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Excellent Energy Storage Performance Achieved in Sr(Sc0.5Nb0.5)O3-Doped Bi0.5Na0.5TiO3-Based Lead-Free Relaxor Ferroelectric Ceramics

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ACS Applied Energy Materials 2024年第5期7卷 2030-2038页

作者： Liu, Jinnan Li, Da Zhao, Weichen Xu, Diming Shi, Zhongqi Liu, Wenfeng Su, Jinzhan Zhou, Tao Chen, Guohua Zhou, Di Electronic Materials Research Laboratory & Multifunctional Materials and Structures Key Laboratory of the Ministry of Education International Center for Dielectric Research School of Electronic Science and Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory for Mechanical Behaviour of Materials Xi’an Jiaotong University Xi’an710049 China State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong University Shaanxi Xi’an710049 China International Research Centre for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China School of Electronic and Information Engineering Hangzhou Dianzi University Hangzhou310018 China Electronical Information Materials Devices Engineering Research Center of Ministry of Education Guangxi Key Laboratory of Information Materials School of Material Science and Engineering Guilin University of Electronic Technology Guilin541004 China

Dielectric energy storage ceramics have received significant attention as the primary component for high-pulse power capacitors. Currently, their development is limited by poor energy storage performance, which affects the miniaturization and lightweighting of electronic devices. In this study, a comprehensive optimization approach was adopted to enhance the storage performance (recoverable energy density Wrec and conversion efficiency η) of 0.8Bi0.5Na0.5TiO3-0.2NaNbO3 (BNT-NN) through component optimization design and repeated rolling process (RRP). A series of Sr(Sc0.5Nb0.5)O3 (SSN) was introduced into BNT-NN to modulate the phase structure and improve the relaxation properties. The repeated rolling process was applied to refine the grain and enhance the dense property to boost the breakdown of the electric field. Following the mentioned strategy, we have succeeded in simultaneously obtaining ultrahigh Wrec (∼7.22 J·cm-3) and outstanding η (∼95.32%) under 515 kV·cm-1 for 0.8(BNT-NN)-0.2SSN (RRP) ceramic. More importantly, the ceramic sample possesses outstanding stability over a wide range of temperatures (25-60 °C) and frequencies (1-100 Hz). This study proposes a viable route to better performance of dielectric ceramics for energy storage, and the outstanding performance of the 0.8(BNT-NN)-0.2SSN (RRP) ceramic indicates its promising applicability in high- and high-pulse-power electronic devices. © 2024 American Chemical Society.

关键词： Energy storage

Experimental Study on Boiling Heat Transfer Characteristics in Helical Coils with Large Coiled Diameters

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SSRN 2024年

作者： Shi, Yanggen Wu, Zhiyuan Li, Kepiao Zhang, Kui Tian, Wenxi Qiu, Suizheng State Key Laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China

The boiling heat transfer characteristics in helical coils were investigated by experimental study. Experimental results indicated that the distribution of wall temperature trended to be more uniform due to weakened influence of centrifugal force and gravity force when the bulk fluid is closed to saturation temperature. Increase in heat flux decreases the quality of ONB (onset of nucleate boiling) while increase in mass flux delay ONB. The heat transfer was dominated by nucleate boiling with quality range of 00.6 in saturated boiling region. The quality of dryou decreases with the increase of pressure and it’s scarcely affected by heat flux. Dryout rends to occur at lower quality with the increase of heat flux at high pressure since redeposition rate decreases at higher pressure and entrainment rate increases due to higher heat flux © 2024, The Authors. All rights reserved.

关键词： Heat flux

Numerical Simulation of Fluid-Particle flow of Jet in Supercritical Water Environment

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SSRN 2023年

作者： Zhang, Chuan Shang, Yuqi Su, Haozhe Ge, Zhiwei Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Supercritical water gasification provides a new approach to the green transformation of coal. Nevertheless, the flow behaviour of the fluid and particles inject into the reactor through the nozzle still warrant further research. In this paper, a three-dimensional numerical simulation of the particle jet in supercritical water environment is carried out using LES-DPM. The simulations focus on the effects of particle size, Stokes number, mass flux ratio and fluid initial velocity on the flow characteristics of the fluid-solid flow. The findings were that as the particle size decreases and the initial fluid velocity increases, the evolution of vortex structures became increasingly fierce, such as the destruction of large-scale coherent structures, the disappearance of vortex ribs, and the lateral expansion of vortices in the development section. Particle distribution exhibited characteristics similar to the vortex structure due to particles stuck closely with the carrier fluid when Stokes number is small (St1), the particles were freer from fluid interference and kept their original motion state moving forward. The fluid velocity at the center of the transverse interface jet decreased with increased mass flow ratio. © 2023, The Authors. All rights reserved.

关键词： Vortex flow

Experimental Study on the Plate-Type Fuel Melting Behaviors Based on Alternative Materials

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SSRN 2024年

作者： Wu, Zhiyuan Li, Kepiao Zhang, Kui Chen, Ronghua Tian, Wenxi Qiu, Suizheng State Key Laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China

In this paper, low-temperature experiments are carried out on the visualized experimental device to study the melting behavior of plate-type fuel in severe accidents of the reactor. In the experiments, the plate-type fuel with different sizes made of nickel-chromium alloy, zinc and aluminum was used to carry out the visualized experiments in air, argon, and vacuum environment. It was found that both the size of the plate and the experimental environment have a significant influence on the melting behavior in this study. And the temperature distribution, melting behavior characteristic, the key parameters such as foaming position, foaming size, breaking position and breaking size were also obtained. Based on the experimental data, the physical phenomena and processes related to the blistering and melting of the fuel plates are analyzed in this paper, which provides experimental data support for the development of analysis model and formulating perfect mitigation strategies for severe accidents. © 2024, The Authors. All rights reserved.

关键词： Melting

Manipulating metal-oxygen local atomic structures in singlejunctional p-Si/WO_(3) photocathodes for efficient solar hydrogen generation

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Nano Research 2021年第7期14卷 2285-2293页

作者： Wu Zhou Chung-Li Dong Yiqing Wang Yu-Cheng Huang Lingyun He Han-Wei Chang Shaohua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityShaanxi 710049China Department of Physics Tamkang UniversityTamsui 25137TaiwanChina

Self-passivation in aqueous solution and sluggish surface reaction kinetics significantly limit the photoelectrochemical(PEC)performances of silicon-based ***,a WO_(3) thin layer is deposited on the p-Si substrate by pulsed laser deposition(PLD),acting as a photocathode for PEC hydrogen *** to bare p-Si,the single-junctional p-Si/WO_(3) photoelectrodes exhibit excellent and stable PEC performances with significantly increased cathodic photocurrent density and exceptional anodic shift in onset potential for water *** is revealed that the WO_(3) layer could reduce the charge transfer resistance across the electrode/electrolyte interface by eliminating the effect of Fermi level pinning on the surface of *** importantly,by varying the oxygen pressures during PLD,the collaborative modulation of W–O bond covalency and WO6 octahedral structure symmetry contributes to the promoted charge carrier transport and ***,a large band bending at the p-Si/WO_(3) junction,induced by the optimized O vacancy contents in WO_(3),could provide a photovoltage as high as~500 mV to efficiently drive charge transfer to overcome the water reduction ***,by manipulating W–O local atomic structures in the deposited WO_(3) layer,a great improvement in PEC performance could be achieved over the singlejunctional p-Si/WO_(3) photocathodes for solar hydrogen generation.

关键词： silicon local atomic structure water splitting photocathodes hydrogen generation

Novel Catalyst Coatings on Gas Diffusion Layers for Improved Proton Exchange Membrane Water Electrolysis: A Microscopic Analysis of D-Orbital Electron Interactions in Co0.75Ru0.21Ir0.04O0.9

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SSRN 2024年

作者： Wang, Weiding Wang, Hao Zhang, Yan Yang, Suyi Wang, Baoyuan Dong, Wenxuan Li, Lubing Zhang, Lei Su, Jinzhan Guo, Liejin International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering School of Energy & Power Engineering Xi’an Jiaotong University Xi’an710049 China

Proton exchange membrane water electrolysis (PEMWE) has emerged as a reliable water splitting technology in recent years. The oxygen evolution reaction (OER) at the anode, is the rate-determining step in water electrolysis, and therefore, the kinetic and mass transfer performance of the oxygen evolution reaction should be further studied. Efficient electron and water transfer between the catalyst layer (CL) and gas diffusion layer (GDL) is crucial for optimizing PEMWE performance. In this work, Ru-core modified materials were successfully synthesized via a hydrothermal method and then spray-coated onto the surface of the gas diffusion layer. Physical and electrochemical characterization showed that 0.10 mg cm-2 was the optimal dosage of the coating. The single cell with this optimal coating exhibited a well-promoted and outstanding performance that a cell voltage of 1.71 V@1 A cm-2 and an overpotential of 222 mV@10 mA cm-2. This enhancement was primarily attributed to the improved ohmic and mass transfer properties. Specifically, the promotion of kinetic and mass transfer performance was due to the attraction of the empty d-orbitals of Ru, Co, and Ir, which enhanced electron transmission between the catalyst layer (CL) and gas diffusion layer. Physical analysis revealed that the reductive gaseous products caused Co (Ⅲ) to transform to Co (Ⅱ) and the formation of Co3O4 and RuO2 was well-protected by the Co (II)-rich Co3O4 phase due to its reductivity nature. Additionally, the effusion of gaseous products from the solid phase accelerated pore formation, thereby increasing the specific surface area of the material. © 2024, The Authors. All rights reserved.

关键词： Electrolysis

PROCESS MODELING AND ECONOMIC VIABILITY ANALYSIS OF A power-TO-H2-TO-power SYSTEM: CASE STUDY IN CHINA 37

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PROCESS MODELING AND ECONOMIC VIABILITY ANALYSIS OF A POWER-...

37th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2024

作者： Li, Yanxin Dai, Yanbing Han, Xiaoqu Guo, Xuanhua Karellas, Sotirios Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China Qingdao Huaru Energy Technology Company Limited Qingdao China Laboratory of Steam Boilers and Thermal Plants National Technical University of Athens 9 Heroon Polytechniou str. Zografou Greece

ISBN: (纸本)9798331307660

The power sector generates the most significant greenhouse gas emissions in many countries, while renewable energy penetration faces a bottleneck due to its ***, it is imperative to make substantial efforts to promote the penetration of renewable energy sources into the power *** process of hydrogen production with renewable energy sources is becoming increasingly economical as the cost of renewable energy sources, particularly onshore wind, has fallen *** the present work, a power-to-H2-to-power system (PHPS) combining onshore wind power was proposed as a solution for high penetration of renewable energy, which incorporates a large-scale alkaline water electrolyzer, and a gas turbine.A techno-economic study based on NOVO PRO© and GT PRO was carried out and applied to cases in Shaanxi, *** performance and operational characteristics of two types of PHPS with different hydrogen storage methods, PHPS/Tank and PHPS/Cavern, were *** is indicated that when 30% of the fuel of the gas turbine was replaced by hydrogen, the levelized cost of energy (LCOE) of the PHPS/Cavern was 0.0498 €/kWh with an internal rate of return (IRR) of 6.41%, therefore, PHPS/Cavern was economically feasible in ***, the renewable energy utilization and carbon reduction benefits of the PHPS were *** surplus electricity (curtailed electricity) and carbon emissions of the PHPS/Cavern can be decreased by 52% and 12%, respectively, compared to those of PHPS without hydrogen as the energy *** performance of PHPS with different hydrogen substitution ratios was *** analysis was further conducted to investigate the influence of key parameters on the system performance, including wind modules investment, electrolyzer investment, transport distance, and electricity ***, under the future scenarios in China in 2050, the LCOE of PHPS/Cavern can be reduced by 15% as well as the IRR increased by 66%.The result

关键词： Hydrogen storage

Experimental Study on Condensation Heat Transfer Characteristics inside an Inclined Wave-Finned Flat Tube of Direct Air-Cooling System

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Journal of Thermal Science 2021年第2期30卷 432-440页

作者： WANG Haitao TAO Tao MEI Xuesong WANG Haijun GU Hongfang State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong UniversityXi'an 710049China Shaanxi Key Laboratory of Intelligent Robots School of Mechanical EngineeringXi'an Jiaotong UniversityXi'an 710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

In this paper,the condensation heat transfer characteristics of parallel flow and counter flow inside an inclined wave-finned flat tube is investigated *** condensation heat transfer coefficients are analyzed based on the experimental *** of experiments show that condensation heat transfer coefficient decreases as the temperature difference Δt=ts-tw increases and mass flow rate *** parallel flow has a similar development with the counter flow,and the condensation heat transfer coefficient of counter flow is less than that of parallel flow under the same air cooling *** addition,condensation heat transfer coefficient correlations are also obtained under experimental *** calculations agree well with the measured data and the agreement is seen to be within ±4% for the parallel flow and ±5% for the counter flow.

关键词： condensation heat transfer wave-finned fiat tube modified model parallel flow counter flow

A Numerical Study on Convective Condensation of Flue Gas in Tubular Heat Exchangers

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SSRN 2023年

作者： Yang, Kaixuan Yang, Jiahui Da, Yaodong Han, Lei Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China

Accurate calculation of heat transfer process in condensing heat exchanger plays a crucial role in the waste heat recovery. In this study, the convective-condensation heat transfer process in a condensing heat exchanger with five small heat exchangers is analyzed through utilizing a new numerical simulation model. The method that loads the latent heat of vaporization as heat generation rate is adopted. Under the two working conditions in this study, the deviations of outlet temperature between numerical and experimental results are 1.3 and 2.2 K, respectively, while the deviations of total condensate water flow are 8.5% and 5.5%, respectively. Under the drier working condition, the average temperature reduction per row of tubes in the first small heat exchanger where is no condensation is significantly higher than that in the third small heat exchanger where vapor starts to condense, 5.8 and 2.6 K, separately. It indicates that the release of latent heat of vaporization slows down the cooling rate of the flue gas. In the small heat exchanger where vapor starts to condense, the amount of condensate water on the wall of each row of tubes increases first and then decreases slowly along the flow direction of flue gas. © 2023, The Authors. All rights reserved.

关键词： Heat exchangers