Conversion Devices Research Articles

Light-Powered Directional Ion Transport via PFN-Br/MoS2 Heterogeneous Membranes: Band Alignment and Activation Energy Barrier Engineering.

Biological photoresponsive ion transport systems consistently attract researchers' attention owing to their remarkable functions of harvesting energy from nature and participating in visual perception systems. Designing and constructing artificial light-driven ion transport devices to mimic biological counterparts remains a challenge owing to fabrication limitations in nanoconfined spaces. Herein, a typical conjugated polyelectrolyte (PFN-Br) was assembled onto a laminated MoS2M using simple solution-processing vacuum filtration, resulting in a heterogeneous three- and two-dimensional nanoporous membrane. The designed band alignment between PFN-Br and MoS2 enables effective directional ion transport under irradiation in an equilibrium solution, even against a 30-fold concentration gradient. The staggered energy structure of PFN-Br and MoS2 enhances charge separation and establishes a photogenerated potential as the driving force for ion transport. Additionally, the activation energy barrier for ion transport across the heterogeneous membrane decreased by 60% after light irradiation, considerably improving ion transport flux. The easy fabrication and high performance of the membrane in light-powered ion transport provide promising approaches for designing nanofluidic devices with possible applications in energy conversion, light-enhanced biosensing, and photoresponsive ionic devices.

Energy storage mechanism and modeling method of underground aquifer to meet the demand of large-capacity new energy consumption

With the increasing scale of new energy, the ability to rationally utilize new energy power abandonment has become key to improving the operational efficiency of new power systems in the future. Existing new energy power abandonment consumption methods have problems such as limited consumption capacity and large-scale applications. Therefore, to consume the large-scale power abandonment of new energy and enable it to be stored for a long time, this study proposed a method in which electro-thermal conversion devices are used to convert electric energy into thermal energy, and the energy is stored in an underground aquifer. A finite element numerical analysis model was constructed to analyze and calculate this process. A multi-physical field coupling numerical analysis model, considering the seepage of groundwater and the heat transfer of the heat exchangers and porous media, was constructed by combining the distribution characteristics of power abandonment and a theoretical analysis of the heat transfer principle of an aquifer. A scaled test platform was constructed based on the similarity principle to verify the accuracy of the numerical analysis model. The results of the numerical analysis and simulated test showed that the energy storage system could store power abandonment in the form of thermal energy in the aquifer. At the same time, the annual energy loss of the system is only 14.89%, indicating that the system has long-term storage capabilities. In addition, a comparative analysis of the consumption effects of energy storage systems of different sizes showed that an aquifer energy storage system can be configured according to the capacity of power abandonment. Thus, a large-capacity new energy consumption space can be constructed to realize the complete consumption of power abandonment.

Machine learning assisted understanding of the layer-thickness dependent thermal conductivity in fluorinated graphene

Manipulating thermal conductivity (κ) plays vital role in high-performance thermoelectric conversion, thermal insulation and thermal management devices. In this work, we using the machine learning-based interatomic potential and the phonon Boltzmann transport equation to systematically investigate layer thickness dependent κ of fluorinated graphene (FG). We show that the lattice κ of FG can be significantly decreased with Bernal bilayer stacking. Surprisingly, the further increasing of stacking layer can no longer affect the κ, however, the κ is increased in the bulk configuration. The variation of κ can be attributed to the crystal symmetry change from P-3m1 (164) at single layer to P3m1 (156) at multilayer. The decreasing crystal symmetry from single layer to bilayer resulting stronger phonon scattering and thus leading a lower κ. Moreover, we also show that the contribution of acoustic mode to κ decreases with the increase of layers, while the contribution of optical mode to κ is increased with increasing layers. These results provide a further understanding for the phonon scattering mechanism of layer thickness dependent κ.

Graphene-supported MN4 single-atom catalysts for multifunctional electrocatalysis enabled by axial Fe tetramer coordination

Multifunctional electrocatalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) are crucial for development of the key electrochemical energy storage and conversion devices, for which single-atom catalyst (SAC) has present great promises. Very recently, some experimental works showed that structurally well-defined ultra-small transition-metal clusters (such as Fe and Co tetramers, denoted as Fe4 and Co4, respectively), can efficiently modulate the catalytic behavior of SACs by axial coordination. Herein, taking the graphene-supported MN4 SACs as representatives, we theoretically explored the feasibility of realizing multifunctional SACs for ORR, OER and HER by this novel axial coordination engineering. Through extensive first-principles calculations, from 23 candidates, IrN4 decorated with Fe4 (IrN4/Fe4) is identified as the promising trifunctional catalyst with the theoretical overpotential of 0.43, 0.51 and 0.30 V for OER, ORR and HER, respectively. RhN4/Fe4 and CoN4/Fe4 are recognized as potential OER and ORR bifunctional catalysts. In addition, NiN4/Fe4 exhibits the best ORR activity with an overpotential of 0.30 V, far superior to the pristine NiN4 SAC (0.88 V). Electronic structure analyses reveal that the significantly enhanced ORR/OER activity can be ascribed to the orbital and charge redistribution of Ni/Ir active center, resulting from its electronic interaction with Fe4 cluster. This work could stimulate and guide the rational design of graphene-based multifunctional SACs realized by axial coordination of small TM clusters, and provide insights into the modulation mechanism.

Salt‐Based Catalyzer to Aid Heterogeneous Nucleation Enabling >23% Efficient Electron‐Transport‐Layer‐Free Perovskite Solar Cells

AbstractCharge transport layers are critical components in perovskite solar cells (PSCs) for achieving satisfied power conversion efficiencies (PCEs) and device stability. However, these layers often bring incompatible interfaces and complex fabrication, limiting the stability and scalability of PSC technology. Here an alternative strategy of salt‐based catalyzer (SBC) is proposed to regulate the heterogeneous nucleation of perovskite, which enables uniform and well‐controlled perovskite coverage directly onto the salt‐treated substrate without electron transport layers (ETLs). By carefully adjusting the cations, anions, and the thickness of SBC, high‐quality perovskite films along with superior buried interfaces suppress the carrier recombination losses and strengthen the interfacial stability, promoting the resultant device to achieve a record PCE of 23.04%, which represents the highest reported efficiency for ETL‐free PSCs. Meanwhile, the SBC technique can be well extended to large‐area, flexible, and module‐based devices. More encouragingly, the SBC‐based unencapsulated devices exhibit remarkable operational stability by retaining over 90% of initial efficiency for 1540 h under illumination and for 6312 h in an air environment. This work provides an advisable way to fabricate efficient and stable ETL‐free PSCs toward reliable and cost‐effective production.

Tunable Near-Field Radiative Heat Transfer between Graphene-Coated Magneto-Optical Metasurfaces.

The highly structured design of metasurfaces greatly facilitates the manipulation of near-field radiative heat transfer (NFRHT). In this study, we incorporate magneto-optical materials into metasurfaces to theoretically explore the mechanism for controlling NFRHT between anisotropic magneto-optical metasurfaces. Our findings indicate that the interaction between the magnetization-induced modes, arising from interband transitions of graphene, and the surface modes of InSb under a magnetic field leads to a transition in the heat transfer spectrum from a dual band to a triple band. The modification of the distribution and magnitude of transmission wave vectors in surface electromagnetic modes by magnetic fields serves to modulate the radiative heat flux. By combining active control by a magnetic field with passive structural design of metasurfaces, the regulation of heat flux can be increased by more than 8-fold compared with the planar configuration. Additionally, the magnetic field amplifies the anisotropy of the photon energy distribution induced by the symmetry breaking of the metasurface structure. This study is anticipated to provide a pathway for achieving flexible tuning of NFRHT by combining active and passive regulation. It also opens up possibilities for multiband information transmission and for improving the performance of energy conversion devices.

One single-atom Mn doping strategy enabling two functions of oxygen reduction reaction and pseudocapacitive performance

Single-atom metal species as highly effective active sites are crucial for enhancing energy storage and conversion properties. However, achieving the simultaneous construction of single-atom sites and the regulation of matrix structures to enable their application in both energy storage and conversion remains a challenge. Here, we have successfully developed unique MnN2C2 active sites, atomically dispersed on N-doped mesoporous graphitic carbon sheets (MnSAs/NMC). This is accomplished through the strategic utilization of MnCl2 salt, which serves dual roles of a pore-forming agent and a template. The MnSAs/NMC catalyst demonstrates compelling electrocatalytic activity for the oxygen reduction reaction (ORR), with an impressive half-wave potential (E1/2 = 0.90 V), alongside superior capacitance reaching 444 F g-1 at 0.5 A g-1 for supercapacitors. Crucially, both experimental and theoretical simulations validate that the single-atom dispersed MnN2C2 optimizes the adsorption energy of reactants and intermediates in the ORR process and pseudocapacitive behavior, leading to excellent ORR activity and capacitive performance. Interestingly, MnSAs/NMC-based Zn-air batteries exhibit concurrently high-power density derived from capacitive property and high energy density enhanced by ORR process. This study presents a novel preparation method for single-atom catalysts, which paves the way for the commercial application of super energy storage and conversion devices.

Enhancing PEC hydrogen generation efficiency: Robust ZnO-GaN hierarchical nanowires loaded with NiS for superior charge separation and transportation

We present a method for the sequential fabrication of a three-dimensional hierarchical structure, comprising ZnO nanowires (NWs) grown atop Vapor-Liquid-Solid (VLS) GaN NWs using Metal Organic Chemical Vapor Deposition (MOCVD) for applications in photoelectrochemical water splitting (PEC-WS). To enhance the PEC performance and photostability of the system, we performed NiS anchoring. The optimized 60 NiS/ZnO-GaN hierarchical nanowires (HNWs) exhibited a remarkable 23-fold enhancement (1.62 %) in photoconversion efficiency at 0.75 V vs reversible hydrogen electrode (RHE) compared to GaN NWs passivated with ZnO deposited by atomic layer deposition (ALD) (0.07 %), alongside an 18.9-fold increase in photocurrent density (7.6 mAcm−2 @ 1.23 V vs RHE). Additionally, these hierarchical structures demonstrated exceptional photostability over a period of 10 hours (36000 s) at 0.8 V vs RHE. The hierarchical assembly is crucial in achieving high photoconversion efficiency and photostability. The rational design of hierarchical NW photoanodes synergistically enhances both photocurrent and photostability, paving the way for facile integration of II-VI with III-V materials and potentially unlocking advancements in next-generation energy harvesting and conversion devices.

Electrical conductivity of polyvinyl alcohol/carboxymethyl cellulose doped by zinc oxide and hematite nanoparticles for optoelectronics devices

This research explores polymer nanodielectrics, a category of materials where nanoceramic fillers are incorporated into polymers. These hybrid materials are gaining significant interest because of their tunable optical and electrical characterization, making them potentially well-suited for applications in flexible optoelectronic and organic electronic devices. Polyvinyl alcohol (PVA), Carboxymethyl cellulose (CMC), zinc oxide (ZnO), and hematite (Fe2O3) nanoparticles were utilized to fabricate PVA/CMC-ZnO/Fe2O3 films XRD analysis indicated a reduction in the crystalline character of the PVA/CMC blend following the doping of ZnO/Fe2O3 nanoparticles (NPs). FTIR data approved the complexation between the PVA/CMC blend and the ZnO/Fe2O3, leading to a decrease in intermolecular interactions within the polymeric matrix and coordination with the ZnO/Fe2O3. Electrical analysis obtained an enhancement in σac values with the increase of ZnO/Fe2O3 NPs concentration up to 30 min of laser ablation times The findings from this study suggest the promise of these materials for applications in high-performance batteries, supercapacitors, or other next-generation energy storage and conversion devices.

Sequential Deposition of Diluted Aqueous SnO2 Dispersion for Perovskite Solar Cells

The widespread use of tin dioxide (SnO2) thin films as electron transport layer (ETL) of perovskite solar cells (PSCs) has been facilitated by commercial SnO2 nanocolloid dispersion. Nevertheless, challenges such as nanoparticle agglomeration have emerged, impacting film quality and interface properties critical for PSC performance. Herein, the efficacy of sequential, multistep spin‐coating of repeatedly diluted SnO2 aqueous suspension as a simple and effective approach to enhance ETL properties is explored. Through systematic experiments using dynamic light scattering, cyclic voltammetry, optical spectroscopy, and photoconductivity, it is demonstrated that the sequential deposition significantly improves the flatness and coverage of SnO2, leading to improved electron transport and transfer from a perovskite layer. Such a synergetic effect enables to fabricate lead iodide PSC (FAPbI3, FA: formamidinium) with a power conversion efficiency of 22.99% compared to 20.48% for the conventional 1‐step SnO2 layer. The findings underscore the potential of sequential SnO2 deposition as a promising technique for robust SnO2 films of photoelectric conversion devices.

Modulation of morphology and electronic structure of cobalt thiophenedicarboxylic coordination polymer via ligand exchange for high-performance oxygen evolution reaction and supercapacitor

Rationally designing metal organic frameworks (MOFs) as an ideal dual-function material for water electrolysis and supercapacitors is of great significance for energy storage and conversion. Herein, we successfully synthesized the nanoneedle-like structure CoNi-MOF by partially replacing 2, 5-thiophenedicarboxylic acid (TDA) with 1, 1′-Ferrocenedicarboxylate (Fc). The exchange of Fc ligand can modulate the morphology and electronic structure of CoNi-TDA, thus exposing the abundant active sites and improving the electrical conductivity. The as-prepared CoNi-TDA/0.2Fc exhibited a low overpotential of 236 mV at 10 mA cm−2 for oxygen evolution reaction (OER) and a low Tafel slope of 40.44 mV dec−1. Additionally, CoNi-TDA/0.2Fc demonstrated a notable specific capacitance of 1409 F g−1 at 1 A/g and excellent stability, maintaining a capacitance retention of 96.54 % after 20,000 cycles. The study proposes a new strategy to modulate the morphology and electronic structure of MOFs via the ligand exchange for high-performance energy storage and conversion device.

Manipulating the Crystallization of Tin Halide Perovskites for Efficient Moisture-to-Electricity Conversion.

Manipulating the crystallization of perovskite in thin films is essential for the fabrication of any thin-film-based devices. Fabricating tin-based perovskite films from solution poses difficulties because tin tends to crystallize faster than the commonly used lead perovskite. To achieve optimal device performance in solar cells, the preferred method involves depositing tin perovskite under inert conditions using dimethyl sulfoxide (DMSO), which effectively retards the formation of the tin-bromine network, which is crucial for perovskite assembly. We found that under ambient conditions, a DMSO-based tin perovskite salt solution resulted in the formation of a two-phase system, SnBr4(DMSO)2 and MABr, whereas a dimethylformamide-based solution resulted in the formation of vacancy-ordered double perovskite MA2SnBr6. Humidity is known to solvate MABr to form the solvated ions, and so we used the two-phase system for the application in moisture to electricity conversion. The importance of the presence of the scaffold can be seen with the negligible power output from the vacancy-ordered double perovskite obtained with MA2SnBr6. We have fabricated a device with two-phase system that can generate an open-circuit potential of 520 mV and a short-circuit current density of 30.625 μA/cm2 at 85% RH. Also, the device charges a 10 μF capacitor from 150 mV at 51% RH to 500 mV at 85% RH in 6 s at a rate of 52.5 mV/s. Moreover, the output can be scaled by connecting devices in series and parallel configurations. A 527 nm green LED was powered by connecting five devices in series at 75% RH. This indicates a potential for utilizing these moisture-to-electricity conversion devices in powering low-energy requirement devices.

FeMnO3/CNT as a synergistic bifunctional electrocatalyst for oxygen reduction and oxygen evolution reactions in alkaline medium

The development of highly effective and low-cost electrocatalysts for energy conversion and storage devices is triggered by the sluggish kinetics of oxygen reduction and evolution reactions. Perovskite-based oxides are identified as potential ORR and OER electrocatalysts in an alkaline medium. Thus, the present study discusses the synthesis and characterization of FeMnO3/CNT as a bifunctional catalyst with a low potential gap of 0.89 V. The FeMnO3/CNT composite was synthesized by the solution combustion method and characterized using spectroscopic and electron microscopic techniques. The increase in the ID/IG ratio obtained from the Raman spectra of the FeMnO3/CNT composite with respect to bare CNT indicates the functionalization of CNT. The ORR and OER characteristics of the FeMnO3/CNT composite were analyzed with rotating ring disc electrode and rotating disc electrode measurements. The LSV curve of the FeMnO3/CNT composite synthesized with 0.3g of CNT show better ORR and OER activity. The ORR activity measurements of the composite done in 0.1 M KOH electrolyte show a good onset potential of 0.95 V vs. RHE and a half-wave potential of 0.74 V. The HPRR studies show that the ORR reaction mechanism follows a 2e− + 2e− reduction pathway. The OER measurements in an alkaline medium show an onset potential of 1.63 V vs. RHE with a Tafel slope of 115.3 mV dec−1. Also, this work gives an insight into the fundamental understanding of the synergy between the perovskite and CNT, leading to an enhanced ORR and OER catalytic activity. In addition, the material exhibits good stability for ORR and OER stability studies.

Exploring electroacoustic conversion in a standing-wave thermo-acoustic generator: An experimental study

Thermoacoustic generators (TAGs) present an attractive solution for converting low-grade thermal energy into useable electrical power. Despite their relatively modest fabrication, TAGs face significant efficiency challenges that impede their broader adoption. Current research efforts in thermoacoustics are primarily focused on overcoming these limitations. A critical factor influencing TAG efficiency is the design of the acoustic-to-electric (ATE) device. This component plays a vital role in converting the acoustic energy generated within the thermoacoustic engine (TAE) into electricity. Despite its importance, the impact of ATE design on overall TAG performance has often been overlooked in previous studies. This research aims to address this gap by investigating how different ATE configurations influence the efficiency of power conversion within thermoacoustic systems. Specifically, this study delves into the potential of electromagnetic devices: linear alternators and loudspeakers, as ATE converters in a Standing Wave Thermoacoustic Generator (SWTAG) framework using air at atmospheric conditions. Firstly, a comparative analysis was conducted between two types of linear alternators—moving magnet and moving coil and tested with different magnet types (rare earth and ferrie anisotropic) to evaluate their impact on voltage generation. Secondly, the influence of various factors on energy conversion using loudspeakers was investigated, including loudspeaker type (paper cone vs. polypropylene cone), housing geometry (diameter and length), housing material (galvanized steel vs. PVC), open versus closed ATE housing design and utilizing dual loudspeakers. The generated electricity was utilized to power a light bulb. Linear alternators resultsMoving coil configuration outperformed the moving magnet design due to its lighter weight. Rare earth disc magnets generated higher voltage outputs compared to ferrie anisotropic magnets. The moving coil configuration achieved a maximum voltage output of 454 mV, while the moving magnet design reached a maximum of 312 mV. Both linear alternator configurations displayed low overall efficiencies. This is likely due to a mismatch between the magnet and coil diameters, leading to inefficiencies in capturing the generated magnetic field. Loudspeakers resultsPaper cone loudspeakers demonstrated superior performance due to their greater displacement capability. The Saknyo-Paper cone loudspeaker configuration achieved a voltage output of 4.11 V. Optimal voltage generation was achieved when the loudspeaker diameter matched the ATE device housing diameter. Galvanized steel housing offered better performance than PVC housing due to reduced vibration losses. The voltage outputs for the galvanized steel and PVC configurations were 4.11 V and 2.21 V, respectively. Closing the loudspeaker housing resulted in decreased voltage output due to wave interference. The voltage outputs for the galvanized steel and PVC configurations were 3.33 V and 1.62 V, respectively. Dual loudspeakers significantly enhanced voltage generation compared to a single loudspeaker. The maximum voltage recorded for the dual loudspeaker configuration was 6.5 V.The developed thermoacoustic generator achieved an output voltage exceeding the target of 6 V and thermal-to-electric efficiency of 3.42 % with an output electric power of 10.56 W, surpassing previous air-powered TAGs operating at atmospheric conditions. The generator successfully illuminated a light bulb, demonstrating its ability to generate useable electricity. This study provides valuable insights into optimizing the design of acoustic-to-electric conversion devices in TAGs. The findings highlight the importance of factors such as material selection, housing geometry, and magnet type for maximizing energy conversion efficiency.

Effect of AZO seed layers on the ultraviolet photoresponse of Ag/ZnO NRs Schottky junctions

Al-doped ZnO (AZO) thin films with different layers were prepared by sol-gel method. The SEM, XRD and AFM for three layers thin films demonstrates high crystal quality and low roughness. ZnO nanorods arrays (NRs) with different AZO seed layers were fabricated using hydrothermal process, and the effect of AZO seed layers on the structural, optical, and electrical characteristics was investigated. When there are three AZO seed layers present, ZnO NRs exhibit fewer surface states, smaller interface charge transfer resistance (Rce = 6.1 × 103Ωand Rct = 6.6 × 106Ω), longer carrier lifetimes (τe = 4.0 ms), higher carrier concentration (ND = 4.73 × 1019 cm−3), and narrower depletion region width W = 3.1 nm. Under weak UV light 381 nm (5.68 mW/cm2) at a bias −0.5 V, Ag/ZnO NRs Schottky devices with three AZO seed layers display a comparatively strong responsivity 34.64 mA/W. Appropriate AZO seed layers are favorable for highly efficient ZnO NRs-based photoelectric conversion devices.

Constructing high-performance micro fuel electrodes for reversible proton ceramic electrochemical cells

Reversible proton ceramic electrochemical cells (R-PCECs) are of great interest as efficient energy conversion device. Optimization of structural design can enhance the mechanical properties and gas transport of the cells, resulting in improved electrochemical performance. In this study, we developed a 7-channel micro-monolithic R-PCEC for the first time, with uniform channel distribution and smaller gas diffusion pathway length using phase inversion/extrusion technique. The assembled cell with Ni-BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (Ni-BZCYYb, fuel electrode support) | BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb, electrolyte) | PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF, air electrode) structure showed a peak power density of 0.94 W cm−2 at 700 °C in fuel cell mode and electrolysis current density of 2.17 A cm−2 at 700 °C with an operating voltage of 1.3 V. Additionally, electrochemical impedance spectroscopy (EIS) further indicated that the diffusive polarization of the structured cell was effectively reduced compared to single-channel counterpart.

Test and analysis of energy characteristics of large vertical submersible pumps

The efficiency of the pump device is an important parameter to judge the overall dynamic performance of the pumping station. The commonly used method at home and abroad is to carry out model tests of the pump device. The performance parameters of the prototype pump and pump device are obtained by the similarity conversion formula. However, at present, there are not many device model tests for large vertical submersible pumps. Taking a large vertical submersible mixed-flow pumping station in China as an example, research predicted the performance of the pump device through a model test and a submersible pump prototype test. The results show that the model test of the large vertical submersible mixed-flow pump device has a maximum efficiency of approximately 77.8%, and the prototype test conversion device has a maximum efficiency of approximately 80.33%. The device model test and the pump factory prototype test results are compared. It is found that the performance parameters of the pump measured by the prototype test are in good agreement with the device model test under the design conditions, and there is a certain error when the deviation from the design conditions is significant. The device model test and the factory test of the pump are indispensable in the large-scale road of submersible pumps, and a large number of tests are needed to sum up the experience.

Size Dependence of Ultrafast Electron Transfer from Didodecyl Dimethylammonium Bromide-Modified CsPbBr3 Nanocrystals to Electron Acceptors.

Charge transfer efficiencies in all-inorganic lead halide perovskite nanocrystals (NCs) are crucial for applications in photovoltaics and photocatalysis. Herein, CsPbBr3 NCs with different sizes are synthesized by varying the ligand contents of didodecyl dimethylammonium bromide at room temperature. Adding benzoquinone (BQ) molecules leads to a decrease in the PL intensities and PL decay times in NCs. The electron transfer (ET) efficiency (ηET) increases with NC size in complexes of CsPbBr3 NCs and BQ molecules (NC-BQ complexes), when the same concentration of BQ is maintained, as investigated by transient photobleaching and photoluminescence spectroscopies. Controlling the same number of attached BQ acceptor molecules per NC induces the same ηET in NC-BQ complexes even though with different NC sizes. Our findings provide new insights into ultrafast charge transfer behaviors in perovskite NCs, which is important for designing efficient light energy conversion devices.

Energy and exergy analysis of an ideal molten carbonate fuel cell (MCFC) and reheat & regenerative braysson cycle hybrid system

Direct energy conversion devices are gaining prominence because of their high efficiency, as the process involves the direct conversion of chemical energy to its electrical counterpart, bypassing the thermal energy phase. Fuel cells work on the principle of a chemical reaction between fuels like Hydrogen, Methane, propane, ammonia, and an oxidizer. The working temperature of the fuel cell is as high as (600 °C–700 °C). Generally, waste heat liberated from the fuel cells was used to generate power by running the Brayton (or) Rankine cycle. This work involves exergy and energy analysis on a hybrid system made of a Molten Carbonate Fuel Cell and reheat & regenerative Braysson cycle. Combining a molten carbonate fuel cell (MCFC) with a Braysson cycle results in a novel hybrid system that offers exciting possibilities for power generation. In the analysis, Molten Carbonate Fuel Cell is assumed to operate at 650 °C, and the turbine inlet temperature (TIT) range of the Braysson cycle is taken as 400 to 600 °C. It has been noticed that different optimum pressure ratio values exist to obtain maximum output of power and maximum efficiencies. Both the exergy and energy efficiencies of the combined cycle increase with the increase in turbine inlet temperature. This combined system depicts maximum energy and exergy efficiency of 96.84% and 95.13%, respectively. Destruction rates of exergy for individual equipment and the total system are also obtained as a function of TIT and pressure ratio. The exergy destruction rates are found to be maximum in the fuel cells. An optimum pressure ratio is found to be 1.4, where fuel consumption is the least and efficiencies are the maximum.

Synthesis of 3D FeS embedded into N, S co–doped carbon nanotube/graphene framework for electrochemical application

Constantly striving to develop a facile and scalable way to construct advanced electrodes is essential for the advancement of batteries and electrocatalysis. In this work, an artful K2FeO4 oxidation cooperated with subsequent annealing process is proposed to produce 3D FeS embedded into N, S co–doped carbon nanotube/graphene (FeS/NSCNT/NSG) framework, which simultaneously achieves successful exfoliation of graphite, effective N, S co–doping and desirable integration of 3D framework by FeS and carbon matrix. The adopted procedure is simple, rapid and recyclable. Furthermore, the obtained FeS/NSCNT/NSG exhibits a unique 3D architecture, high doping level and favorable FeS dispersion status, thus displaying excellent performance towards lithium–ion batteries and oxygen evolution reaction. Undoubtedly, our research opens a new pathway for the development of advanced electrodes for energy storage and conversion devices.