High Energy Research Articles

Electron-Efficient Co-electrosynthesis of Formates from CO2 and Methanol Feedstocks.

The electrochemical conversion of CO2 into valuable chemicals using renewable electricity shows significant promise for achieving carbon neutrality and providing alternative energy storage solutions. However, its practical application still faces significant challenges, including high energy consumption, poor selectivity, and limited stability. Here, we propose a hybrid acid/alkali electrolyzer that couples the acidic CO2 reduction reaction (CO2RR) at the cathode with alkaline methanol oxidation reaction (MOR) at the anode. This dual electro-synthesis cell is implemented by developing Bi nanosheets as cathode catalysts and oxide-decorated Cu2Se nanoflowers as anode catalysts, enabling high-efficiency electron utilization for formate production with over 180% coulombic efficiency and more than 90% selectivity for both CO2RR and MOR conversion. The hybrid acid/alkali CO2RR-MOR cell also demonstrates long-term stability exceeding 100 hours of continuous operation, delivers a formate partial current density of 130 mA cm-2 at a voltage of only 2.1 V, and significantly reduces electricity consumption compared to the traditional CO2 electrolysis system. This study illuminates an innovative electron-efficiency and energy-saving techniques for CO2 electrolysis, as well as the development of highly efficient electrocatalysts.

Thermo-economic optimization on a combined heat and power system with supercritical Rankine cycle for power-to-heat batteries

The global energy structure is transforming to low-carbon, and it is urgent to construct a sustainable energy system mainly based on renewables. The power-to-heat batteries (P2HBs) show great potential for large-scale energy storage by converting low-cost renewable power to heat. This paper aims to study the thermodynamic and economic advantages of the P2HB integrated with a supercritical steam Rankine cycle (RC) to achieve combined heat and power (CHP) generation. Firstly, a system model of P2HB-CHP consuming grid valley power is developed. The system includes three sub-systems: P2HB, steam generator, and CHP. Thermodynamic and economic analysis models are developed, and the average exergy efficiency (ηav) and net present value (NPV) are formulated as performance evaluation targets, respectively. The genetic algorithm is used to perform multi-parameter optimization of the system. The thermodynamic optimization results show that the maximum ηav of supercritical P2HB-CHP is 0.47 %, 1.16 %, and 1.44 % higher than that of subcritical P2HB-CHP when the high working temperature of the molten salt reaches 505 °C, 570 °C, and 640 °C, respectively. The largest proportion of anergy is generated by electric heaters, over 72 %. The next largest proportion is heat exchangers, which is related to the heat transfer temperature differences. The results of the economic analysis show that the maximum NPV of supercritical P2HB-CHP is lower by 158 M$, lower by 74 M$, and higher by 55 M$ than that of subcritical P2HB-CHP when the high working temperature of the molten salt is reached 505 °C, 570 °C, and 640 °C, respectively. The high efficiency of supercritical RC reduces the costs of electric heaters and molten salts, but sets high demands on the heat exchangers. Although high-temperature molten salt results in high energy efficiency, the increased cost of molten salt reduces the profitability of the system.

Time-of-flight vs time-of-arrival in neutron spectroscopic measurements for high energy density plasmas.

The neutron time-of-flight (nToF) diagnostic technique has a lengthy history in Inertial Confinement Fusion (ICF) and High Energy Density (HED) Science experiments. Its initial utility resulted from the simple relationship between the full width half maximum of the fusion peak signal in a distant detector and the burn averaged conditions of an ideal plasma producing the flux [Lehner and Pohl, Z. Phys. 207, 83-104 (1967)]. More recent precision measurements [Gatu-Johnson etal., Phys. Rev. E 94(8), 021202 (2016)] and theoretical studies [Munro, Nucl. Fusion 56, 035001 (2016)] have shown the spectrum to be more subtle and complicated, driving the desire for an absolute calibration of the spectrum to disambiguate plasma dynamics from the conditions producing thermonuclear reactions. In experiments where the neutron production history is not well measured, but the neutron signal is preceded by a concomitant flux of photons, the spectrum can be in situ calibrated using a set of collinear detectors to obtain a true "time-of-flight" measurement. This article presents the motivation and overview of this technique along with estimates of the experimental precision needed to make useful measurements in existing and future nToF systems such as the pulsed power Z-machine located in Albuquerque, NM, at Sandia National Laboratories.

Mechanical Design, Construction and Testing of the Superferric Dipoles for the High Energy Fragment Separator of the HIAF

Mechanical Design, Construction and Testing of the Superferric Dipoles for the High Energy Fragment Separator of the HIAF

De-emulsifying barriers to the circular economy-a fertilizer industry perspective

PurposeThe fertilizer industry (FI) is well known for its high energy needs, reliance on limited natural resources, and negative environmental impacts (EIs). The consumption of 14.2 billion tons (BT) of materials and the extraction of 1,580 tons of resources per acre are solely attributed to the FI. Because of FI's resource and energy-intensive nature, it becomes crucial for FI to adopt a Circular Economy (CE) to improve efficiency, energy, and resource reuse. However, FI needs to strengthen its progress toward CE adoption. The proposed study comprehends and examines the barriers that inhibit the adoption of CE in FI.Design/methodology/approachA total of 15 barriers obstructing the CE in FI are identified and categorized into seven different categories. The barriers were identified by performing a comprehensive literature review and expert input. The study employs the DEMATEL approach to analyze the barriers and establish a causal relationship between them.FindingsThe study reveals that the most significant challenge to implementing CE in FI is governmental restrictions, which are followed by a lack of awareness and understanding and a need for a steady supply of bulk materials. The results comprehensively comprehend the pivotal factors that jeopardize the CE in FI and furnish a robust foundation for the methodology and tactics to surmount the barriers to CE adoption.Originality/valueThe literature review encompasses the barriers to the transition to CE and offers management and policy perspectives that help the FI's policy and decision-makers surmount these barriers with future research endeavors.

Tuning the composition of manganese cobaltite spinel with tungsten for enhanced energy storage performance

The development of efficient and innovative energy storage devices is a necessity of the hour. Emerging nanomaterials possessing tungsten are believed to have unique physicochemical properties and their application could be extended over a wide spectrum as nanocomposite electrodes for effective high voltage energy storage applications. In the present work, a one-step hydrothermal process has been employed to prepare Tungsten (W) doped spinel oxide MnWxCo2–2xO4 (MWCO) nanostructures, where x varies from 0.01 to 0.05. The spectroscopic characterization studies proved spherical subunits embedded onto nanosheets formed by W doped bimetallic oxide with a crystalline phase. On employing the synthesized material in asymmetric supercapacitor application, it was inferred that W doping had a notable effect on the electrochemical performance. The optimized doping ratio (x=0.03) revealed an appreciable specific capacitance of 91 F g−1 at the current of 0.5 A g−1, with a retention in the capacitance of more than 80 % even after 10000 GCD cycles. Remarkable specific energy (3.17 Wh kg−1) and specific power (98 W kg−1) were also noted. Hence, the material synthesized in this study by our facile method is thought to be highly suitable as an electrode for high-performance energy storage applications.

Effects of intercritical annealing time on microstructure, tensile properties, and cryogenic toughness of newly designed ultra-low C low Ni Medium-Mn steel

An ultra-low carbon and low nickel medium manganese heavy steel plates was fabricated by quenching and intercritical annealing process. The effect of annealing time on the tensile properties and impact toughness were studied in relation to the formation of reversed transformation. The results show that excellent mechanical properties with yield strength of 680 MPa, tensile strength of 871 MPa, total elongation of 38.2% and high impact energy of 187 J at −60 °C were obtained. The microstructure comprised of ultra-fine grained ferrite and retained austenite (RA) together with a small amount of martensite after intercritical annealing. Increasing the intercritical annealing time resulted in coarser matrix microstructures, larger and more voluminous retained austenite, but with notably reduced stability. Highly stable RA enhances the work hardening capacity of the steel via sustained deformation-induced transformation (TRIP effect), significantly contributing to the toughening of the multiphase system. In addition, Austenite stability, rather than large-angle grain boundaries and the amount of austenite transformation, is the primary factor determining the low-temperature toughness of medium manganese steel.

Eigenfrequency analysis using fiber optic sensors and low-cost accelerometers for structural damage detection

Structural Health Monitoring (SHM) is crucial for infrastructure safety and integrity. Arduino-based sensors are gaining popularity in low-cost SHM structures. Distributed fiber optic systems (DFOS), such as Distributed Acoustic Sensing (DAS), are employed for accurate SHM despite their high costs, computational demands, and energy consumption. The primary objectives of this work are to compare the accuracy of an accelerometer named LARA (Low-cost Adaptable Reliable Accelerometer (LARA)) that utilizes both Arduino and Raspberry Pi technologies with a DAS system in detecting structural damage and to explore the potential advantages of combining LARA and DAS to create an effective SHM tool. This study is the first to enhance the design of LARA. Subsequently, LARA and DAS were used in a laboratory setting to analyze eigenfrequency changes in a beam model with induced localized damage. Finally, this study evaluated the precision and reliability of LARA and its potential role as a trigger for DAS in detecting localized damage. The findings show that both LARA and DAS can identify changes in the eigenfrequencies of damaged structures with deviations as small as 3.68 %. Consequently, LARA demonstrated its potential as a trigger for DAS, significantly reducing the computational demands while enriching the analysis. This approach offers highly accurate eigenfrequency measurements and enhances the analytical capabilities of DAS by identifying the primary axes of the detected eigenfrequencies.

Digital Implementation of Chaotic Systems UsingNvidia Jetson AGX Orin and Custom DAC Converter

Digital implementation of chaotic systems has numerous advantages, offering higher flexibility and computational accuracy compared to traditional analog systems. This is particularly important for engineering applications. Digital solutions are also more cost-effective. In this study, the Nvidia Jetson AGX Orin board and a 16-bit converter board are used for the digital realization of chaotic systems. The Nvidia Jetson AGX Orin provides high processing power and energy efficiency, while the 16-bit converter card ensures precise data processing. This setup allows for advanced, flexible, reliable, and economical solutions, enhancing various engineering applications, such as modeling, simulation, and control of complex systems. Digital platforms also facilitate parametric investigations and optimization processes, enabling more in-depth analysis.

Unlocking the ultrafast laser response and low initiation energy of perchlorate-free tetrazine-based energetic coordination compounds

Laser ignition technology holds significant and diverse applications in the domains of weapon equipment, aerospace and engineering blasting because of its exceptional resistance to electromagnetic interference, outstanding ignition efficiency and flexible controllability. However, the commercial initiation material B/KNO3 still suffers the high minimum laser initiation energy (Emin = 723.2 mJ) and lengthy ignition delay time (ID=160 ms). In this study, we have successfully synthesized two perchlorate-free energetic coordination compounds (ECCs): [Cu(DHT)(NO3)(H2O)](NO3) 1 and [Ni(DHT)(H2O)2](NO3)22 (DHT=3,6-dihydrazine-1,2,4,5-tetrazine). Though two compounds with similar structures show high explosion parameter values, the behaviors of laser responsive ignition are different. Noteworthy, laser ignition tests demonstrate that Cu-based 1 exhibits excellent laser response characteristics with an ultra-low Emin value of 4.2 mJ and a short ID time of 20 ms, while Ni-based 2 shows extremely insensitivity to laser under identical conditions. Furthermore, theoretical calculations reveal that the higher sensitivity of 1 towards laser response activity might be attributed to the narrower band gap (Eg = 0.44 eV) resulting from Cu centers in contrast with 2. In addition, mechanical sensitivities between 1 and 2 are discussed sufficiently by theoretical and structural studies. Compared to the commercial B/KNO3, compound 1 has promise to serve as a competitive laser ignition material.

From low-cost mineral to high-performance Li4SiO4 for solar energy storage and CO2 capture

The huge consumption of fossil fuels results in excessive CO2 emissions and its reduction has become a common concern. The combination of renewable energies (i.e., solar energy) and carbon capture, utilization, and sequestration are well recognized as two major routes to achieving carbon neutrality. Lithium orthosilicate (Li4SiO4) has been identified as one of the most promising candidates for solar energy storage and CO2 capture. However, the cost reduction and performance enhancement remain to be the main obstacles for its practical application. In this work, high-performance Li4SiO4 heat carriers have been synthesized using low-cost mineral as silicon source for solar energy storage and CO2 capture. Li4SiO4 derived from diatomite exhibited cyclic energy storage densities above 500 kJ/kg. The performance was further improved by doping alkali carbonates, particularly doping 3 wt% K2CO3 (LD-P-3K), which exhibited high and stable energy storage density of approximately 700 kJ/kg in the tested 10 cycles. Then, the mechanism of alkali doping was revealed through experiments and DFT calculations. The DSC results demonstrated that the improved performance was attributed to the formation of a eutectic melt which reduced the CO2 diffusion resistance. The DFT calculations showed that K-doped Li4SiO4 had lower adsorption energy and more significant charge migration, which meant stronger interaction. Additionally, diatomite-derived Li4SiO4 material is also a promising candidate for high-temperature CO2 capture, evidenced by its relatively high cyclic CO2 capture capacity (∼0.25 g/g). In general, satisfactory density/capacity and stability endows diatomite-derived Li4SiO4 with great prospects for both thermochemical energy storage and high-temperature CO2 capture.

In situ three-dimensional reconstruction and gradient-induced design of ultrastable Zn metal anodes in Zn-Se batteries

Zinc-selenium batteries have high specific and volumetric capacities, but practical development faces key challenge in achieving stable zinc metal anodes, and avoiding zinc dendrite growth, hydrogen evolution reaction (HER) and corrosion. Here, a zinc foam substrate is employed to fabricate three-dimensional gradient electrodes Zn foam@Cu@CuSe2 (ZFCCS) with gradient change of zincophilicity and conductivity. Experimental observations and simulations collectively confirm that the three-dimensional structure and gradient design effectively homogenize interfacial ion flux and diminish local current density. This optimization of the zinc deposition path synergistically fosters high flux and deep deposition of zinc metal while simultaneously preventing dendrite growth. The results demonstrate that the developed ZFCCS electrode produces an excellent Coulombic efficiency of 99.5 % over 1000 plating/stripping cycles, and the corresponding symmetric cell provides an ultra-long dendrite-free cycle life of 800 h at 5 mA cm−2 and 2 mAh cm−2 with a low overpotential of 27.4 mV. In addition, the Zn-Se full cell based on the designed ZFCCS composite anode exerts superior stable cycle life (358.1 mAh g−1 at 2 A g−1 after 1000 cycles). Therefore, the gradient design strategy based on 3D electrodes will be a reference for high performance energy storage devices.

Flexible High‐Temperature Polymer Dielectrics Induced by Ultraviolet Radiation for High Efficient Energy Storage

AbstractPolymer‐based dielectrics with fast electrostatic energy storage and release, are crucial for advanced electronics and power systems. However, the deterioration of insulation performance and charge–discharge efficiency of polymer dielectrics at elevated temperatures and high electric fields hinder the applications of capacitors in harsh environments. Herein, a facile and scalable approach is reported to fabricating flexible high‐temperature polymer dielectrics for high‐efficiency energy storage by ultraviolet irradiation. The resultant dielectric films exhibit an augment of 493% in energy density and exceeding 800% in discharge efficiency at 200 °C (3.2 J cm−3 and over 90% discharge efficiency at 480 M V−1m for irradiated polyetherimide (PEI), 0.54 J cm−3, and below 10% discharge efficiency at 400 MV m−1 for pristine PEI) and excellent cycle performance. The injected space charge is found to be the dominant contributor to energy loss during the charge–discharge process. Free radicals introduced by ultraviolet irradiation can act as deep traps to capture injected charge and suppress space charge migration. This work clarifies the contribution of space charge to energy loss and demonstrates the effectiveness of ultraviolet irradiation in improving the capacitive performance of high‐temperature polymer dielectrics. These findings provide a novel paradigm for the rational design of high‐temperature polymer dielectrics for high‐efficiency energy storage.

Advanced MXene materials: Paving the way for next-generation lithium-sulfur batteries in energy storage

In recent years, lithium-sulfur (Li-S) batteries, with high theoretical energy density and low cost, have become one of the most promising energy storage systems. However, the insulation of sulfur, the "shuttle effect" of polysulfides and volume expansion hinder their practical applications. MXenes have excellent electrical conductivity, high specific surface area, and a strong adsorption capacity for polysulfides, which helps to overcome the shortcomings of traditional Li-S batteries. In this paper, the structure, properties and preparation methods of MXenes are reviewed, and the applications of MXenes in the cathode, separator and anode of Li-S batteries are introduced. Finally, the future directions of MXenes in the field of Li-S batteries are prospected.

Recyclable NaCl template assisted preparation of N/O co-doped porous carbon for zinc-ion hybrid capacitor

The traditional strong alkaline activation method for preparing porous carbon faces with complex preparation processes, equipment corrosion, excessive disordered microporous structures, and environmental pollution. Hence, a green, facile and sustainable method is proposed for synthesizing N/O co-doped porous carbon derived from polyacrylamide gel with the assistance of recyclable sodium chloride (NaCl) template. NaCl template is dissolved in gel with water and can give full play to the template effect after recrystallization. Due to a suitable specific surface area (499.8 m2 g−1) and massive N (11.38 at. %) and O (8.71 at. %) functional groups, the optimized NPC-5 electrode possesses a high specific capacitance of 283.3 F g−1 at 0.5 A g−1, superior rate characteristics and excellent cycle stability in 6 M KOH aqueous electrolyte. In addition, the constructed NPC-5//NPC-5 symmetric supercapacitor shows a high energy density of 34.0 Wh kg−1 in 1 M ZnSO4 aqueous electrolyte. More importantly, the assembled Zn//ZnSO4//NPC-5 hybrid capacitor shows a high capacity of 115.44 mAh g−1 and an energy density of 85.3 Wh kg−1.

An inspection of the metal-foam beam considering torsional dynamic responses

Metal foam is a multifunctional material with a lower specific weight, high stiffness and compressive strength, and high energy absorption. These remarkable properties make metal foams a promising candidate for conventional materials in different industrial fields. Despite numerous researches on mechanical behavior either static or dynamic of structures made of metal foams, torsional vibration analysis of metal foam structures is still uninvestigated. In this investigation, the influence of various imperfection distribution patterns on the torsional dynamic response of metal foam beams is examined within the framework of Timoshenko-Gere's theory. Two common materials i.e. SUS304 and Aluminum foams are considered the constructive materials of structure. Moreover, three imperfection distribution patterns are taken into account. The virtual work's principle has been employed to derive the torsional governing equation of metal foam beams. Then, the derived governing equation has been solved via an analytical method. The accuracy of the employed methodology has been compared with the findings of former research in the literature. Finally, the influences of different notable parameters on the variation of natural torsional frequency have been examined and demonstrated in a group of tables and diagrams.

Customizable 3D-printed decoupled structural lithium-ion batteries with stable cyclability and mechanical robustness

Structural batteries are considered one of the promising strategies for improving the endurance of electric vehicles. However, the trade-off between load-bearing capability and electrochemical performance remains a significant challenge. This paper proposes an efficient 3D printing-assisted fabrication strategy for high-performance structural batteries with customizable geometric configurations. The composite structural battery sample shows a bending modulus of 24.5 GPa, which could withstand maximum tensile stress and three-point bending stress of 155 MPa (specific tensile strength of 88340 N m kg−1) and 123 MPa (specific bending strength of 61553 N m kg−1). Meanwhile, it can achieve a high energy density of 120 Wh kg−1 and 210 Wh L−1 (3.5 mA cm−2) and superior capacity retention of up to 92 % after 500 cycles (10.5 mA cm−2). More importantly, the in-situ mechanical-electrochemical test demonstrates exceptional performance, retaining an ultra-high capacity of 98.7 % under a tensile stress of 80 MPa, and maintaining a capacity retention rate of 97 % with an average capacity decay per cycle of only 0.18 % under a bending stress of 96.3 MPa. In addition, finite element analysis is also used to verify the failure mechanism of the battery under bending load. Meanwhile, the fabricated structural battery can be applied to autonomous mobile robots, showing the multifunction energy storage and load-bearing. As a result, this work showcases the great potential of incorporating high-performance structural batteries into engineering applications such as small-scale warehousing, logistics equipment, and intelligent robotics.

Maximizing Waste-to-Energy Potential: Optimizing Batch Torrefaction Reactor of Refused-Derived Fuel for Efficient Gasification

Abstract Refuse-derived fuel (RDF) from municipal solid waste (MSW) is a promising alternative to fossil fuels, but its varied composition can impede direct gasification. This industrial research project conducted a series of batch experiments to assess four key parameters: energy yield, mass yield, energy density, and combustion characteristics in the context of RDF torrefaction. The batch reactor processed RDF samples at temperatures of 250°C, 300°C, and 350°C, each with a 30- minute residence time under an inert atmosphere. In addition, Combustion TGA experiments, involving heating torrefied RDF up to 1000°C at a rate of 20°C/min, provided further insights into the robust combustion properties of the torrefied material. Unlocking the secrets of torrefaction magic, we've achieved remarkable energy content boosts. Torrefaction at 250°C, 300°C, and 350°C led to energy content enhancements of 22%, 29%, and 37%, respectively, compared to the original RDF. Notably, the most favorable energy yield was achieved during torrefaction at 250°C, attributed to both its relatively high energy content and mass yield. At a torrefaction temperature of 250 °C and above, the torrefied RDF samples exhibited heating values comparable to standard coal ranges between 25-35 MJ/kg. It is suggested that torrefaction of RDF is an effective pre-treatment process to be used in entrained flow gasifier due to the improved higher heating value, higher energy density, and superior combustion characteristics, proved by the ignition index, flammability index, and burnout index, highlight the effectiveness of the torrefaction process.

Energy-efficient synthetic antiferromagnetic skyrmion-based artificial neuronal device.

Magnetic skyrmions offer unique characteristics such as nanoscale size, particle-like behavior, topological stability, and low depinning current density. These properties make them promising candidates for next-generation spintronics-based memory and neuromorphic computing. However, one of their distinctive features is their tendency to deviate from the direction of the applied driving force that may lead to the skyrmion annihilation at the edge of nanotrack during skyrmion motion, known as the skyrmion Hall effect (SkHE). To overcome this problem, synthetic antiferromagnetic (SAF) skyrmions that having bilayer coupling effect allows them to follow a straight path by nullifying SkHE making them alternative for ferromagnetic (FM) counterpart. This study proposes an integrate-and-fire (IF) artificial neuron model based on SAF skyrmions with asymmetric wedge-shaped nanotrack having self-sustainability of skyrmion numbers at the device window. The model leverages inter-skyrmion repulsion to replicate the IF mechanism of biological neuron. The device threshold, determined by the maximum number of pinned skyrmions at the device window, can be adjusted by tuning the current density applied to the nanotrack. Neuronal spikes occur when initial skyrmion reaches the detection unit after surpassing the device window by the accumulation of repulsive force that result in reduction of the device's contriving current results to design of high energy efficient for neuromorphic computing. Furthermore, work implements a BNN accelerator using proposed IF neuron and SAF-SOT MRAM-based synaptic devices for MNIST image classification.The presentedapproach achieves significantly higher energy efficiency compared to existing technologies like SRAM and STT-MRAM, with improvements of 2.31x and 1.36x, respectively. The presented accelerator achieves 1.42x and 1.07x higher throughput efficiency per Watt as compared to conventional SRAM and STT-MRAM based designs.&#xD.

Binaphthyl Mediated Low Temperature Synthesis of Carbon Nitride Photocatalyst for Photocatalytic Hydrogen Evolution.

Metal-free graphitic carbon nitrides are on the rise as polymer photocatalysts under visible light illumination, taking shares in a range of promising photocatalytic reactions, including water splitting. Their simple synthesis and facile structural modification afford them exceptional tunability, enabling the creation of photocatalysts with distinct properties. While their metal-free nature marks a significant step towards environmental sustainability, the high energy consumption required to produce carbon nitride photocatalysts remains a substantial barrier to their widespread adoption. Furthermore, the process of condensation at approximately 550 °C typically results in solid yields of less than 15 %, significantly challenging their economic viability. Here, we report on lowering manufacturing conditions of carbon nitride photocatalysts whilst enhancing photocatalytic activity by introducing binaphthyl diamine as a structural mediator. At 450 °C in 2 hours, carbon nitride photocatalyst shows a lower bandgap and enables visible light induced hydrogen evolution (194 μmol h-1) comparable to benchmark carbon nitride photocatalysts.