Traditional polymers often encounter capacity limitations due to their low active unit density and suboptimal operating voltages (<1 V vs. Zn/Zn2+). In contrast, bipolar polymers, which integrate the advantages of both n- and p-type polymers, offer the potential to create superior zinc-organic batteries (ZOBs). In this study, we report on a novel bipolar poly(1,5-Naphthalenediamine) cathode material doped with manganese single atoms (MnSA@PN), where C=N/C-N redox sites participate in electron transfer processes, serving as storage sites for both cations and anions. Importantly, MnSA@PN features a unique nanovesicle structure that enhances electrolyte permeability, thereby shortening the ion diffusion pathway. Therefore, the Zn//MnSA@PN full battery demonstrates high capacity (259 mAh g(-1) at 0.1 A g(-1)), an elevated average voltage (1.6 V), and exceptional energy density (185 Wh kg(-1)). This work broadens the electrochemical prospects of bipolar polymers, positioning them as promising materials for cutting-edge ZOBs.

Hydrogen production from wind power is an important method to solve the problem of wind abandonment and improve the utilization rate of wind power. However, the "source" turbulence caused by unstable wind speed and the "load" turbulence caused by sudden load change will adversely affect the stable operation of power-to-hydrogen system and the grid connection stability of wind farm. To solve this problem, a synergistic control strategy between supercapacitor and power-to-hydrogen system is proposed. The strategy is based on the Ensemble empirical mode decomposition algorithm. By making the supercapacitor stabilize the high-frequency component in the turbulence of "source-load", the stability of power-to-hydrogen system is improved, and an optimal allocation method of supercapacitor capacity suitable for the control strategy is proposed. Finally, the effectiveness of the strategy is verified by Simulink simulation.

Injecting CO2 into submarine sediments to form hydrates is one of the potential methods of CO2 sequestration. The transition behavior of CO2 hydrates in porous media is of great practical significance. In this work, CO2 hydrate formation/dissociation in porous media was monitored in real time by a low-field magnetic resonance (MR) system, and a series of dynamic fractal dimensions of the pore space occupied by converted water during the hydrate formation/ dissociation process were obtained based on the transverse relaxation time (T2) distributions. In general, the dimension of the converted water space increases with hydrate formation and decreases with the hydrate dissociation progress. A smaller particle size of porous media and a lower initial water saturation can promote hydrate formation, and the corresponding fractal dimension is higher during the hydrate formation process. There is a special status of the fractal period observed during the hydrate formation/dissociation process, and it is considered the temporally and spatially uniform distribution of hydrate crystal formation/dissociation inside the porous media. These results also indicate the relationships between the hydrate transition progress and the dynamic fractal dimension, which are useful for future works on pore-scale hydrate-bearing transitions during hydrate-based CO2 sequestration.

The advent of power-to-gas (P2G) technology has established an extensive capacity for energy systems to integrate and coordinate renewable energy sources (RES) with other energy suppliers. This paper employs a P2G system to coordinate with a standalone gas-fired generation unit (GFGU) to tackle the adverse impacts of greenhouse gas emissions by reducing CO2 and implementing RES. The exhausted carbon from the gas turbine is directly converted via an on-site carbon capture facility, preventing further transportation of CO2. This work considers the inflow/outflow value of gas molar in detail besides electric and thermal power input/output in each device. The mathematical relationships of all devices are explained thoroughly. The proposed GFGU-P2G utilizes wind turbine and GFGU to decrease the carbon emissions and reduce the wind curtailment. This will occur through exploiting excessive wind energy. Two gas storages of CO2 and CH4 are supplemented to the proposed model to increase the efficiency by charging/discharging gas to the system. Stochastic p-robust is applied to measure the encountered risk by solving the risk-based optimization problem. The risk is alleviated by minimizing regret through obtaining the best possible value of p for the decision-maker. Three cases have been proposed to evaluate the impacts of P2G and gas storage on GFGU with and without considering risk. The results illustrate that using P2G instead of a single GFGU will increment the expected carbon emission by 39 %. Moreover, the expected CO2 emission will decrease by 48 % and 16 % when implementing gas storage compared to standalone GFGU and P2G, separately.

This paper is examined the thermal conductivity (TC) of phase change material (PCM) composite microcapsules with gold nanoparticles (NPs) using molecular dynamics simulation (MDS). These microcapsules are made with aminostaldehyde (C2H5NO) as the wall and bromohexadecane (BrC16) as the PCM. First, the physical equilibrium in simulated samples is examined by the change in the temperature and potential energy of atomic samples. Then, the TC of samples in the presence of external heat flux (HF) and a magnetic field (MF) is examined. The parameters of HF, TC, and viscosity of the simulated samples are investigated to study the thermal behavior. The results show that increasing the external HF from 0.1 to 0.5 W/m(2) increases the simulated sample's HF and TC. Also, the viscosity of the simulated sample decreases with increasing HF from 0.0092 to 0.0085 Pa.s. On the other hand, the HF and TC values are increased by increasing the amplitude of the external MF from 0.1 to 0.5 T. Also, the viscosity increases with the MF amplitude to 0.00098 Pa.s. Finally, by enhancing the frequency of the external MF from 0.01 to 0.05 fs(-1), the values of HF and TC decrease. Also, increasing the MF frequency reduces the viscosity in the simulated samples up to 0.00088 Pa.s.

Metal Li has been considered as one promising anode due to its high theoretical capacity and the lowest redox potential, however its dendrites growth and volumetric changes during cycling easily cause battery failure and safety hazards. Here a three dimensional (3D) porous Cu with pore size of about 5 mu m coated with Zn layer is used as current collector for Li deposition to construct dendrite-free metal Li electrode. The suitable pore size and high stability of 3D Cu is beneficial to decrease local current density and buffer volumetric changes, and the Zn layer can decrease the nucleation overpotential of Li, synergistically induce uniform deposition of Li and effectively suppress the growth of Li dendrites. There is no dendrite appears when the 3D Cu@Zn is used as the current collector even the depositing capacity increases to 4 mAh.cm(-2), and displays smooth surface after Li stripping, however, the Li on Cu appears obvious dendrites and non-uniformity, Li on 3D Cu appears local non-uniformity and some dendrites. The semi-cell Li parallel to 3D Cu@Zn demonstrates stable coulombic efficiency at 0.5 and 1 mA.cm(-2) with a capacity of 1 mAh.cm(-2), the symmetrical cell Li parallel to 3D Cu@Zn@Li stably cycle for above 700 h at high current density of 2 mA.cm(-2) with a capacity of 1 mAh.cm(-2). The full cell with 3D Cu@Zn@Li as anode and LiFePO4 as cathode remains 88 mAh.g(-1) after 150 cycles, which is much better than those using Cu@Li plate and 3D Cu@Li as the anodes.

Integrating energy storage systems into electricity distribution systems can improve flexibility, stability and reliability. This issue becomes even more important in renewable resources-assisted energy production systems; because such systems are less reliable due to the intermittent nature of renewable resources. Carnot battery energy storage is a relatively new and emerging approach that is able to solve many challenges of available storage technologies (cost and geographical dependencies). In this regard, in the present article a Carnot battery based on pumped thermal energy storage system (PTESS), organic Rankine cycle (ORC) and vapor heat pump (VHP) has been assessment and discussed in two different modes from the perspectives of thermodynamics, exergy, costing and optimization. In the first case, both charge and discharge modes have a waste heat recovery process (using a regenerator). However, in the latter case, both mentioned modes do not have a waste heat recovery process. Therefore, the purpose of the current article is to examine and compare two different modes of a Carnot battery. Additionally, the minimum value of Levelized cost of storage (LCOS) (as an objective problem) is determined based on the artificial bee colony algorithm. The outcomes revealed that at 120 degrees C, the LCOS and net investing cost values for the considered storage configuration were almost 0.293 USD/kWh and 5450 thousand USD. Furthermore, a comparison of the considered storage configuration with the no-regenerators mode confirmed that the embedding of regenerators in both the charge and discharge sub-cycles could reduce the LCOS value by nearly 10 %.

The fabrication of heterojunction has been considered to be a promising approach to constructing effective photocatalysis systems. Herein, a series of CoTiO3/g-C3N4 heterojunctions denoted as CTO/CN-X were in-situ calcined by adjusting the weight percentage of the starting materials of core-shell Zif-67@TiO2 and melamine.The selection of Zif-67@TiO2 and melamine as starting materials merited a good dispersibility of CoTiO3 on the g-C3N4 sheets owing to the hydrogen bond interactions between melamine and functional groups from Zif-67@TiO2. Attractively, CTO/CN-2 exhibited an excellent methyl orange degradation activity under visible light irradiation (lambda > 420 nm). The degradation process was proved to be a first order kinetics with a kinetics constant of 0.990820.99082 h(-1), which was 38.1, 6.1 times that of g-C3N4 and CoTiO3, respectively. Further investigation reveals revealed that CTO/CN adopted a S-scheme charge transfer route that simultaneously acquire high redox ability and broaden solar energy utilization. This work provides a feasible heterojunction construction strategy by using MOFs as precursors. (c) 2022 Published by Elsevier B.V.

A unique three-dimensional???3D??? porous Zn-Sn alloy electrode was conducted by electrodepositing Sn-Zn alloy on the 3D porous Cu formed from electroless plating to issue the dendrites growth and corrosion of Zn-based electrodes. The 3D porous structure with high stability and suitable pore size of about 5 mu m can reduce the local current density and provide uniform current distribution??? thus induce uniform growth of zinc and reduce the formation of rough dendrites. The element Sn in this alloy can enhance the anticorrosion behavior through increasing the over- potential of hydrogen evolution??? simultaneously induce uniform Zn deposition with less dendrite through decreasing the Zn nucleation energy barrier and providing abundant Zn nucleation sites. The symmetrical cell using two identical 3D porous Sn-Zn electrodes stably cycle for more than 1200 h with a small voltage hysteresis of 21.3 mV at 0.5 mA/cm(2). In contrast??? the symmetrical cell assembled using zinc foil???2D Zn??? appears obvious voltage fluctuation after cycling for 300 h with a larger voltage hysteresis of 99.2 mV. The full cell is stable up to 2000 cycles at 1.8 A/g current.

Hydrogen is one of the leading energy sources under special consideration due to its sustainability and technological development. The main concept of integrated energy system is applied in this article. The goal is to maintain a coordination between hydrogen cycle where hydrogen is produced and converted with renewable energy (RE). Three energy storage for charging/discharging hydrogen, hot and cold water are employed enhance the energy efficiency. The demand-side energy system could rely on this combination that enables the increase in wind and solar energy utilization and uses it to generate hydrogen in future smart cities. This paper uses a scenario-based stochastic optimization to model the associated uncertainties. The epsilon-constraint and max-min fuzzy methods are used as multi-objective approach to satisfy environmental and economic goals, simultaneously. To analyze the associated risk imposed by multiple uncertain parameters, the downside risk constraint (DRC) is implemented to render several risk-averse strategies to the decision-maker based on various constraint level. The results show that the final solution in risk neutral strategy satisfies both emission and operation costs. The ultimate associated risk in conservative strategy will tend to zero at the 4.2% operation cost increment and 3% emission reduction.

Gas hydrates are widely considered as promising candidates for gas storage, energy transportation and seawater desalination. Critical to such applications is a detailed 3D understanding of hydrate formation. To this end, we employ magnetic resonance imaging (MRI) to non-invasively image the gradual formation of opaque hydrate from CO2 and water in a cylindrical vessel at 1 degrees C and as a function of pressure between 2.0 and 3.5 MPa. A 200 mu m thick dense hydrate layer is consistently observed to form at the gas-water interface accompanied by a similar to 1.4 mm thick porous hydrate layer above it and frequently complex dendritic hydrate formation in the water phase below it. Dissociation is observed to occur preferentially via the thick hydrate layer with the initial hydrate film retained largely intact for an extended period of time. The sequential images of hydrate dissociation inside the water phase are most consistent with a vertical heat and mass transfer controlled hydrate dissociation process. The observed difference between the hydrates formed above and inside the water phase is of mechanistic value in understanding these complex interfacial phase transitions.

The recovery of natural gas from a marine hydrate reservoir is a complicated geological process, involving heat and mass transfer inside hydrate-bearing sediments as well between the overburden and underlying layers. Yet, most attention has been paid merely to the evolution of the hydrate reservoir itself. The idea has been proposed to consider as a whole the hydrate layer together with the overburden and underlying layers. In this work, the enhanced gas production behavior from the hydrate reservoir with an underlying water layer was specifically studied. It is found that the initial pressure propagation from the hydrate layer to the free water layer was very difficult; this thereby dominated the early stage of hydrate dissociation. The following dissociation of hydrate was majorly controlled by the heat supply from the sensible heat of the water layer and the resulting temperature distribution. A stepwise depressurization could significantly help enable a stable production rate, and the accumulative water yield depended strongly on the overall pressure drop, regardless of the process of depressurizing. Injecting heat was limited by the low efficiency of horizontal heat transfer resulting from the long distance and low thermal conductivity. The results are helpful in terms of providing guidance to field tests where there is commonly an underlying water layer and water production is frequently encountered.

MnO2 is regarded as a promising cathode for aqueous rechargeable zinc-ion batteries (ARZBs) due to its high theoretical capacity and high voltage. However, it still faces unsatisfied long-term cycling durability due to the John-Teller effect and the formation of the irreversible phase during cycling. Herein, this issue is addressed by constructing a hybrid cathode with a facile commercial strategy involving a uniform mixture of Bi2O3 and MnO2 nanotubes. The multiple effects of adding Bi2O3 are deeply revealed by means of the electrochemical kinetics test, charge-discharge mechanism investigation, phase and structural evolution analyses, as well as density functional theory (DFT) calculations. It is found that the in situ-formed Bi3+ can not only enhance the structural stability and alleviate the dissolution of Mn3+ by forming Mn-O bonds with MnO2, but also lead to better transport kinetics of Zn2+ by the competitive formation of Bi2Mn4O10 that can inhibit the irreversible ZnMn2O4 produced during the repeated H+ and Zn2+ coinsertion/extraction process. Moreover, the tunnel-like Bi2Mn4O10 can contribute an additional capacity by the insertion of H+. Benefiting from these, the MnO2/Bi2O3 hybrid cathode delivers high capacities of 120 and 80 mAh g(-1) even after 5000 cycles at the current densities of 3000 and 10 000 mA g(-1), respectively. This design provides an effective and scalable pathway to enhance the electrochemical performance of the MnO2 cathode and may speed up the commercial application of ARZBs.

Most of the existing field tests of gas recovery from hydrate-bearing sediments suffer from the difficulty in pressure propagation, leading to a low productivity and energy efficiency. Fracturing has shown enormous potential in the shale gas production; thus in this study, we introduced this technique into the laboratory-scale gas hydrate production. The performance of gas production was investigated through numerically analyzing the gas hydrate dissociation behavior under different fracturing patterns. The results indicate that fracturing can significantly facilitate the pressure propagation in the hydrate sediments with a low intrinsic permeability during depressurization, thereby contributing to a better gas production performance. Fracture depth plays a critical role in promoting the gas production efficiency; the maximal enhancement ratio of average production rate by fracturing could attain 13.1%. Moreover, the contribution of reservoir's sensible heat in hydrate dissociation is limited in the core with a low permeability; timely and sufficient heat supply is thus important for the successive gas production. The findings of this study illustrate the effects of fracturing on enhancing the gas production efficiency of depressurization-induced gas hydrate exploitation; this will provide important guidance for its potential application in the field test of marine and permafrost hydrate reservoir where low permeability is commonly encountered and an enhancing technique is much required.

Ultrathin 2D ammonium vanadate nanosheets were grown on alkali-treated carbon cloth via a facile hydrothermal method. This free-standing cathode enables fast ion/electronic transport and reduces the aggregation of ultrathin ammonium vanadate nanosheets.

The metal ions or conductive macromolecules intercalated hydrated vanadium oxides for aqueous Zn-ion batteries (AZIBs) have received increasing attention in recent years. The strategy for the preparation of the intercalated hydrated vanadium oxides has been achieved great advances but is still a huge challenge. In this contribution, we develop an interface-intercalation method to synthesize the polyanilineintercalated hydrated vanadium pentoxide (V2O5.nH(2)O), denoted as PANI-VOH, as the cathode materials for AZIBs. The prepared PANI-VOH exhibits a 3D sponge-like morphology and the surface area of 190 m(2).g(-1.) The interlayer spacing of VOH is expanded to be 14.1 angstrom, which provides a lot of channels for the rapidly reversible (de)intercalation of Zn2+ ions. The coin-typed Zn//PANI-VOH battery shows the specific discharge capacity of 363 mAh.g(-1) at 0.1 A.g(-1) and stable cycling performance. Furthermore, the specific capacity remains 131 mAh.g(-1) after 2000 cycles at 5 A.g(-1), and the energy density is calculated to be 275 Wh.kg(-1) at 78 W.kg(-1) on the mass of PANI-VOH. The achieved values are comparable to or even much higher than that of the most state-of-the-art V-based cathode materials for AZIBs. The PANI intercalation can shorten the pathways and facilitate the transports for the migration of ions and electrons. Our finding guides a novel strategy for the intercalation of PANI into the layered materials to adjust their interlayer spacing, which exhibits super ions migration efficiency, as the cathode materials for AZIBs and even other multivalent ions batteries. (C) 2021 Elsevier Inc. All rights reserved.

Aqueous rechargeable Zn-ion batteries (ARZIBs) are being extensively investigated for large scale energy storage applications owing to their high safety, low cost, sustainability and environmental friendliness. Tremendous attention has been paid to developing the high capacity cathode materials, with stable host structures and fast channels for diffusions of Zn2+ giving rise to high performance. Herein, we report (NH4)(2)V3O8 nanoparticles encapsulated into amorphous carbon matrix [denoted as (NH4)(2)V3O8/C] as a high capacity cathode for ARZIBs, for the first time. It is demonstrated to exhibit much enhanced overall electrochemical performance, including high capacities of 356, 327, 299, 261 and 232 mA h g(-1) at 0.1, 0.2, 0.3, 0.4 and 0.5 A g(-1), respectively, high rate capacity as well as excellent cycle lifespan with 212 mA h g(-1) after 50 cycles at 0.1 A g(-1), 201 mA h g(-1) after 100 cycles at 0.2 A g(-1), and 135 mA h g(-1) after 2000 cycles at 1 A g(-1), respectively. The Zn//(NH4)(2)V3O8/C battery thus assembled delivers a high energy density of 334 Wh kg(-1) at 294 W kg(-1), which are superior to some of the state-of-the-art cathode materials for ARZIBs. In parallel with the electrochemical performance demonstrated, we have clarified the key reaction mechanisms involved in the reversible (de)intercalation of Zn2+, studied by multiple analytical methods.

The key to improve the performance of heteroatom catalysts is to ensure the orderliness of catalysts and the good dispersion of heteroatoms. The alkalinity plays the indispensable role in synthetic process of V-MCM-41 catalyst. The excessive alkalinity of synthetic system will make the MCM-41 difficult to crystallize, even to dissolve. It is easy to accumulate for heteroatomic species in the system of low alkalinity. Herein, the highly ordered V-MCM-41 with high vanadic content in framework is synthesized in the condition of excessive NH3·H2O in this paper. A series of characterization results prove the good dispersion of vanadium species, and most of vanadium gets into the framework of MCM-41 with the states of tetravalence and pentavalence. Furthermore, the modified MCM-41 by other transition metals is successful synthesized by the method of V-MCM-41 in this paper. The V-MCM-41 shows well catalytic activity for the selective oxidation of benzyl alcohol, which up to 74.83% for the conversion of benzyl alcohol and 96.20% for selectivity of benzaldehyde when initial V/Si=0.10. The paper pro-vides the possibility for industrial application of V-MCM-41 in the oxidation of benzyl alcohol for benzaldehyde. Besides, the work provides a significant idea for the synthesis of modified MCM-41 by well-dispersed transition metals.

There have been several trial production tests carried out from marine natural gas hydrate reservoir recently, showing its great potential as an alternative source of energy. Yet an unsustainable production with low productivity and short duration is generally encountered. The marine hydrate reservoirs are mostly highly water-saturated; the resulting water production behaviors remain largely unclear. In this work, the gas and specially water production from a water-saturated reservoir were investigated. The role of water acting as a diffusion barrier of gas was determined: a higher water yield will significantly improve the following gas production. The step-wise depressurization was found to help relieve the initial water production compared with the straight-forward depressurization scenario. A high-water-production stage was for the first time identified, accounting for similar to 47% of the total water production. A further controlled depressurization with finer steps in this stage could enhance the gas productivity by at most 31%; yet its effect on controlling water production was limited. The cumulative water yield depended much on the overall degree of depressurization, regardless of the number of steps. In order for an enhanced gas production under a regulated water yield, thermal stimulation is introduced in the high-water-production stage. This is found to effectively contribute to an optimized water producing process and an at least 30% decline of water yield under comparable gas productivity. The proposed combination method could be applied in the field tests from water-saturated marine reservoir to achieve a high gaswater ratio and a thereby improved energy and economic efficiency.