manufacturing systems. The endorsed flow is caused by periodically oscillating surface with porous medium. The whole mathematical model is developed in terms of partial differential equations (PDE's). A successful analytical solution is presented via homotopy analysis method (HAM). It is observed that solutal concentration reduces due to modified Duffer Lewis number and Deborah number. The surface heating parameter and magneto-porosity constant enhances the temperature profile. The predicted results convey significant impact in enhancing the energy reservoirs, diffusion applications, nuclear systems, oil industry, storage energy, space exploration etc. [ABSTRACT FROM AUTHOR]

Distribution feeder reconfiguration (DFR) in distribution systems can enhance operating conditions by reducing losses and improving voltage indices. This paper introduces a dual-stage risk-based framework that concurrently tackles day-ahead reconfiguration and microgrid scheduling within the distribution network. To control the negative aspects of uncertainties, the proposed framework integrates energy storage systems (ESS/HSS) and demand response programs (DRPs) at the network level, enhancing adaptability. The initial stage of the proposed model employs the AC power flow model, utilizing loss and voltage deviation functions as objective benchmarks for network reconfiguration. The scheduling is meticulously executed per interval, deriving optimized structures under diverse scenarios with the aid of a case reduction technique (CRT) to streamline solutions. The ultimate solution employs the grey wolf optimization (GWO) algorithm and CPLEX solver in the first and second stages respectively. Outcomes from applying this approach to the adjusted 118-bus network manifest improved operational conditions and voltage quality through reconfiguration. Impressively, the integration of ESS/HSS and DRPs yields a substantial 22.34% reduction in total operating costs, a conclusion substantiated by the numerical findings. Furthermore, by leveraging the CRT, a remarkable 56.17% reduction in problem-solution time is achieved. [Display omitted] • Investigating the impact of losses and voltage deviations on network performance. • Introducing a two-stage risk-based framework to determine the optimal topology. • Finding solutions to the micro-grids planning problem with the distribution network reconfiguration. • Adopting a case reduction method to lessen time demand required for solving the day-ahead planning problem. • Investigating the effect of demand response programs on the voltage characteristics and losses of the system. [ABSTRACT FROM AUTHOR]

• A novel system is proposed to utilize LNG cold energy in cascade. • Thermodynamic and economic analyses are carried out for the proposed system. • The system is compared to other systems in the same field for performance evaluation. • The round-trip efficiency of the proposed energy storage system is 138.81 %. For cutting down the energy consumption and improving the cold energy conversion efficiency of the traditional liquefied air energy storage system (LAES), a novel energy system integration solution is proposed by combining the LAES with liquefied natural gas (LNG) regasification process. In this paper, the principal energy storage and energy release processes are simulated by Aspen Hysys. The influences of air mass flow rate and LNG regasification pressure on the performance are analyzed. The results indicate that the introducted system can attain 137.82 % round-trip efficiency, which is about 20 % higher than the conventional LAES system. Besides, the energy capacity reaches up to 10.87 MW and the exergy efficiency is 39.58 % during long-distance transportation. It's noteworthy that the power output in the liquefied air energy discharging period far exceeds the power generation from the organic Rankine cycle. The higher LNG transport pressure, the worse LNG-LAES system performance. When the air mass flow rate raises from 40,000 kg/h to 64,000 kg/h, the exergy efficiency is 3.4 % higher than the original, while the round-trip efficiency decreases by 29.79 %. Finally, through economic viability calculations, the dynamic recovery period of the LNG-LAES system is 5.41 years. [ABSTRACT FROM AUTHOR]

High entropy materials are becoming more and more popular in energy storage field of supercapacitors because of their unique structure and modulated functional characteristics, but their low conductivity and instability of electrode structure limit their further electrochemical performance. In this paper, we use polyethylene glycol (PEG) with different molecular weights to modify the surface morphology of the high entropy oxides (FeCoCrMnNi) 3 O 4 in an attempt to improve their supercapacitors performance. The PEG was used as a pore-making agent to prepare porous high entropy oxides powder with a large specific surface area of 92.7559 m2 g−1, providing more active sites and ion transport channels. A high specific capacitance of 204 F g−1 at 0.5 A g−1 and good cycle performance of 60.4 % capacitance retention after 10,000 cycles were obtained. Besides, an asymmetric device with improved energy density of 53 W h kg−1 and the power density of 400.8 W kg−1 were reached via the designed microstructure of the high entropy oxide electrode. [ABSTRACT FROM AUTHOR]

In this paper, certain issues envisaged in the framework of development of design methodology for intelligent autonomous distributed hybrid power complexes (ADHPC) with green hydrogen and energy storage, functioning in grid mode and in the mode of interaction with the global (national) grid (GN) have been solved. Depending on their energy deficit or surplus, relative to the global grid, ADHPCs can operate as a load or as an energy source, respectively, as follows: based on the analysis of the energy balance management process in the ADHPC, a reasonable choice of the structure of the system of accumulation and distribution of power flows (SADCF) was made from the point of view of increasing the reliability of its functioning and ensuring the physical feasibility of the energy balance management process in this structure, i.e. keeping the actual power consumption of the consumers close to the required rated power at each given time t. This is achieved by including a condenser connected to the SADCF system on its assembly and distribution bus and a storage system BS with double-level ((BS1, BS2), double-circuit ((BS1(1), BS1(2)), (BS2(1), BS2(2))) structure, whereby: BS1of the level 1 - to manage the capacity balance in the SADCF under normal ADHPC regime and the variation of green hydrogen and consumption capacities within their confidence intervals assessed at the design stage; BS2 of the level 2 - to coordinate ADHPC and GN modes of operation and to control, together with BS1 of the level 1, GN, diesel generator (DG), the power balance in the SADCF when the ADHPC fails and when RES and consumption power are outside their confidence intervals; alternating charge/discharge operation of the parallel circuits will extend the life of the BS system; – a comprehensive definition of optimal ADHPC system situational energy balance management task is formulated. [ABSTRACT FROM AUTHOR]