As a mixed ion-electronic conductor, doped ceria, especially rare earth doped ceria, were used as anodes or components of anodes in SOFCs. In this work, calcium doped ceria （CCO） was synthesized to be used in interm...As a mixed ion-electronic conductor, doped ceria, especially rare earth doped ceria, were used as anodes or components of anodes in SOFCs. In this work, calcium doped ceria （CCO） was synthesized to be used in intermediate-temperature SOFCs （IT-SOFCs） anodes in order to reduce the cost of anode-supported SOFCs. Electrical conductivity of 20% calcium doped ceria （20CCO） reached 0.209 S·cm^-1 in hydrogen at 850 ℃, and 0.041 S·cm^-1 in air at 800℃, which is about 0.04 S·cm^-1 lower than that of conventional samaria-doped ceria （0.079 S·cm^-1）. Electrochemical performance of Ni-20CCO cermet as anode was investigated using a fuel cell with 35μm-thick SDC electrolyte and Sm0.5Sr0.5 Co-SDC cathode. Maximum power density was 623 mW·cm^-2 under humidified （3% H2O） hydrogen at 650 ℃, inferring high catalytic activity of the Ni-20CCO anode.展开更多
This study focuses on the impact of Gd^(3+),Sm^(3+),Er^(3+).Y^(3+),and Bi^(3+)multi-doping on the crystal structure,microscopic surface features,and ionic conductivity of cerium dioxide in the Ce_(1-x)(Gd_(1/5)Sm_(1/5...This study focuses on the impact of Gd^(3+),Sm^(3+),Er^(3+).Y^(3+),and Bi^(3+)multi-doping on the crystal structure,microscopic surface features,and ionic conductivity of cerium dioxide in the Ce_(1-x)(Gd_(1/5)Sm_(1/5)Er_(1/5)Y_(1/)_5Bi_(1/5))_(x)O_(2-δ)(GSEYB)system.This system holds promise as a solid electrolyte material for low and medium-temperature solid oxide fuel cells.The powders of Ce_(1-x)(Gd_(1/5)Sm_(1/5)Er_(1/5)Y_(1/5)Bi_(1/5))_(x)O_(2-δ)(x=0,0.10,0.15,0.20,0.25,0.30)were synthesized using the solid-phase reaction method.The GSEYB electrolytes were comprehensively investigated for their phase structure,microstructure,oxygen vacancy concentration,and ionic conductivity using X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),and impedance spectroscopy.XRD diffraction patterns confirm a cubic fluorite-type structure with Fm3m space groups in all multi-doped systems.After sintering at 1400℃for 10 h,the relative density of doped samples exceeds 96%.In terms of electrical properties,the Ce_(0.75)Gd_(0.05)Sm_(0.05)Er_(0.05)Y_(0.05)Bi_(0.05)O_(2-δ)(x=0.25)electrolyte exhibits the highest ionic conductivity(σ_(t)=4.45×10^(-2)S/cm)and the lowest activation energy(E_(a)=0.79 eV)at 800℃.The coefficient of thermal expansion of the developed electrolyte aligns well with that of the commonly used electrode materials.This compatibility positions it as a highly promising candidate for utilization as an electrolyte material in solid oxide fuel cells(SOFCs).展开更多
The development of cost-effective solid oxide fuel cells(SOFCs)is crucial for the large-scale application.In this study,anode-supported SOFC single cells were fabricated using a combination of slurry spraying and spin...The development of cost-effective solid oxide fuel cells(SOFCs)is crucial for the large-scale application.In this study,anode-supported SOFC single cells were fabricated using a combination of slurry spraying and spin-coating technique to achieve a dense Yttria Stabilized Zirconia(YSZ)electrolyte layer while maintaining low production cost.The electrochemical performance of the fabricated SOFC was evaluated using hydrogen and dry methane as fuels.Microstructural analysis confirmed that the YSZ electrolyte exhibited high densification with a thickness of approximately 10μm,ensuring excellent gas-tightness and preventing fuel crossover.The NiO-YSZ anode demonstrated favorable porosity,with well-sintered NiO particles forming a robust framework to facilitate electrochemical reactions.Performance evaluations revealed that under hydrogen operation,the SOFC achieved a peak power density of 1.408 W/cm^(2)at 1000℃,with open-circuit voltages(OCVs)closely matching theoretical predictions.When operated with dry methane,the SOFC maintained stable performance,reaching a peak power density of 0.96 W/cm^(2)at 1000℃,highlighting its potential for direct hydrocarbon utilization.Gas composition analysis of the anode exhaust confirmed the absence of excessive carbon deposition,indicating the effectiveness of the anode microstructure in mitigating coking during methane oxidation.These findings demonstrate that the spray-coated and spin-coated SOFC design offers a promising approach to improving fuel cell efficiency and cost-effectiveness.Future research should focus on optimizing electrolyte fabrication methods and enhancing anode stability in hydrocarbon-fueled operation to further advance the commercialization of SOFC technology.展开更多
A sol-gel method and a modified chemical vapour deposition technique were used to produce nanostructured Ce0.6Sr0.4Fe0.8Co0.2O3-δ materials at temperatures as low as 400 ℃. Powders were characterized using Fourier t...A sol-gel method and a modified chemical vapour deposition technique were used to produce nanostructured Ce0.6Sr0.4Fe0.8Co0.2O3-δ materials at temperatures as low as 400 ℃. Powders were characterized using Fourier transform infrared spectroscopy （FTIR）, Raman spectroscopy, thermo gravimetric analysis, powder X-ray diffraction （XRD）, scanning electron microscopy （SEM） with energy dispersive X-ray spectroscopy, high resolution transmission electron microscopy （HRTEM）, and nitrogen sorption at 77 K. FTIR spectra showed that the sol-gel method resulted in residual carbon groups on the materials after calcination, while the Raman and XRD analysis confirmed that both synthesis methods resulted in cubic perovskite structure. However, the chemical va- pour deposition （CVD） method resulted in materials with a smaller crystallite size when compared to those prepared via the sol-gel route. The overall morphology of the powders was irregularly shaped aggregated particles as observed by SEM and HRTEM. In addition, HRTEM analysis showed that the materials were highly crystalline. Textural analysis revealed the powders had some mesoporosity, and the surface areas were 76.69 and 65.90 m2/g for materials synthesized using the CVD and sol-gel methods, respectively. The synthesized perovskite powders were used to fabricate button cells employing samarium doped ceria （SDC） as the electrolyte and NiO/SDC as the anode materials. As cathode materials, the maximum power density observed was 308.4 mW/cm2 at 500℃.展开更多
High-entropy alloys(HEAs)have attracted tremendous attention owing to their controllable mechanical properties,whereas additive manufacturing(AM)is an efficient and flexible processing route for novel materials design...High-entropy alloys(HEAs)have attracted tremendous attention owing to their controllable mechanical properties,whereas additive manufacturing(AM)is an efficient and flexible processing route for novel materials design.However,a profound appraisal of the fundamental material physics behind the strengthening of AM-printed HEAs upon low/intermediate-temperature annealing is essential.In this work,Co CrFe Ni Mn HEAs have been prepared using laser-engineered net shaping(LENS)and subsequently annealed at different temperatures.The Co Cr Fe Ni Mn HEA annealed at intermediate-temperature(873 K)exhibits a strong strain hardening capability,resulting in ultimate strength of 725 MPa and plasticity of 22%.A ternary heterogeneous strengthening mechanism is proposed to explain this phenomenon,in which equiaxed grains,columnar grains,andσprecipitates play different roles during tensile deformation.The resultant excellent strength and ductility can be ascribed to the heterostructure-induced mismatch.The equiaxed grains provide adequate grain boundaries(GBs),which induce dislocation plugging-up and entanglement;the columnar grains induce the onset and arrest of the dislocations for plastic deformation;and theσprecipitates hinder the movement of slip dislocations.The results provide new insights into overcoming the strength-ductility trade-off of LENS-printed HEAs with complex geometries.展开更多
New cobalt-free composites consisting of Ba0.5Sr0.5Fe0.9Ni0.1O3-δ （BSFN） and Ce0.8Sm0.2O2-δ （SDC） were investigated as possible cathode materials for intermediate-temperature solid oxide fuel cell （IT-SOFC）. B...New cobalt-free composites consisting of Ba0.5Sr0.5Fe0.9Ni0.1O3-δ （BSFN） and Ce0.8Sm0.2O2-δ （SDC） were investigated as possible cathode materials for intermediate-temperature solid oxide fuel cell （IT-SOFC）. BSFN, which was synthesized by auto ignition process, was chemically compatible with SDC up to 1100 ℃ as indicated by X-ray diffraction analysis. The electrical conductivity of BSFN reached the maximum value of 57 S.cm-1 at 450 ℃. The thermal expansion coefficient （TEC） value of BSFN was 30.9×10-6 K-1, much higher than that of typical electrolytes. The electrochemical behavior of the composites was analyzed via electrochemical impedance spectroscopy with symmetrical cells BSFN-SDC/SDC/BSFN-SDC. The area specific interracial polarization resistance （ASR） decreased with increasing SDC content of the composite. The area specific interracial polarization resistance （ASR） at 700 ℃ is only 0.49, 0.34 and 0.31 Ω.cm2 when 30, 40, and 50 wt% SDC was cooperated to BSFN, respectively. These results suggest that BSFN-SDC is a possible candidate for IT-SOFC cathode.展开更多
A new cathode material fabricated by solid state reaction method was reported. The SmVO4 powder was obtained by firing the mixture of Sm2O3 and V2O5 powders in the temperature range of 700-1200 ℃. Its structure was i...A new cathode material fabricated by solid state reaction method was reported. The SmVO4 powder was obtained by firing the mixture of Sm2O3 and V2O5 powders in the temperature range of 700-1200 ℃. Its structure was identified by X-ray diffraction method and the electrochemical properties of SmVO4 as cathodes for solid oxide fuel cells (SOFCs) were investigated in single unit cell at the temperature ranged from 450-550 ℃. The results of the single fuel cell unit show that the maximum current densities are 641, 797, 688 mA·cm-2 and the maximum power output are 165, 268, 303 mW·cm-2 and the open circuit voltage are 1.04, 0.96, 0.92 V at 450, 500 and 550 ℃, respectively.展开更多
Carbon capture,utilization and storage(CCUS) is widely recognized as a vital strategy for mitigating the impact of human induced climate change.Among various CO_(2) adsorbents,intermediate-temperature solid adsorbents...Carbon capture,utilization and storage(CCUS) is widely recognized as a vital strategy for mitigating the impact of human induced climate change.Among various CO_(2) adsorbents,intermediate-temperature solid adsorbents have garnered significant attention due to their potential applications in hydrogen utilization,specifically in the water gas shift,steam reforming and gasification processes.These processes are crucial for achieving carbon neutrality.While laboratory-level studies have showcased the high adsorption capacity of these materials via various synthesis and modification methods,their practical application in complex industrial environments remains challenging,impeding the commercialization process.This review aims to critically summarize the recent research progress made in intermediatetemperature(200-400℃) solid CO_(2) adsorbents,particularly focusing on indicators such as cyclability,gas selectivity,and formability,which play vital roles in industrial application scenarios.Additionally,we provide an overview of laboratory-level advanced technologies specifically tailored for industrial applications.Furthermore,we highlight several industrial-ready advanced technologies that can pave the way for overcoming the challenges associated with large-scale implementation.The insights provided by this review aim to assist researchers in identifying the most relevant research directions for industrial applications.By promoting advances in the application of solid adsorbents,we strive to facilitate the ultimate goal of achieving carbon neutrality.展开更多
To explore highly active and thermomechanical stable air electrodes for intermediate-temperature solid oxide fuel cells(ITSOFCs),10mol%Ta5+doped in the B site of strontium ferrite perovskite oxide(SrTa_(0.1)Fe_(0.9)O_...To explore highly active and thermomechanical stable air electrodes for intermediate-temperature solid oxide fuel cells(ITSOFCs),10mol%Ta5+doped in the B site of strontium ferrite perovskite oxide(SrTa_(0.1)Fe_(0.9)O_(3-δ),STF)is investigated and optimized.The effects of Ta^(5+)doping on structure,transition metal reduction,oxygen nonstoichiometry,thermal expansion,and electrical performance are evaluated systematically.Via 10mol%Ta^(5+)doping,the thermal expansion coefficient(TEC)decreased from 34.1×10^(-6)(SrFeO_(3-δ))to 14.6×10^(-6) K^(-1)(STF),which is near the TEC of electrolyte(13.3×10^(-6) K^(-1) for Sm_(0.2)Ce_(0.8)O_(1.9),SDC),indicates excellent thermomechanical compatibility.At 550-750℃,STF shows superior oxygen vacancy concentrations(0.262 to 0.331),which is critical in the oxygen-reduction reaction(ORR).Oxygen temperature-programmed desorption(O_(2)-TPD)indicated the thermal reduction onset temperature of iron ion is around 420℃,which matched well with the inflection points on the thermos-gravimetric analysis and electrical conductivity curves.At 600℃,the STF electrode shows area-specific resistance(ASR)of 0.152Ω·cm^(2) and peak power density(PPD)of 749 mW·cm^(-2).ORR activity of STF was further improved by introducing 30wt%Sm_(0.2)Ce_(0.8)O_(1.9)(SDC)powder,STF+SDC composite cathode achieving outstanding ASR value of 0.115Ω·cm2 at 600℃,even comparable with benchmark cobalt-containing cathode,Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ)(BSCF).Distribution of relaxation time(DRT)analysis revealed that the oxygen surface exchange and bulk diffusion were improved by forming a composite cathode.At 650℃,STF+SDC composite cathode achieving an outstanding PPD of 1117 mW·cm^(-2).The excellent results suggest that STF and STF+SDC are promising air electrodes for IT-SOFCs.展开更多
The interconnect materials La0.7Ca0.3Cr1-xZnxO3-δ(x=0,0.01,0.03,0.05,0.07) were prepared by a microwave assisted sol-gel auto-ignition process.The crystalline structures of the samples were characterized by X-ray dif...The interconnect materials La0.7Ca0.3Cr1-xZnxO3-δ(x=0,0.01,0.03,0.05,0.07) were prepared by a microwave assisted sol-gel auto-ignition process.The crystalline structures of the samples were characterized by X-ray diffraction(XRD) and the lattice parameters were evaluated with Rietveld method.For Ca-Zn co-doped LaCrO3 with x=0.03,the sintering activity was improved,and the relative density came up to 96.5% for the sample sintered at 1300 oC for 10 h.The electrical conductivity of the samples was increased fr...展开更多
（Ba0.5Sr0.5）1-xPrxCo0.8Fe0.2O3-δ（BSPCFx;x=0.00-0.30） oxides were synthesized by a sol-gel thermolysis process using combination of PVA and urea,and were also investigated as cathode material for intermediate temp...（Ba0.5Sr0.5）1-xPrxCo0.8Fe0.2O3-δ（BSPCFx;x=0.00-0.30） oxides were synthesized by a sol-gel thermolysis process using combination of PVA and urea,and were also investigated as cathode material for intermediate temperature solid oxide fuel cells（IT-SOFCs）.X-ray diffraction（XRD） results showed that all the samples formed a single phase cubic pervoskite-type structure after being calcined at 950 oC for 5 h and the lattice constant decreased with the Pr content increasing.The electrical conductivity of Ba0.5Sr0.5Co0.8Fe0.2O3-δ（BSCF） was greatly enhanced by Pr-doping.The thermal expansion coefficient（TEC） of BSPCFx was increased with the content of Pr increasing,and all the thermal expansion curves had an inflection at about 250-400 oC due to the thermal-induced lattice oxygen loss and the reaction of Co and Fe ion.Ac impedance analysis indicated that BSPCFx possessed better electrochemical performance.The polarization resistance of the sample with x=0.2 was only ～0.948 Ω cm2 at 500 oC,significantly lower than that of BSCF（～2.488 Ω cm2）.展开更多
Herein,we report the synthesis of a Dy-Gd co-doped cubic phase-stabilized Bi_(2)O_(3) solid electrolyte system via solid-state processing under atmospheric conditions.Doping with Dy^(3+) and Gd^(3+) has been observed ...Herein,we report the synthesis of a Dy-Gd co-doped cubic phase-stabilized Bi_(2)O_(3) solid electrolyte system via solid-state processing under atmospheric conditions.Doping with Dy^(3+) and Gd^(3+) has been observed to significantly enhance the densification process during sintering for stabilization purposes,thereby improving the electrical properties of δ-Bi_(2)O_(3)-type polymorphs.The synthesized ceramics were characterized using X-ray diffraction(XRD),field emission scanning electron microscopy-energy dispersive X-ray spectroscopy(FESEM-EDX),thermal gravimetry/differential thermal analysis(TG/DTA),and the four-point probe technique(4PPT).XRD analysis reveals that the samples Bi_(1-x-y)Gd_(x)Dy_(y)O_(1.5)(y=0.05/x=0.05,0.10,0,15,and 0.20,and x=0.05/y=0.10,0.15,and 0.20) exhibit a stable face-centered cubic δ-phase and a mixed-phase crystallographic structure.The XRD analysis of the stabilized δ-phase suggests that the prepared oxides show a face-centered cubic(FCC) structure with a space group of Fm-3m.FESEM micrographs reveal that the composition Bi_(0.90)Gd_(0.05)Dy_(0.05)O_(1.5) has no significant holes.Nevertheless,an evident increase in the pore formation is observed as the amount of Gd_(2)O_(3) increases until it reaches 20%.This finding suggests that dense pellets are formed during the sintering process at 900-1000℃.The DTA analyses were performed to verify the phase stability,which agrees with the XRD results.The electrochemical performance of the synthesized Dy-Gd co-doped Bi_(2)O_(3)solid electrolyte system was evaluated and analyzed in detail by using the electrochemical impedance spectroscopy(EIS) technique,Based on EIS and conductivity measurements,Bi_(0.75)Gd_(0.20)Dy_(0.05)O_(1.5) exhibits the lowest activation energy of 0.519 eV and the highest conductivity value of 0.398 S/cm at 627℃compared to the other samples;this composition can be used as a solid electrolyte for intermediatetemperature solid oxide fuel cells(SOFCs).展开更多
The cathode material La1-xSrxCuO3-δ(x=0.15, 0.2, 0.3, 0.4) was synthesized by a sol-gel method. X-ray diffraction reveals that a single phase of perovskite is formed. The investigation of the electrical properties su...The cathode material La1-xSrxCuO3-δ(x=0.15, 0.2, 0.3, 0.4) was synthesized by a sol-gel method. X-ray diffraction reveals that a single phase of perovskite is formed. The investigation of the electrical properties suggests that La0.7Sr0.3CuO3-δ has the highest electrical conductivity. La0.7Sr0.3CuO3-δ powder was mixed with different amount SDC (Sm0.15Ce0.85O1.925) powder (5wt.%-30wt.%) as composite cathodes. Electrochemical properties of the composite cathodes were researched further. Investigation suggests that the addition of appropriate amount SDC to La0.7Sr0.3CuO3-δ can improve the electrochemical properties and obtain better cathodic performance. Using La0.7Sr0.3CuO3-δ-SDC composite materials as a cathode based on SDC electrolyte, higher current density and power density at intermediate temperatures can be obtained.展开更多
基金Project supported bythe National Natural Science Foundation of China (20271047)
文摘As a mixed ion-electronic conductor, doped ceria, especially rare earth doped ceria, were used as anodes or components of anodes in SOFCs. In this work, calcium doped ceria （CCO） was synthesized to be used in intermediate-temperature SOFCs （IT-SOFCs） anodes in order to reduce the cost of anode-supported SOFCs. Electrical conductivity of 20% calcium doped ceria （20CCO） reached 0.209 S·cm^-1 in hydrogen at 850 ℃, and 0.041 S·cm^-1 in air at 800℃, which is about 0.04 S·cm^-1 lower than that of conventional samaria-doped ceria （0.079 S·cm^-1）. Electrochemical performance of Ni-20CCO cermet as anode was investigated using a fuel cell with 35μm-thick SDC electrolyte and Sm0.5Sr0.5 Co-SDC cathode. Maximum power density was 623 mW·cm^-2 under humidified （3% H2O） hydrogen at 650 ℃, inferring high catalytic activity of the Ni-20CCO anode.
基金supported by the Guangdong Provincial Basic and Applied Basic Research Foundation(2021A1515010671,2020A1515011221)the Guangdong Provincial Key Discipline Research Capacity Enhancement Project(2021ZDJS071)the Guangdong Provincial College Innovation Project(2021KTSCX122,2022KQNCX077)。
文摘This study focuses on the impact of Gd^(3+),Sm^(3+),Er^(3+).Y^(3+),and Bi^(3+)multi-doping on the crystal structure,microscopic surface features,and ionic conductivity of cerium dioxide in the Ce_(1-x)(Gd_(1/5)Sm_(1/5)Er_(1/5)Y_(1/)_5Bi_(1/5))_(x)O_(2-δ)(GSEYB)system.This system holds promise as a solid electrolyte material for low and medium-temperature solid oxide fuel cells.The powders of Ce_(1-x)(Gd_(1/5)Sm_(1/5)Er_(1/5)Y_(1/5)Bi_(1/5))_(x)O_(2-δ)(x=0,0.10,0.15,0.20,0.25,0.30)were synthesized using the solid-phase reaction method.The GSEYB electrolytes were comprehensively investigated for their phase structure,microstructure,oxygen vacancy concentration,and ionic conductivity using X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),and impedance spectroscopy.XRD diffraction patterns confirm a cubic fluorite-type structure with Fm3m space groups in all multi-doped systems.After sintering at 1400℃for 10 h,the relative density of doped samples exceeds 96%.In terms of electrical properties,the Ce_(0.75)Gd_(0.05)Sm_(0.05)Er_(0.05)Y_(0.05)Bi_(0.05)O_(2-δ)(x=0.25)electrolyte exhibits the highest ionic conductivity(σ_(t)=4.45×10^(-2)S/cm)and the lowest activation energy(E_(a)=0.79 eV)at 800℃.The coefficient of thermal expansion of the developed electrolyte aligns well with that of the commonly used electrode materials.This compatibility positions it as a highly promising candidate for utilization as an electrolyte material in solid oxide fuel cells(SOFCs).
基金supported by JSPS KAKENHI Grant Number 22K04732,Japan.
文摘The development of cost-effective solid oxide fuel cells(SOFCs)is crucial for the large-scale application.In this study,anode-supported SOFC single cells were fabricated using a combination of slurry spraying and spin-coating technique to achieve a dense Yttria Stabilized Zirconia(YSZ)electrolyte layer while maintaining low production cost.The electrochemical performance of the fabricated SOFC was evaluated using hydrogen and dry methane as fuels.Microstructural analysis confirmed that the YSZ electrolyte exhibited high densification with a thickness of approximately 10μm,ensuring excellent gas-tightness and preventing fuel crossover.The NiO-YSZ anode demonstrated favorable porosity,with well-sintered NiO particles forming a robust framework to facilitate electrochemical reactions.Performance evaluations revealed that under hydrogen operation,the SOFC achieved a peak power density of 1.408 W/cm^(2)at 1000℃,with open-circuit voltages(OCVs)closely matching theoretical predictions.When operated with dry methane,the SOFC maintained stable performance,reaching a peak power density of 0.96 W/cm^(2)at 1000℃,highlighting its potential for direct hydrocarbon utilization.Gas composition analysis of the anode exhaust confirmed the absence of excessive carbon deposition,indicating the effectiveness of the anode microstructure in mitigating coking during methane oxidation.These findings demonstrate that the spray-coated and spin-coated SOFC design offers a promising approach to improving fuel cell efficiency and cost-effectiveness.Future research should focus on optimizing electrolyte fabrication methods and enhancing anode stability in hydrocarbon-fueled operation to further advance the commercialization of SOFC technology.
基金Project supported by Eskom-Tertiary Education Support Programthe National Research Foundation of South Africa(Thuthuka Program,76318)
文摘A sol-gel method and a modified chemical vapour deposition technique were used to produce nanostructured Ce0.6Sr0.4Fe0.8Co0.2O3-δ materials at temperatures as low as 400 ℃. Powders were characterized using Fourier transform infrared spectroscopy （FTIR）, Raman spectroscopy, thermo gravimetric analysis, powder X-ray diffraction （XRD）, scanning electron microscopy （SEM） with energy dispersive X-ray spectroscopy, high resolution transmission electron microscopy （HRTEM）, and nitrogen sorption at 77 K. FTIR spectra showed that the sol-gel method resulted in residual carbon groups on the materials after calcination, while the Raman and XRD analysis confirmed that both synthesis methods resulted in cubic perovskite structure. However, the chemical va- pour deposition （CVD） method resulted in materials with a smaller crystallite size when compared to those prepared via the sol-gel route. The overall morphology of the powders was irregularly shaped aggregated particles as observed by SEM and HRTEM. In addition, HRTEM analysis showed that the materials were highly crystalline. Textural analysis revealed the powders had some mesoporosity, and the surface areas were 76.69 and 65.90 m2/g for materials synthesized using the CVD and sol-gel methods, respectively. The synthesized perovskite powders were used to fabricate button cells employing samarium doped ceria （SDC） as the electrolyte and NiO/SDC as the anode materials. As cathode materials, the maximum power density observed was 308.4 mW/cm2 at 500℃.
基金financially supported by the National Natural Science Foundation of China(Nos.51401028,51271193,11402277,11790292)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB22040303)the Innovation Program(No.237099000000170004)。
文摘High-entropy alloys(HEAs)have attracted tremendous attention owing to their controllable mechanical properties,whereas additive manufacturing(AM)is an efficient and flexible processing route for novel materials design.However,a profound appraisal of the fundamental material physics behind the strengthening of AM-printed HEAs upon low/intermediate-temperature annealing is essential.In this work,Co CrFe Ni Mn HEAs have been prepared using laser-engineered net shaping(LENS)and subsequently annealed at different temperatures.The Co Cr Fe Ni Mn HEA annealed at intermediate-temperature(873 K)exhibits a strong strain hardening capability,resulting in ultimate strength of 725 MPa and plasticity of 22%.A ternary heterogeneous strengthening mechanism is proposed to explain this phenomenon,in which equiaxed grains,columnar grains,andσprecipitates play different roles during tensile deformation.The resultant excellent strength and ductility can be ascribed to the heterostructure-induced mismatch.The equiaxed grains provide adequate grain boundaries(GBs),which induce dislocation plugging-up and entanglement;the columnar grains induce the onset and arrest of the dislocations for plastic deformation;and theσprecipitates hinder the movement of slip dislocations.The results provide new insights into overcoming the strength-ductility trade-off of LENS-printed HEAs with complex geometries.
文摘New cobalt-free composites consisting of Ba0.5Sr0.5Fe0.9Ni0.1O3-δ （BSFN） and Ce0.8Sm0.2O2-δ （SDC） were investigated as possible cathode materials for intermediate-temperature solid oxide fuel cell （IT-SOFC）. BSFN, which was synthesized by auto ignition process, was chemically compatible with SDC up to 1100 ℃ as indicated by X-ray diffraction analysis. The electrical conductivity of BSFN reached the maximum value of 57 S.cm-1 at 450 ℃. The thermal expansion coefficient （TEC） value of BSFN was 30.9×10-6 K-1, much higher than that of typical electrolytes. The electrochemical behavior of the composites was analyzed via electrochemical impedance spectroscopy with symmetrical cells BSFN-SDC/SDC/BSFN-SDC. The area specific interracial polarization resistance （ASR） decreased with increasing SDC content of the composite. The area specific interracial polarization resistance （ASR） at 700 ℃ is only 0.49, 0.34 and 0.31 Ω.cm2 when 30, 40, and 50 wt% SDC was cooperated to BSFN, respectively. These results suggest that BSFN-SDC is a possible candidate for IT-SOFC cathode.
文摘A new cathode material fabricated by solid state reaction method was reported. The SmVO4 powder was obtained by firing the mixture of Sm2O3 and V2O5 powders in the temperature range of 700-1200 ℃. Its structure was identified by X-ray diffraction method and the electrochemical properties of SmVO4 as cathodes for solid oxide fuel cells (SOFCs) were investigated in single unit cell at the temperature ranged from 450-550 ℃. The results of the single fuel cell unit show that the maximum current densities are 641, 797, 688 mA·cm-2 and the maximum power output are 165, 268, 303 mW·cm-2 and the open circuit voltage are 1.04, 0.96, 0.92 V at 450, 500 and 550 ℃, respectively.
基金funded by the National Key R&D Program of China(2022YFB4101702)the National Natural Science Foundation of China(52106072 and 52225003)the Fundamental Research Funds for Central Universities(2019JQ03015)。
文摘Carbon capture,utilization and storage(CCUS) is widely recognized as a vital strategy for mitigating the impact of human induced climate change.Among various CO_(2) adsorbents,intermediate-temperature solid adsorbents have garnered significant attention due to their potential applications in hydrogen utilization,specifically in the water gas shift,steam reforming and gasification processes.These processes are crucial for achieving carbon neutrality.While laboratory-level studies have showcased the high adsorption capacity of these materials via various synthesis and modification methods,their practical application in complex industrial environments remains challenging,impeding the commercialization process.This review aims to critically summarize the recent research progress made in intermediatetemperature(200-400℃) solid CO_(2) adsorbents,particularly focusing on indicators such as cyclability,gas selectivity,and formability,which play vital roles in industrial application scenarios.Additionally,we provide an overview of laboratory-level advanced technologies specifically tailored for industrial applications.Furthermore,we highlight several industrial-ready advanced technologies that can pave the way for overcoming the challenges associated with large-scale implementation.The insights provided by this review aim to assist researchers in identifying the most relevant research directions for industrial applications.By promoting advances in the application of solid adsorbents,we strive to facilitate the ultimate goal of achieving carbon neutrality.
基金financially supported by the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.2018ND133J)the National Natural Science Foundation of China(Nos.22309067 and 22101150)the Natural Science Foundation of Jiangsu Province,China(No.BK20190965).
文摘To explore highly active and thermomechanical stable air electrodes for intermediate-temperature solid oxide fuel cells(ITSOFCs),10mol%Ta5+doped in the B site of strontium ferrite perovskite oxide(SrTa_(0.1)Fe_(0.9)O_(3-δ),STF)is investigated and optimized.The effects of Ta^(5+)doping on structure,transition metal reduction,oxygen nonstoichiometry,thermal expansion,and electrical performance are evaluated systematically.Via 10mol%Ta^(5+)doping,the thermal expansion coefficient(TEC)decreased from 34.1×10^(-6)(SrFeO_(3-δ))to 14.6×10^(-6) K^(-1)(STF),which is near the TEC of electrolyte(13.3×10^(-6) K^(-1) for Sm_(0.2)Ce_(0.8)O_(1.9),SDC),indicates excellent thermomechanical compatibility.At 550-750℃,STF shows superior oxygen vacancy concentrations(0.262 to 0.331),which is critical in the oxygen-reduction reaction(ORR).Oxygen temperature-programmed desorption(O_(2)-TPD)indicated the thermal reduction onset temperature of iron ion is around 420℃,which matched well with the inflection points on the thermos-gravimetric analysis and electrical conductivity curves.At 600℃,the STF electrode shows area-specific resistance(ASR)of 0.152Ω·cm^(2) and peak power density(PPD)of 749 mW·cm^(-2).ORR activity of STF was further improved by introducing 30wt%Sm_(0.2)Ce_(0.8)O_(1.9)(SDC)powder,STF+SDC composite cathode achieving outstanding ASR value of 0.115Ω·cm2 at 600℃,even comparable with benchmark cobalt-containing cathode,Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ)(BSCF).Distribution of relaxation time(DRT)analysis revealed that the oxygen surface exchange and bulk diffusion were improved by forming a composite cathode.At 650℃,STF+SDC composite cathode achieving an outstanding PPD of 1117 mW·cm^(-2).The excellent results suggest that STF and STF+SDC are promising air electrodes for IT-SOFCs.
基金supported by the Key Fund of Natural Science for Education Department of Anhui Province,China (KJ2008A150)
文摘The interconnect materials La0.7Ca0.3Cr1-xZnxO3-δ(x=0,0.01,0.03,0.05,0.07) were prepared by a microwave assisted sol-gel auto-ignition process.The crystalline structures of the samples were characterized by X-ray diffraction(XRD) and the lattice parameters were evaluated with Rietveld method.For Ca-Zn co-doped LaCrO3 with x=0.03,the sintering activity was improved,and the relative density came up to 96.5% for the sample sintered at 1300 oC for 10 h.The electrical conductivity of the samples was increased fr...
基金Project supported by Key Natrual Science Foundation of Education Department of Inner Mongolia(NJZZ11013)China Postdoctoral Science Foundation,and Higher-level Talents of Inner Mongolia University (Z20090105)
文摘（Ba0.5Sr0.5）1-xPrxCo0.8Fe0.2O3-δ（BSPCFx;x=0.00-0.30） oxides were synthesized by a sol-gel thermolysis process using combination of PVA and urea,and were also investigated as cathode material for intermediate temperature solid oxide fuel cells（IT-SOFCs）.X-ray diffraction（XRD） results showed that all the samples formed a single phase cubic pervoskite-type structure after being calcined at 950 oC for 5 h and the lattice constant decreased with the Pr content increasing.The electrical conductivity of Ba0.5Sr0.5Co0.8Fe0.2O3-δ（BSCF） was greatly enhanced by Pr-doping.The thermal expansion coefficient（TEC） of BSPCFx was increased with the content of Pr increasing,and all the thermal expansion curves had an inflection at about 250-400 oC due to the thermal-induced lattice oxygen loss and the reaction of Co and Fe ion.Ac impedance analysis indicated that BSPCFx possessed better electrochemical performance.The polarization resistance of the sample with x=0.2 was only ～0.948 Ω cm2 at 500 oC,significantly lower than that of BSCF（～2.488 Ω cm2）.
文摘Herein,we report the synthesis of a Dy-Gd co-doped cubic phase-stabilized Bi_(2)O_(3) solid electrolyte system via solid-state processing under atmospheric conditions.Doping with Dy^(3+) and Gd^(3+) has been observed to significantly enhance the densification process during sintering for stabilization purposes,thereby improving the electrical properties of δ-Bi_(2)O_(3)-type polymorphs.The synthesized ceramics were characterized using X-ray diffraction(XRD),field emission scanning electron microscopy-energy dispersive X-ray spectroscopy(FESEM-EDX),thermal gravimetry/differential thermal analysis(TG/DTA),and the four-point probe technique(4PPT).XRD analysis reveals that the samples Bi_(1-x-y)Gd_(x)Dy_(y)O_(1.5)(y=0.05/x=0.05,0.10,0,15,and 0.20,and x=0.05/y=0.10,0.15,and 0.20) exhibit a stable face-centered cubic δ-phase and a mixed-phase crystallographic structure.The XRD analysis of the stabilized δ-phase suggests that the prepared oxides show a face-centered cubic(FCC) structure with a space group of Fm-3m.FESEM micrographs reveal that the composition Bi_(0.90)Gd_(0.05)Dy_(0.05)O_(1.5) has no significant holes.Nevertheless,an evident increase in the pore formation is observed as the amount of Gd_(2)O_(3) increases until it reaches 20%.This finding suggests that dense pellets are formed during the sintering process at 900-1000℃.The DTA analyses were performed to verify the phase stability,which agrees with the XRD results.The electrochemical performance of the synthesized Dy-Gd co-doped Bi_(2)O_(3)solid electrolyte system was evaluated and analyzed in detail by using the electrochemical impedance spectroscopy(EIS) technique,Based on EIS and conductivity measurements,Bi_(0.75)Gd_(0.20)Dy_(0.05)O_(1.5) exhibits the lowest activation energy of 0.519 eV and the highest conductivity value of 0.398 S/cm at 627℃compared to the other samples;this composition can be used as a solid electrolyte for intermediatetemperature solid oxide fuel cells(SOFCs).
文摘The cathode material La1-xSrxCuO3-δ(x=0.15, 0.2, 0.3, 0.4) was synthesized by a sol-gel method. X-ray diffraction reveals that a single phase of perovskite is formed. The investigation of the electrical properties suggests that La0.7Sr0.3CuO3-δ has the highest electrical conductivity. La0.7Sr0.3CuO3-δ powder was mixed with different amount SDC (Sm0.15Ce0.85O1.925) powder (5wt.%-30wt.%) as composite cathodes. Electrochemical properties of the composite cathodes were researched further. Investigation suggests that the addition of appropriate amount SDC to La0.7Sr0.3CuO3-δ can improve the electrochemical properties and obtain better cathodic performance. Using La0.7Sr0.3CuO3-δ-SDC composite materials as a cathode based on SDC electrolyte, higher current density and power density at intermediate temperatures can be obtained.
