Cycling Operation Research Articles

Dominance of Sulfur-Oxidizing Bacteria, Thiomicrorhabdus, in the Waters Affected by a Shallow-Sea Hydrothermal Plume.

The shallow-sea hydrothermal vent at Guishan Islet, located off the coast of Taiwan, serves as a remarkable natural site for studying microbial ecology in extreme environments. In April 2019, we investigated the composition of prokaryotic picoplankton communities, their gene expression profiles, and the dissolved inorganic carbon uptake efficiency. Our results revealed that the chemolithotrophs Thiomicrorhabdus spp. contributed to the majority of primary production in the waters affected by the hydrothermal vent plume. The metatranscriptomic analysis aligned with the primary productivity measurements, indicating the significant gene upregulations associated with carboxysome-mediated carbon fixation in Thiomicrorhabdus. Synechococcus and Prochlorococcus served as the prokaryotic photoautotrophs for primary productivity in the waters with lower influence from hydrothermal vent emissions. Thiomicrorhabdus and picocyanobacteria jointly provided organic carbon for sustaining the shallow-sea hydrothermal vent ecosystem. In addition to the carbon fixation, the upregulation of genes involved in the SOX (sulfur-oxidizing) pathway, and the dissimilatory sulfate reduction indicated that energy generation and detoxification co-occurred in Thiomicrorhabdus. This study improved our understanding of the impacts of shallow-sea hydrothermal vents on the operation of marine ecosystems and biogeochemical cycles.

Engineering the solid electrolyte interphase for enhancing high-rate cycling and temperature adaptability of lithium-ion batteries.

In overcoming the barrier of rapid Li+ transfer in lithium-ion batteries at extreme temperatures, the desolvation process and interfacial charge transport play critical roles. However, tuning the solvation structure and designing a kinetically stable electrode-electrolyte interface to achieve high-rate charging and discharging remain a challenge. Here, a lithium nonafluoro-1-butanesulfonate (NFSALi) additive is introduced to optimize stability and the robust solid electrolyte interface film (SEI), realizing a rapid Li+ transfer process and the structural integrity of electrode materials. The NFSALi-derived thinner, fluorine-rich, and sulfur-containing SEI in nitrile-assisted carbonate electrolytes effectively suppresses the decomposition of valeronitrile solvent during high-rate cycling and wide-temperature operation (-40-55 °C). More importantly, the graphite‖LiNi0.5Co0.2Mn0.3O2 pouch cell demonstrates a capacity retention of 66.88% after 200 high-rate cycles with 3C charging and 5C discharging under a high-temperature condition of 55 °C. This work provides significant guidance to develop inorganic-rich interfacial chemistry for lithium-ion batteries under extreme operating conditions.

Spintronic Artificial Neurons Showing Integrate-and-Fire Behavior with Reliable Cycling Operation.

The rich dynamics of magnetic materials makes them promising candidates for neural networks that, like the brain, take advantage of dynamical behaviors to efficiently compute. Here, we experimentally show that integrate-and-fire neurons can be achieved using a magnetic nanodevice consisting of a domain wall racetrack and magnetic tunnel junctions in a way that has reliable, continuous operation over many cycles. We demonstrate the domain propagation in the domain wall racetrack (integration), reading using a magnetic tunnel junction (fire), and reset as the domain is ejected from the racetrack with over 100 continuous cycles. Both the pulse amplitude and pulse number encoding are shown. By simulating a spiking neural network task, we benchmark the performance of the devices against an ideal leaky, integrate-and-fire neuron, showing that the spintronic neuron can match the performance of the ideal. These results achieve demonstration of reliable integrated-fire reset in domain wall-magnetic tunnel junction-based neuron devices for neuromorphic computing.

Sustainable biodiesel production from waste cooking oil using highly effective CaO/hectorite catalyst: Process optimization, kinetic and thermodynamic studies.

Biodiesel production through trans-esterification reaction requires design of efficient solid catalyst for sustainable use. This study reports a newly prepared CaO/hectorite catalyst for trans-esterification reaction of waste cooking oil (WCO). The catalyst material was prepared by wet impregnation method. Material characterization was done using various advanced instrumentation techniques such as FTIR, 1H/13C NMR, XRD NMR, BET, TGA and FE-SEM. The result of FE-SEM characterization shows the surface heterogeneity in catalytic material. Further, an enhanced BET surface area (142.3 m2 g−1) of CaO/hectorite indicated suitability of material for catalytic applications. Kissinger-Akahira-Sonuse (KAS) computational model was used to evaluate thermodynamic parameters. Response surface methodology (RSM) – Box Behnken model/ANOVA was used to draw the 3D-surface plots and 2D-contour plots for estimation of maximum biodiesel yield. The catalytic trans-esterification shows high biodiesel production (95 %) in an optimized reaction condition (10.5:1 methanol:oil molar ratio, 3.5 % catalyst loading, 57.5 °C reaction temperature and 105 min). It was found that the biodiesel produced from WCO has fuel characteristics complied with that of B100. The catalyst could be reused up to seven consecutive cycles operation resulting biodiesel production (>80 % yield) thus indicating future commercial applications in a sustainable manner.

High energy conversion efficiency and cycle durability of solar-powered self-sustaining light-assisted rechargeable zinc–air batteries system

The issue of energy supply in outdoor and remote areas has become a significant challenge. Solar-powered self-sustaining rechargeable zinc-air batteries (RZABs) offer a viable energy solution for off-grid regions. However, there has been no specific study on the technical compatibility and adaptability of the solar power generation system and RZABs system, as well as the efficiency of energy conversion and storage in such solar-powered RZABs systems. To address these challenges, this study developed a solar-powered self-sustaining photo-assisted RZABs system based on a photo-responsive polyterthiophene (pTTh) cathode. This system employs pTTh with photo-responsive properties as the cathode catalyst for RZABs, which not only significantly reduces the overpotential of the cathode but also enhances the performance of the RZABs and the overall energy conversion efficiency (reaching 16.2 %). In practical applications, the system exhibits excellent stability, operating continuously within a wide temperature range of -15 to 40 °C, and demonstrating a stable cycling operation capability of up to 33 days. It provides reliable, low-cost power support for electronic devices such as mobile phones, flashlights, GPS units, and small pollutant detection systems, greatly improving the practicality of these devices in off-grid areas.

Electrochemical Performances of a Solid Oxide Electrolysis Short Stack Under Multiple Steady-State and Cycling Operating Conditions

Solid oxide electrolysis cells (SOECs) are increasingly utilized in hydrogen production from renewable energy sources, yet high degradation rates and unclear degradation mechanisms remain significant barriers to their large-scale application. Consequently, endurance testing of stacks under various operating conditions and studying the degradation mechanisms associated with these conditions is imperative. However, due to the generally poor performance consistency among stacks, multi-condition data from numerous stacks lack reliability. In this experimental study, having established a specific SOEC stack’s performance and optimal conditions, durability tests under varied conditions, including various current densities, current operation modes (cyclic or constant current), fuel utilization rates, and temperature cycles were conducted. Electrochemical analysis tools like electrochemical impedance spectroscopy and distribution of relaxation time were employed to analyze the causes of voltage fluctuations under high current densities. The results confirmed that the SOEC stack could handle current cycling at low current densities and constant-current electrolysis at high current densities and withstand at least two temperature cycles.

Self‐healing nanocomposite film of polyvinyl alcohol—polyacrylic acid incorporated with iodine

AbstractSelf‐healing polyvinyl alcohol‐polyacrylic acid (PVA‐PAA) composite films incorporated with molecular iodine (I2) are presented for optoelectronic applications. The incorporation mechanism between the PVA‐PAA donor and I2 acceptor is investigated by studying the chemical, crystal, and morphological properties of the composite films. Incorporating PVA‐PAA composite films with I2 decreases the crystallinity degree of the composite films, which increases the electrical conductivity by enabling the segmental motion in the polymer matrix. PVA‐PAA/I2 composite films are stable at temperatures lower than 200°C, where the majority of optical, optoelectronic, and electrical applications can be realized. Additionally, introducing I2 into the PVA‐PAA matrix increases the melting temperature of the composite films. Moreover, the optical and electrical properties of the PVA‐PAA/I2 composite films are investigated. The bandgap energy of PVA‐PAA film is 3.88 eV, decreasing continuously to 3.38 eV as I2 concentration increases to 16 wt.%. On the other hand, The average conductivity of the PVA‐PAA film is . Increasing I2 concentration in the PVA‐PAA matrix increases the electrical conductivity continuously up to . The physical properties of the PVA‐PAA/I2 composite films exhibit self‐healing properties after thermal treatment and UV irradiation that occur during the operation cycling in optical, optoelectronic, and electrical applications.

Phase relationships and thermal behavior of one-pot synthesized dual-phase BaCe0.5Fe0.5O3–δ composites

The synthesis of self-assembled composite materials via a one-pot technique offers a promising strategy for designing modernized electrodes for use in solid oxide electrochemical cells based on both oxygen-ionic and proton-conducting electrolytes. Within the present work, a BaCe0.5Fe0.5O3–δ composite (extensively investigated in the literature as a triple conductor) was prepared as both dense and porous ceramics. The thermal properties of these materials were subsequently characterized via a range of complimentary techniques, including high-temperature X-ray diffraction, thermogravimetry, and dilatometry analyses. The employed methods allow for the refinement of the compositions for both Ce- and Fe-enriched phases, as well as the determination of the thermal expansion behaviors of both the basic components and the composite as a whole. The experimental results demonstrate that the Ce- and Fe-based phases exhibit markedly disparate thermomechanical responses, which represents a significant limitation for the joint application of BaCe0.5Fe0.5O3–δ-derived electrodes with a range of electrolyte representatives. While the thermomechanical discrepancy can be reduced for the porous state of the electrodes, greater attention should be paid to the microstructural integrity of such electrodes and the quality of the electrolyte/electrode interface under long-term and cycling operating conditions. Therefore, this work provides complementary information on the various functional properties of dual-phase BaCe0.5Fe0.5O3–δ composites.

A Thermodynamic Study of Pressure Gain Combustion in Combined Cycles

Abstract Gas turbines are internal combustion engines based on the Brayton-Joule cycle with four thermodynamic processes including air compression, constant pressure combustion, gas expansion and heat rejection. Actually, a relevant increase in entropy production is related to the constant pressure combustion, even in the ideal cycle, so alternative combustion solutions, such as the Pressure Gain Combustion (PGC), are worthy of attention. This work aims at investigating PGC potential in gas turbines compared to conventional power plants based on the Brayton-Joule cycle. Both simple cycle and combined cycle operations are considered, focusing on a F-class gas turbine unit for power production. Cycle performance is estimated through a thermodynamic in-house code, where the common calculation scheme has been revised in order to simulate a combustion process occurring with increasing pressure from inlet to outlet of the combustor. A booster compressor is necessarily included in the power system for delivering the cooling air to the first stage blades of the turbine. The results are fully satisfactory as PGC technology really improves the efficiency of the gas turbine expander: in case of a pressure gain of 45%, which is a reasonable value based on literature data, 1.3 to 3.4 percentage points more in gas turbine efficiency have been calculated. Finally, a parametric analysis of expansion efficiency penalties due to supersonic pulsating flows at the first stage of the turbine expander is presented.

Simplified dynamic modeling and Fuzzy gain scheduled PID control of woodward-governor controlled grid-interactive twin-shaft gas turbine plants

Biomass-integrated gas turbines for electricity generation are competitive with coal and nuclear energy production. Gas turbine-based power generation system looks to be an excellent solution amid the emerging environmental conditions and the increased energy crisis. This paper presents a simplified dynamic analysis model for biomass-based, Woodward governor-controlled, twin-shaft heavy-duty gas turbine (HDGT) plants, alongside an intelligent controller for stability enhancement. Grid-connected HDGTs can become unstable under load disturbances, potentially causing system shutdowns. A simplified model for twin-shaft gas turbines, rated from 18.2 MW to 106.7 MW, has been identified based on control characteristics during startup. The speed controller is dominant, while the acceleration controller is only active at startup, and the temperature controller's effect is minimal during normal operation. This model suits all dynamic studies of twin-shaft gas turbines, regardless of varying power ratings and rotor time constants. For improving the grid stability, a Takagi-Sugeno-Kang (TSK) fuzzy gain scheduling PID controller has been proposed in this work and its behavior is validated with 5001M, 7001Ea, and 9001Ea models. Step response of fuzzy PID controller under load disturbances and set-point variations are compared with fixed gain PID controllers tuned by Ziegler-Nichols (ZN) and performance index-based tuning using the typical gas turbine model. Further the controller behavior is validated with field test-based model parameters as derived from the real-world combustion turbines used in Alaskan Railbelt system. Extensive research simulation and validation results reveal that the fuzzy self-tuning PID controller showed superior adaptability for grid-interactive twin-shaft HDGTs under load variations and set-point variations. Time domain specifications and the performance indices confirms that the proposed fuzzy tuned PID controller ensure reliable and stable operation for the energy management in grid-operative mode. The proposed simplified model and intelligent control logic enable various dynamic studies in grid-connected environments for both simple cycle and combined cycle operations.

Capacity augmentation strategy in α-Fe2O3 nanoparticles through multifaceted structural and electrochemical analyses

Hematite (α-Fe₂O₃) has garnered significant research interest for supercapacitor applications, but capacity fading and limited cyclic life remain serious challenges. In this context, the present research provides a comprehensive study of the factors that significantly impact charge kinetics within the electrode and at the solid/electrolyte interface. By integrating structural and electrochemical analyses, this study offers an effective strategy to enhance the capacity of α-Fe₂O₃ nanoparticles through rigorous scientific analysis and identification of various qualitative and quantitative factors that influence charge storage capacity. A simple one-step co-precipitation method was adopted to synthesize porous α-Fe₂O₃ nanoparticles. The quantitative analysis of charge kinetics demonstrated the domination of diffusion-controlled charge storage as the main contributor to the total charge storage. The α-Fe₂O₃ nanoparticles-based electrode delivered a high energy density of 24.6 Wh kg⁻1 at an impressive power density of 478.7 W kg⁻1. Additionally, it displayed a capacity retention of 79 % over 10,000 cycle operations. The choice of electrode material and the superior porous nanoarchitecture have proven to be advantageous for high-performance supercapacitor applications, offering fast electron/ion transport.

Modeling of performance and thermodynamic study of a gas turbine power plant

The efficiencies and performance of gas turbine cycles are highly dependent on parameters such as the turbine inlet temperature (TIT), compressor inlet temperature (T1), and pressure ratio (Rc). This study analyzed the effects of these parameters on the energy efficiency, exergy efficiency, and specific fuel consumption (SFC) of a simple gas turbine cycle. The analysis found that increasing the TIT leads to higher efficiencies and lower SFC, while increasing the To or Rc results in lower efficiencies and higher SFC. For a TIT of 1400 ℃, T1 of 20 ℃, and Rc of 8, the energy and exergy efficiencies were 32.75% and 30.9%, respectively, with an SFC of 187.9 g/kWh. However, for a TIT of 900 ℃, T1 of 30 ℃, and Rc of 30, the energy and exergy efficiencies dropped to 13.18% and 12.44%, respectively, while the SFC increased to 570.3 g/kWh. The results show that there are optimal combinations of TIT, To, and Rc that maximize performance for a given application. Designers must consider trade-offs between efficiency, emissions, cost, and other factors to optimize gas turbine cycles. Overall, this study provides data and insights to improve the design and operation of simple gas turbine cycles.

Experimental Set‐Up for Measurement of Half‐Cell‐ and Over‐Potentials of Flow Batteries during Operation

The study of flow batteries (FBs) requires the development of tools able to evaluate their performance during operation in a reliable and simple way. In this work, we present an experimental set‐up that allows the on‐line monitoring of the half‐cells state of charge and apparent overpotentials on the positive and negative electrodes during battery operation. These measurements are feasible by using additional flow cells that include a reference electrode on each side. We used the experimental set‐up to study the performance of the vanadium system as well as a previously reported stable organic couple. The studies consisted on short cycling operation at different current densities and polarization curves at different flow rates and states of charge. By confirming previous results obtained for vanadium‐FBs and extending the analysis to further systems, we demonstrated that this approach provides a reliable deeper insight into the battery performance and the processes taking place during operation.

Robust antifouling Poly(ionic liquid)s membrane with cyclodextrin skeleton for separation of oil/water emulsions

Membrane fouling remains a persistent and arduous challenge in the industrial treatment of different surfactants-stabilized oily wastewater. Constructing a robust antifouling and sustainable hydration coating on the membrane surface to efficiently repel oils or surfactants is a critical requirement. Herein, cyclodextrin-based poly(ionic liquid)s (PILs) coatings are cross-linked via the co-deposition on poly(vinylidene fluoride) (PVDF) of quaternized heptkis(6-deoxy-6-vinylimidazolium)-β-cyclodextrin (CD-Vi) derivatives as skeleton and acrylic acid (AA) monomers, and following one-step free radical photopolymerization. Combining with the strong hydration of the CD-based PILs coating, the resultant membrane exhibits fabulous superhydrophilicity and underwater superoleophobicity, oil repulsion, and self-cleaning capability. It demonstrates robust mechanical durability and chemical stability in harsh environments without losing its superhydrophilicity. Besides, the PIL-CD/AA coating can separate various surfactant-free and different surfactants (cationic CTAB, anionic SDS, and nonionic TWEEN 80) stabilized oil / water emulsions. During the long-term cycle operations, it also realizes stable recyclability with a series of permeation fluxes as high as removal efficiencies (>99.6 %) after 20 cycles for surfactant-free cyclohexane-in-water emulsion and 10 cycles for CTAB-stabilized isooctane-in-water emulsion.

Durable high voltage solid-state sodium batteries with Pseudocapacitive P2 layered oxide cathode

Solid-state sodium batteries (SSBs) have attracted great interests due to their high energy density, good safety and low cost, but their performance including operation voltage, cycling stability and rate capability are far from satisfactory. In this study, a P2-Na0.68Li0.10Ni0.25Mn0.63Ca0.01Ti0.01O2 (NM-L10CT) layered cathode material were successfully fabricated, which possesses a high pseudocapacitance over 92 %, low volume strain of 0.8 %, high Na-ion diffusion coefficient and very good reversibility of anionic redox reaction. Moreover, room temperature solid-state sodium batteries with NM-L10CT and Na3Zr2Si2PO12 (NZSP) solid electrolyte are demonstrated, displaying much improved structural stability and cycling performance compared with that in liquid electrolyte batteries. The NM-L10CT/NZSP/Na SSBs exhibit very excellent electrochemical performance under high cut-off voltage, with high retention rates of 81.2 % after 500 cycles (2.0–4.2 V) and 74.2 % after 300 cycles (2.0–4.3 V), respectively. It has an outstanding rate performance with a high capacity of 115.4 mAh g-1 at 1 C and 74.5 mAh g-1 even at 10 C rate. This is due to the significantly reduced interface resistance and improved structural stability in solid state. This work demonstrates the successful application of high voltage layered cathode in SSBs and provides the insightful understanding of such material in liquid electrolyte and solid state battery.

Recyclable wood-structured bimetallic carbon aerogel for high-performance bulk catalytic antibiotic decomposition

Harnessing renewable low-cost, bulk wood-structured materials with highly porous, anisotropic and compressible properties that fulfills sustainable water purification is imperative yet still challenging to push forward a circular bioeconomy. In this work, a bimetallic Fe-Co implanted, N-doped wood carbon aerogel (Fe-Co/NWCA) is constructed to guarantee the facile regeneration in high-performance catalytic antibiotic decomposition via activating peroxymonosulfate (PMS). A rapid, reversible and excellent tetracycline (TC) elimination performance (∼90% in 12 min) within a wide pH range of 3–11 is achieved by Fe-Co/NWCA-mediated system. Importantly, the as-prepared hydrophilic Fe-Co/NWCA not only delivers a favorable robustness to interfering anions (e.g., Cl−, H2PO4− and HCO3−), but also presents a superior recyclability with over 90% retention after the fourth cycling operation via a convenient squeezing behavior. Integration of radical quenching experiments and electron paramagnetic resonance demonstrates the participation of reactive oxygen species (ROS) into catalytic TC oxidation, wherein the dominant contributor is 1O2 followed by O2•‾, SO4•‾ and •OH. As an important non-radical route, the directly interfacial electron transfer is confirmed by electrochemical measurements and density-functional-theory computations. In the context of activating PMS, the multi-valent Fe, Co-coordinated species function as the redox reactive site to trigger diversiform ROS with accelerated kinetics, while N, O-associated surface defects and unsaturated functional groups (e.g., −COOH and ketonic C=O) contribute to the 1O2 formation and electron shuttling. This universal approach paves a critical avenue to manufacture the reactive wood-based aerogels with hierarchical microchannels in the practical pollutant remediation, shedding the valuable insights on multifunctional biomass-water nexus.

A Review of Nanocarbon-Based Anode Materials for Lithium-Ion Batteries

Renewable and non-renewable energy harvesting and its storage are important components of our everyday economic processes. Lithium-ion batteries (LIBs), with their rechargeable features, high open-circuit voltage, and potential large energy capacities, are one of the ideal alternatives for addressing that endeavor. Despite their widespread use, improving LIBs’ performance, such as increasing energy density demand, stability, and safety, remains a significant problem. The anode is an important component in LIBs and determines battery performance. To achieve high-performance batteries, anode subsystems must have a high capacity for ion intercalation/adsorption, high efficiency during charging and discharging operations, minimal reactivity to the electrolyte, excellent cyclability, and non-toxic operation. Group IV elements (Si, Ge, and Sn), transition-metal oxides, nitrides, sulfides, and transition-metal carbonates have all been tested as LIB anode materials. However, these materials have low rate capability due to weak conductivity, dismal cyclability, and fast capacity fading owing to large volume expansion and severe electrode collapse during the cycle operations. Contrarily, carbon nanostructures (1D, 2D, and 3D) have the potential to be employed as anode materials for LIBs due to their large buffer space and Li-ion conductivity. However, their capacity is limited. Blending these two material types to create a conductive and flexible carbon supporting nanocomposite framework as an anode material for LIBs is regarded as one of the most beneficial techniques for improving stability, conductivity, and capacity. This review begins with a quick overview of LIB operations and performance measurement indexes. It then examines the recently reported synthesis methods of carbon-based nanostructured materials and the effects of their properties on high-performance anode materials for LIBs. These include composites made of 1D, 2D, and 3D nanocarbon structures and much higher Li storage-capacity nanostructured compounds (metals, transitional metal oxides, transition-metal sulfides, and other inorganic materials). The strategies employed to improve anode performance by leveraging the intrinsic features of individual constituents and their structural designs are examined. The review concludes with a summary and an outlook for future advancements in this research field.

Engineering mineralized interlayers for enhanced nanofiltration: Synergistic modulation of polyamide layer structure and catalytic self-cleaning performance

High permselectivity and antifouling/self-cleaning nanofiltration (NF) membranes are ideal materials for water treatment, and this vision is expected to be reached through the design of multifunctional self-cleaning interfaces. In this study, we employed metal - polyphenol network (MPN) to mediate in situ mineralization of porous substrates, enabling simultaneous modulation of interfacial polymerization (IP) and catalytic self-cleaning. The findings demonstrate that the mineralized layers employ an interlayer modulation strategy to produce a polyamide (PA) layer that is more hydrophilic, thinner, and structurally denser. As a result, the resulting PA-Fe3O4-PSF membrane exhibited a 2.5-fold increase in permeance (19.2 L m−2 h−1 bar−1) and a 7.3-fold enhancement in Cl−/SO42− selectivity (66.4), compared to the control membrane (PA-PSF). Additionally, its highly polarized membrane surface significantly improved its antifouling performance. Compared to membranes with mineralized layers on the surface (Fe3O4-PA-PSF), PA-Fe3O4-PSF constructs a confined space that facilitates more efficient regeneration through in situ catalytic self-cleaning and ensures greater stability during multiple fouling-regeneration cycle operations. This study paves the way for fabricating multifunctional NF membranes with sustainable applications in material concentration, wastewater treatment, and environmental remediation.

Coupling optimization of protruding fin and PCM in hybrid cooling system and cycle strategy matching for lithium-ion battery thermal management

Based on liquid cooling and phase change material (PCM), a fin-enhanced composite thermal management system suitable for high power and extended cycle operations of lithium-ion battery module at high ambient temperature is proposed in this work. The coupling effect between the protruding fin structure and PCM thickness, as well as the addition of expanded graphite to the PCM, are investigated to optimize hybrid cooling arrangement. The results show that synergistic optimization of the protruding fin structure and PCM arrangement can enhance heat diffusion from the batteries to the cooling water, improve PCM utilization, and ensure sufficient latent heat. And then, the expanded graphite-modified PCM can make heat absorption and phase transition more uniform, and battery temperatures can be further decreased by up to 7.45 °C with 16 wt% expanded graphite. Clearly, the coupling optimization improves the cooling performance and applicability of conventional thermal management systems, while the temperature difference and maximum temperature in the optimized system have been regulated to within 4.30 °C and 46.78 °C under 40 °C environment and 5C discharge, respectively. Moreover, the cyclic charging and discharging strategies are designed and matched, and using the matching strategy with a fixed charge or discharge rate of 1C provides lower temperatures and better temperature uniformity, which can always control the temperatures below 47.22 °C and temperature difference below 4.69 °C. The optimized system with cycle strategy matching ensures the repeatability of battery operation and provides cooling solutions for different application scenarios.

Enhancement of redox cycling stability of Ni/GDC cermets for intermediate-temperature SOFC anodes through Ge incorporation in the ceramic phase

In this study, Ge4+ was incorporated into the ceramic matrix of nickel-based anode materials, synthesizing anode materials NiO-Gd0.1Ce0.9-xGexO1.95 (x = 0.01, 0.04, 0.07) and NiO-Ce0.9Gd0.1O2–δ. Corresponding anode support samples were also prepared, designated as A-CGDC, A-C1Ge, A-C4Ge, and A-C7Ge. Additionally, single cell samples using the newly co-doped anode materials were prepared, identified as C-CGDC, C-C1Ge, C-C4Ge, and C-C7Ge. The research indicates that after doping the ceramic phase framework with Ge4+, these composite anode materials exhibit the potential to withstand more redox cycles than C-CGDC without catastrophic mechanical structural damage or degradation in electrochemical performance. Particularly, after incorporating 7mol% Ge4+ into the ceramic backbone, the issue of 86 % strain accumulation in the anode support was mitigated. Additionally, the ion doping ratio is closely linked to the stability of the single cell samples, with the A-C7Ge sample able to withstand up to 11 extreme recycling sessions at 700 °C without complete structural failure, improving structural stability by approximately 57 % compared to A-C1Ge. In terms of electrochemical output performance, the impedance of C-C1Ge prior to complete failure was nearly double that before oxidation-reduction, with a maximum power density reduction of about 26.47 %. As the co-doping concentration in the ceramic phase reached 7mol%, the impedance increase during single cell cycle testing was about four times smaller, with C-C7Ge 's impedance before mechanical failure only 37 % higher than before cycling, and a reduction in maximum power density of just 11.11 %. Moreover, during consecutive cycling tests, the average damage to the open-circuit voltage was only 0.02V, showing almost no negative impact from the cycling operations, and it maintained efficient output performance after multiple cycles. Therefore, the newly synthesized nickel-based anode materials, modified via co-doping methods within the ceramic phase, can be considered as potential composite anode materials for intermediate-temperature solid oxide fuel cells.