PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula...PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.展开更多
Ethylene,one of the most widely produced building blocks in the petrochemical industry,has received intense attention.Ethylene production,using electrochemical hydrogen pump-facilitated nonoxidative dehydrogenation of...Ethylene,one of the most widely produced building blocks in the petrochemical industry,has received intense attention.Ethylene production,using electrochemical hydrogen pump-facilitated nonoxidative dehydrogenation of ethane(NDE)to ethylene,is an emerging and promising route,promoting the transformation of the ethylene industry from energy-intensive steam cracking process to new electrochemical membrane reactor technology.In this work,the NDE reaction is incorporated into a BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)electrolyte-supported protonic ceramic fuel cell membrane reactor to co-generate electricity and ethylene,utilizing the Nb and Cu doped perovskite oxide Pr_(0.6)Sr_(0.4)Fe_(0.8)Nb_(0.1)Cu_(0.1)O_(3-δ)(PSFNCu)as anode catalytic layer.Due to the doping of Nb and Cu,PSFNCu was endowed with high reduction tolerance and rich oxygen vacancies,showing excellent NDE catalytic performance.The maximum power density of the assembled reactor reaches 200 mW cm^(-2)at 750℃,with high ethane conversion(44.9%)and ethylene selectivity(92.7%).Moreover,the nitrous oxide decomposition was first coupled in the protonic ceramic fuel cell membrane reactor to consume the permeated protons.As a result,the generation of electricity,ethylene and decomposition of nitrous oxide can be simultaneously obtained by a single reactor.Specifically,the maximum power density of the cell reaches 208 mW cm^(-2)at 750℃,with high ethane conversion(45.2%),ethylene selectivity(92.5%),and nitrous oxide conversion(19,0%).This multi-win technology is promising for not only the production of chemicals and energy but also greenhouse gas reduction.展开更多
Protonic ceramic fuel cells(PCFCs)are more suitable for operation at low temperatures due to their smaller activation energy(Ea).Unfortunately,the utilization of PCFC technology at reduced temperatures is limited by t...Protonic ceramic fuel cells(PCFCs)are more suitable for operation at low temperatures due to their smaller activation energy(Ea).Unfortunately,the utilization of PCFC technology at reduced temperatures is limited by the lack of durable and high-activity air electrodes.A lot number of cobalt-based oxides have been developed as air electrodes for PCFCs,due to their high oxygen reduction reaction(ORR)activity.However,cobalt-based oxides usually have more significant thermal expansion coefficients(TECs)and poor thermomechanical compatibility with electrolytes.These characteristics can lead to cell delamination and degradation.Herein,we rationally design a novel cobalt-containing composite cathode material with the nominal composition of Sr_(4)Fe_(4)Co_(2)O_(13)+δ(SFC).SFC is composed of tetragonal perovskite phase(Sr_(8)Fe_(8)O_(23)+δ,I4/mmm,81 wt.%)and spinel phase(Co_(3)O_(4),Fd3m,19 wt.%).The SFC composite cathode displays an ultra-high oxygen ionic conductivity(0.053 S·cm^(-1)at 550℃),superior CO_(2)tolerance,and suitable TEC value(17.01×10^(-6)K^(-1)).SFC has both the O_(2)^(-)/e^(-)conduction function,and the triple conducting(H^(+)/O_(2)^(-)/e^(-))capability was achieved by introducing the protonic conduction phase(BaZr_(0.2)Ce_(0.7)Y_(0.1)O_(3-δ),BZCY)to form SFC+BZCY(70 wt.%:30 wt.%).The SFC+BZCY composite electrode exhibits superior ORR activity at a reduced temperature with extremely low area-specific resistance(ASR,0.677Ω·cm^(2)at 550℃),profound peak power density(PPD,535 mW·cm^(-2)and 1.065 V at 550℃),extraordinarily long-term durability(>500 h for symmetrical cell and 350 h for single cell).Moreover,the composite has an ultra-low TEC value(15.96×10^(-6)K^(-1)).This study proves that SFC+BZCY with triple conducting capacity is an excellent cathode for low-temperature PCFCs.展开更多
Protonic ceramic fuel cells(PCFCs)have been attracting increasing attention because of their advances in high-efficiency power generation in an intermediate-temperature range,as compared to the high-temperature solid ...Protonic ceramic fuel cells(PCFCs)have been attracting increasing attention because of their advances in high-efficiency power generation in an intermediate-temperature range,as compared to the high-temperature solid oxide fuel cells(SOFCs).The greatest difference between PCFCs and SOFCs is the specific requirement of protonic(H+)conductivity at the PCFC cathode,in addition to the electronic(e^(-))and oxide-ion(O^(2-))conductivity.The development of a triple H^(+)/e^(-)/O^(2-)conductor for PCFC cathode is still challenging.Thus,the most-widely used cathode material is based on the mature e^(-)/O^(2-)conductor.However,this leads to insufficient triple phase boundary(TPB),i.e.,reaction area.Herein,an efficient strategy that uses a~100 nm-thick proton conductive functional layer(La_(0.5)Sr_(0.5)CoO_(3-δ),LSC55)in-between the typical La_(0.8)Sr_(0.2)CoO_(3-δ)cathode(a mature e-/O^(2-)conductor,LS C 82)and B aZr_(0.4)Ce_(0.4)Y_(0.1)Yb_(0.)1O_(3-δ)elec trolyte(11 mm in diameter,20μm in thickness)is proposed to significantly enhance the reaction area.Reasonably,the ohmic resistance and polarization resistance are both decreased by 47%and 62%,respectively,compared with that of PCFCs without the functional layer.The power density of the PCFC with such a functional layer can be raised by up to 2.24 times,superior to those described in previous reports.The enhanced PCFC performances are attributed to the well-built TPB and enhanced reaction area via the functional layer engineering strategy.展开更多
The performance degradation mechanism of ceramic fuel cell with NCAL(Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2))as symmetrical electrode and GDC as electrolyte in H2 is investigated.It is found that under the condition of 550◦...The performance degradation mechanism of ceramic fuel cell with NCAL(Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2))as symmetrical electrode and GDC as electrolyte in H2 is investigated.It is found that under the condition of 550◦C and constant current density of 0.2 A⋅cm^(-2),the output voltage of the cell is about 1.005 V in the initial 10 h and remains relatively stable.After 10 h,the voltage of the cell began to decrease gradually,and by 50 h,the voltage had decreased to 0.522 V.The results testing electrochemical performance of the cell and characterizing the cell materials before and after test using SEM,TOF-SIMS and FTIR indicate that the distribution of Li_(2)O/LiOH/Li_(2)CO_(3)compounds generated from NCAL anode in the cell plays a vital role in significantly improving the ionic conductivity of electrolyte and gas tightness of the cell.The dynamic migration of molten salt destroyed the continuity of molten salt in the cell,which in turn adversely impacted the ionic conductivity of electrolyte,gas tightness of the cell,and electrochemical reactions on both sides of the cathode and anode.These finally lead to the degradation of the cell performance.展开更多
Protonic ceramic fuel cells(PCFCs)offer a convenient means for electrochemical conversion of chemical energy into electricity at intermediate temperatures with very high efficiency.Although BaCeO_(3)-and BaZrO_(3)-bas...Protonic ceramic fuel cells(PCFCs)offer a convenient means for electrochemical conversion of chemical energy into electricity at intermediate temperatures with very high efficiency.Although BaCeO_(3)-and BaZrO_(3)-based complex oxides have been positioned as the most promising PCFC electrolytes,the design of new protonic conductors with improved properties is of paramount importance.Within the present work,we studied transport properties of scandium-doped barium stannate(Sc-doped BaSnO_(3)).Our analysis included the fabrication of porous and dense BaSn_(1−x)Sc_(x)O_(3−δ)ceramic materials(0≤x≤0.37),as well as a comprehensive analysis of their total,ionic,and electronic conductivities across all the experimental conditions realized under the PCFC operation:both air and hydrogen atmospheres with various water vapor partial pressures(p(H2O)),and a temperature range of 500–900℃.This work reports on electrolyte domain boundaries of the undoped and doped BaSnO_(3)for the first time,revealing that pure BaSnO_(3)exhibits mixed ionic–electronic conduction behavior under both oxidizing and reducing conditions,while the Sc-doping results in the gradual improvement of ionic(including protonic)conductivity,extending the electrolyte domain boundaries towards reduced atmospheres.This latter property makes the heavilydoped BaSnO_(3)representatives attractive for PCFC applications.展开更多
Slow oxygen reduction reaction(ORR)involving proton transport remains the limiting factor for electrochemical performance of proton-conducting cathodes.To further reduce the operating temperature of protonic ceramic f...Slow oxygen reduction reaction(ORR)involving proton transport remains the limiting factor for electrochemical performance of proton-conducting cathodes.To further reduce the operating temperature of protonic ceramic fuel cells(PCFCs),developing triple-conducting cathodes with excellent electrochemical performance is required.In this study,K-doped BaCo_(0.4)Fe_(0.4)Zr_(0.2)O_(3−δ)(BCFZ442)series were developed and used as the cathodes of the PCFCs,and their crystal structure,conductivity,hydration capability,and electrochemical performance were characterized in detail.Among them,Ba_(0.9)K_(0.1)Co_(0.4)Fe_(0.4)Zr_(0.2)O_(3−δ)(K10)cathode has the best electrochemical performance,which can be attributed to its high electron(e^(−))/oxygen ion(O^(2−))/H^(+)conductivity and proton uptake capacity.At 750℃,the polarization resistance of the K10 cathode is only 0.009Ω·cm^(2),the peak power density(PPD)of the single cell with the K10 cathode is close to 1 W·cm^(−2),and there is no significant degradation within 150 h.Excellent electrochemical performance and durability make K10 a promising cathode material for the PCFCs.This work can provide a guidance for further improving the proton transport capability of the triple-conducting oxides,which is of great significance for developing the PCFC cathodes with excellent electrochemical performance.展开更多
Previous studies have found that the ceramic fuel cell using Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2)(NCAL)symmetrical electrode has obtained very good power generation performance in the temperature range of 450 to 550℃.Pr...Previous studies have found that the ceramic fuel cell using Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2)(NCAL)symmetrical electrode has obtained very good power generation performance in the temperature range of 450 to 550℃.Previous studies have pointed out that after being reduced by H2,NCAL anode will produce LiOH/Li2CO3 mixture and diffuse into the electrolyte,which results in the high ionic conductivity of the cell.In this study,the chemical reactivity of different oxide electrolytes such as CeO_(2),TiO_(2),ZrO_(2)and YSZ with LiOH and/or Li2CO3 and their effects on the electrochemical performance of the cell were studied.It is found that at 550◦C,only the open circuit voltage(OCV)of the cell using CeO_(2)as electrolyte can remain stable,and the maximum power density(MPD)of the CeO_(2)electrolyte cell reaches 599.6 mW⋅cm^(−2).The OCV of the cells with TiO_(2),ZrO_(2)and YSZ as electrolyte increased to the highest value within a few minutes,and the MPD of the cells was only more than 12 mW⋅cm^(−2).XRD,FT-IR,SEM-EDS and ICP-OES results indicate that the LiOH/Li2CO3 mixture diffuses into TiO_(2),ZrO_(2)and YSZ electrolytes and reacts with three oxides to produce Li2TiO3 and Li2ZrO3,respectively,which results in the low performance of the cell.展开更多
A deep-learning-based framework is proposed to predict the impedance response and underlying electrochemical behavior of the reversible protonic ceramic cell(PCC) across a wide variety of different operating condition...A deep-learning-based framework is proposed to predict the impedance response and underlying electrochemical behavior of the reversible protonic ceramic cell(PCC) across a wide variety of different operating conditions.Electrochemical impedance spectra(EIS) of PCCs were first acquired under a variety of opera ting conditions to provide a dataset containing 36 sets of EIS spectra for the model.An artificial neural network(ANN) was then trained to model the relationship between the cell operating condition and EIS response.Finally,ANN model-predicted EIS spectra were analyzed by the distribution of relaxation times(DRT) and compared to DRT spectra obtained from the experimental EIS data,enabling an assessment of the accumulative errors from the predicted EIS data vs the predicted DRT.We show that in certain cases,although the R^(2)of the predicted EIS curve may be> 0.98,the R^(2)of the predicted DRT may be as low as~0.3.This can lead to an inaccurate ANN prediction of the underlying time-resolved electrochemical response,although the apparent accuracy as evaluated from the EIS prediction may seem acceptable.After adjustment of the parameters of the ANN framework,the average R^(2)of the DRTs derived from the predicted EIS can be improved to 0.9667.Thus,we demonstrate that a properly tuned ANN model can be used as an effective tool to predict not only the EIS,but also the DRT of complex electrochemical systems.展开更多
Solid oxide fuel cells(SOFCs)and electrolysis cells(SOECs)are promising energy conversion devices,on whose basis green hydrogen energy technologies can be developed to support the transition to a carbon-free future.As...Solid oxide fuel cells(SOFCs)and electrolysis cells(SOECs)are promising energy conversion devices,on whose basis green hydrogen energy technologies can be developed to support the transition to a carbon-free future.As compared with oxygen-conducting cells,the operational temperatures of protonic ceramic fuel cells(PCFCs)and electrolysis cells(PCECs)can be reduced by several hundreds of degrees(down to low-and intermediatetemperature ranges of 400–700C)while maintaining high performance and efficiency.This is due to the distinctive characteristics of charge carriers for proton-conducting electrolytes.However,despite achieving outstanding lab-scale performance,the prospects for industrial scaling of PCFCs and PCECs remain hazy,at least in the near future,in contrast to commercially available SOFCs and SOECs.In this review,we reveal the reasons for the delayed technological development,which need to be addressed in order to transfer fundamental findings into industrial processes.Possible solutions to the identified problems are also highlighted.展开更多
In recent years, interest in hydrogen as a fuel has sharply increased in the field of alternative and green energy due to its high energy capability and zero-emission behaviour. As a result, research in the developmen...In recent years, interest in hydrogen as a fuel has sharply increased in the field of alternative and green energy due to its high energy capability and zero-emission behaviour. As a result, research in the development of new highly efficient methods for producing high-purity hydrogen is relevant. This paper presents, for the first time, the test results of an electrochemical cell with a proton-conducting La_(0.9)Sr_(0.1)ScO_(3-δ) electrolyte and symmetrical Sr_(1.95)Fe_(1.4)Ni_(0.1)Mo_(0.5)O_(6-δ)+ La_(0.9)Sr_(0.1)Sc_(0.9)Co_(0.1)O_(3-δ) electrodes as a hybrid setup for electricity generation in proton ceramic fuel cell mode, for hydrogen separation from H_(2)+ Ar mixture and the production of high-purity hydrogen from methane with simultaneous CO_(2) utilization.It was found that this electrochemical cell generates high flow rates of hydrogen during its separation through a proton-conducting membrane from H_(2)+ Ar mixture, about 500 cm^(3)h^(-1)cm^(-2)at a current density of 0.6 A cm^(-2)as well as about 370 cm^(3) h^(-1)cm^(-2)at a current density of 0.5 A cm^(-2) from CH_(4)+ CO_(2) mixture at 800 ℃ which shows that these cells are promising for hydrogen production.展开更多
The development of proton,oxygen-ion,and electron mixed conducting materials,known as triple-conduction materials,as cathodes for proton-conducting solid oxide fuel cells(H-SOFCs)is highly desired because they can inc...The development of proton,oxygen-ion,and electron mixed conducting materials,known as triple-conduction materials,as cathodes for proton-conducting solid oxide fuel cells(H-SOFCs)is highly desired because they can increase fuel cell performance by extending the reaction active area.Although oxygen-ion and electron conductions can be measured directly,proton conduction in these oxides is usually estimated indirectly.Because of the instability of cathode materials in a reducing environment,direct measurement of proton conduction in cathode oxide is difficult.The La0.8Sr0.2Sc0.5Fe0.5O3–δ(LSSF)cathode material is proposed for H-SOFCs in this study,which can survive in an H_(2)-containing atmosphere,allowing measurement of proton conduction in LSSF by hydrogen permeation technology.Furthermore,LSSF is discovered to be a unique proton and electron mixed-conductive material with limited oxygen diffusion capability that is specifically designed for H-SOFCs.The LSSF is an appealing cathode choice for H-SOFCs due to its outstanding CO_(2)tolerance and matched thermal expansion coefficient,producing a record-high performance of 2032 mW cm^(−2)at 700℃and good long-term stability under operational conditions.The current study reveals that a new type of proton–electron mixed conducting cathode can provide promising performance for H-SOFCs,opening the way for developing high-performance cathodes.展开更多
New two-layer Ruddlesden-Popper(RP)oxide La_(0.25)Sr_(2.75)FeNiO_(7-δ)(LSFN)in the combination of Sr_(3)Fe_(2)O_(7-δ) and La_(3)Ni_(2)O_(7-δ) was successfully synthesized and studied as the potential active single-...New two-layer Ruddlesden-Popper(RP)oxide La_(0.25)Sr_(2.75)FeNiO_(7-δ)(LSFN)in the combination of Sr_(3)Fe_(2)O_(7-δ) and La_(3)Ni_(2)O_(7-δ) was successfully synthesized and studied as the potential active single-phase and composite cathode for protonic ceramics fuel cells(PCFCs).LSFN with the tetragonal symmetrical structure(IMmmm)is confinned,and the co-existence of Fe^(3+)/Fe^(4+) and Ni^(3+)/Ni^(2+) couples is demonstrated by X-ray photoelectron spectrometer(XPS)analysis.The LSFN conductivity is apparently enhanced after Ni doping in Fe-site,and nearly three times those of Sr_(3)Fe_(2)O_(7-δ),which is directly related to the carrier concentration and conductor mechanism.Importantly,anode supported PCFCs using LSFN-BaZr_(0.1)Ce_(0.7)Y_(0.2)O_(3-δ)(LSFN-BZCY)composite cathode achieved high power density(426 mW·cm^(-2) at 650℃)and low electrode interface polarization resistance(0.26Ω·cm^(2)).Besides,distribution of relaxation time(DRT)function technology was further used to analyse the electrode polarization processes.The observed three peaks(Pl,P2,and P3)separated by DRT shifted to the high frequency region with the decreasing temperature,suggesting that the charge transfer at the electrode-electrolyte interfaces becomes more difficult at reduced temperatures.Preliminary results demonstrate that new two-layer RP phase LSFN can be a promising cathode candidate for PCFCs.展开更多
One of the critical challenges for the protonic ceramic fuel cell stack is sealing electrolytes and interconnects.However,the traditional AgeCuO sealant will aggravate the oxidation along the interconnect surface and ...One of the critical challenges for the protonic ceramic fuel cell stack is sealing electrolytes and interconnects.However,the traditional AgeCuO sealant will aggravate the oxidation along the interconnect surface and result in brittle compound layers at the BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)(BZCYYb)electrolyte interface.The present work demonstrates that a silver particle interlayer with high dislocation density can be adopted to join BZCYYb electrolyte to the interconnect(AISI 441 stainless)in air instead of traditional AgeCuO sealant.Elevating temperatures result in a sufficient bonding at the Ag/BZCYYb interface,and a defect-free joint is obtained at 950℃.Atomic bonding at Ag/BZCYYb interface is confirmed by TEM.Also,a dense and thin oxide layer(2-3 μm)is formed along the AISI 441 interface.Ag particles in the interlayer provide the main driving force for the sintering joining.The massive dislocations promote the recovery and recrystallization of the Ag interlayer,as well as the interdiffusion of BZCYYb/Ag.After aging in the wet oxidizing atmosphere at 600℃ for 300 h,joints remain intact and dense,indicating superior oxidation resistance and aging performance.Besides,the joint shear strength(25.3 MPa)is 59%higher than that of the joint brazed by traditional AgeCuO.展开更多
基金supported by the National Research Foundation (NRF) grant funded by the Korea government (NRF2022R1C1C1007619, NRF-2021M3H4A1A01002921, NRF2021M3I3A1084292)supported by the KIST Institutional Program (Project No. 2E32592-23-069)。
文摘PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.
基金funding from the National Key R&D Program of China(2020YFB1505603)the Natural Science Foundation of China(22075086,22138005,22141001)the Guangdong Basic and Applied Basic Research Foundation(2019A1515011512,2020A1515011157,2021A1515010172,2022A1515010980)。
文摘Ethylene,one of the most widely produced building blocks in the petrochemical industry,has received intense attention.Ethylene production,using electrochemical hydrogen pump-facilitated nonoxidative dehydrogenation of ethane(NDE)to ethylene,is an emerging and promising route,promoting the transformation of the ethylene industry from energy-intensive steam cracking process to new electrochemical membrane reactor technology.In this work,the NDE reaction is incorporated into a BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)electrolyte-supported protonic ceramic fuel cell membrane reactor to co-generate electricity and ethylene,utilizing the Nb and Cu doped perovskite oxide Pr_(0.6)Sr_(0.4)Fe_(0.8)Nb_(0.1)Cu_(0.1)O_(3-δ)(PSFNCu)as anode catalytic layer.Due to the doping of Nb and Cu,PSFNCu was endowed with high reduction tolerance and rich oxygen vacancies,showing excellent NDE catalytic performance.The maximum power density of the assembled reactor reaches 200 mW cm^(-2)at 750℃,with high ethane conversion(44.9%)and ethylene selectivity(92.7%).Moreover,the nitrous oxide decomposition was first coupled in the protonic ceramic fuel cell membrane reactor to consume the permeated protons.As a result,the generation of electricity,ethylene and decomposition of nitrous oxide can be simultaneously obtained by a single reactor.Specifically,the maximum power density of the cell reaches 208 mW cm^(-2)at 750℃,with high ethane conversion(45.2%),ethylene selectivity(92.5%),and nitrous oxide conversion(19,0%).This multi-win technology is promising for not only the production of chemicals and energy but also greenhouse gas reduction.
基金This research was financially supported by the National Natural Science Foundation of China(No.22179054)the National Natural Science Foundation of China(No.22101150)+1 种基金Natural Science Foundation of Jiangsu Province,China(No.BK20190965)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.18KJB470011).
文摘Protonic ceramic fuel cells(PCFCs)are more suitable for operation at low temperatures due to their smaller activation energy(Ea).Unfortunately,the utilization of PCFC technology at reduced temperatures is limited by the lack of durable and high-activity air electrodes.A lot number of cobalt-based oxides have been developed as air electrodes for PCFCs,due to their high oxygen reduction reaction(ORR)activity.However,cobalt-based oxides usually have more significant thermal expansion coefficients(TECs)and poor thermomechanical compatibility with electrolytes.These characteristics can lead to cell delamination and degradation.Herein,we rationally design a novel cobalt-containing composite cathode material with the nominal composition of Sr_(4)Fe_(4)Co_(2)O_(13)+δ(SFC).SFC is composed of tetragonal perovskite phase(Sr_(8)Fe_(8)O_(23)+δ,I4/mmm,81 wt.%)and spinel phase(Co_(3)O_(4),Fd3m,19 wt.%).The SFC composite cathode displays an ultra-high oxygen ionic conductivity(0.053 S·cm^(-1)at 550℃),superior CO_(2)tolerance,and suitable TEC value(17.01×10^(-6)K^(-1)).SFC has both the O_(2)^(-)/e^(-)conduction function,and the triple conducting(H^(+)/O_(2)^(-)/e^(-))capability was achieved by introducing the protonic conduction phase(BaZr_(0.2)Ce_(0.7)Y_(0.1)O_(3-δ),BZCY)to form SFC+BZCY(70 wt.%:30 wt.%).The SFC+BZCY composite electrode exhibits superior ORR activity at a reduced temperature with extremely low area-specific resistance(ASR,0.677Ω·cm^(2)at 550℃),profound peak power density(PPD,535 mW·cm^(-2)and 1.065 V at 550℃),extraordinarily long-term durability(>500 h for symmetrical cell and 350 h for single cell).Moreover,the composite has an ultra-low TEC value(15.96×10^(-6)K^(-1)).This study proves that SFC+BZCY with triple conducting capacity is an excellent cathode for low-temperature PCFCs.
基金financially supported by China Post-doctoral Science Foundation(No.2022M710856)Guangzhou Postdoctoral Research Project(No.62104380)+2 种基金the Outstanding Youth Project of Natural Science Foundation of Guangdong Province(No.2022B1515020020)the Funding by Science and Technology Projects in Guangzhou(Nos.202206050003 and 202201010603)Guangdong Engineering Technology Research Center for Hydrogen Energy and Fuel Cells。
文摘Protonic ceramic fuel cells(PCFCs)have been attracting increasing attention because of their advances in high-efficiency power generation in an intermediate-temperature range,as compared to the high-temperature solid oxide fuel cells(SOFCs).The greatest difference between PCFCs and SOFCs is the specific requirement of protonic(H+)conductivity at the PCFC cathode,in addition to the electronic(e^(-))and oxide-ion(O^(2-))conductivity.The development of a triple H^(+)/e^(-)/O^(2-)conductor for PCFC cathode is still challenging.Thus,the most-widely used cathode material is based on the mature e^(-)/O^(2-)conductor.However,this leads to insufficient triple phase boundary(TPB),i.e.,reaction area.Herein,an efficient strategy that uses a~100 nm-thick proton conductive functional layer(La_(0.5)Sr_(0.5)CoO_(3-δ),LSC55)in-between the typical La_(0.8)Sr_(0.2)CoO_(3-δ)cathode(a mature e-/O^(2-)conductor,LS C 82)and B aZr_(0.4)Ce_(0.4)Y_(0.1)Yb_(0.)1O_(3-δ)elec trolyte(11 mm in diameter,20μm in thickness)is proposed to significantly enhance the reaction area.Reasonably,the ohmic resistance and polarization resistance are both decreased by 47%and 62%,respectively,compared with that of PCFCs without the functional layer.The power density of the PCFC with such a functional layer can be raised by up to 2.24 times,superior to those described in previous reports.The enhanced PCFC performances are attributed to the well-built TPB and enhanced reaction area via the functional layer engineering strategy.
基金supported by the National Natural Science Foundation of China(No.21978044).
文摘The performance degradation mechanism of ceramic fuel cell with NCAL(Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2))as symmetrical electrode and GDC as electrolyte in H2 is investigated.It is found that under the condition of 550◦C and constant current density of 0.2 A⋅cm^(-2),the output voltage of the cell is about 1.005 V in the initial 10 h and remains relatively stable.After 10 h,the voltage of the cell began to decrease gradually,and by 50 h,the voltage had decreased to 0.522 V.The results testing electrochemical performance of the cell and characterizing the cell materials before and after test using SEM,TOF-SIMS and FTIR indicate that the distribution of Li_(2)O/LiOH/Li_(2)CO_(3)compounds generated from NCAL anode in the cell plays a vital role in significantly improving the ionic conductivity of electrolyte and gas tightness of the cell.The dynamic migration of molten salt destroyed the continuity of molten salt in the cell,which in turn adversely impacted the ionic conductivity of electrolyte,gas tightness of the cell,and electrochemical reactions on both sides of the cathode and anode.These finally lead to the degradation of the cell performance.
文摘Protonic ceramic fuel cells(PCFCs)offer a convenient means for electrochemical conversion of chemical energy into electricity at intermediate temperatures with very high efficiency.Although BaCeO_(3)-and BaZrO_(3)-based complex oxides have been positioned as the most promising PCFC electrolytes,the design of new protonic conductors with improved properties is of paramount importance.Within the present work,we studied transport properties of scandium-doped barium stannate(Sc-doped BaSnO_(3)).Our analysis included the fabrication of porous and dense BaSn_(1−x)Sc_(x)O_(3−δ)ceramic materials(0≤x≤0.37),as well as a comprehensive analysis of their total,ionic,and electronic conductivities across all the experimental conditions realized under the PCFC operation:both air and hydrogen atmospheres with various water vapor partial pressures(p(H2O)),and a temperature range of 500–900℃.This work reports on electrolyte domain boundaries of the undoped and doped BaSnO_(3)for the first time,revealing that pure BaSnO_(3)exhibits mixed ionic–electronic conduction behavior under both oxidizing and reducing conditions,while the Sc-doping results in the gradual improvement of ionic(including protonic)conductivity,extending the electrolyte domain boundaries towards reduced atmospheres.This latter property makes the heavilydoped BaSnO_(3)representatives attractive for PCFC applications.
基金the support by the National Key R&D Program of China(2018YFE0124700)the National Natural Science Foundation of China(52102279,52072134,and 51972128)+1 种基金Natural Science Foundation of Shandong Province(ZR2021QE283)Department of Science and Technology of Hubei Province(2021CBA149 and 2021CFA072).
文摘Slow oxygen reduction reaction(ORR)involving proton transport remains the limiting factor for electrochemical performance of proton-conducting cathodes.To further reduce the operating temperature of protonic ceramic fuel cells(PCFCs),developing triple-conducting cathodes with excellent electrochemical performance is required.In this study,K-doped BaCo_(0.4)Fe_(0.4)Zr_(0.2)O_(3−δ)(BCFZ442)series were developed and used as the cathodes of the PCFCs,and their crystal structure,conductivity,hydration capability,and electrochemical performance were characterized in detail.Among them,Ba_(0.9)K_(0.1)Co_(0.4)Fe_(0.4)Zr_(0.2)O_(3−δ)(K10)cathode has the best electrochemical performance,which can be attributed to its high electron(e^(−))/oxygen ion(O^(2−))/H^(+)conductivity and proton uptake capacity.At 750℃,the polarization resistance of the K10 cathode is only 0.009Ω·cm^(2),the peak power density(PPD)of the single cell with the K10 cathode is close to 1 W·cm^(−2),and there is no significant degradation within 150 h.Excellent electrochemical performance and durability make K10 a promising cathode material for the PCFCs.This work can provide a guidance for further improving the proton transport capability of the triple-conducting oxides,which is of great significance for developing the PCFC cathodes with excellent electrochemical performance.
基金the National Natural Science Foundation of China(No.21978044,No.51834004)。
文摘Previous studies have found that the ceramic fuel cell using Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2)(NCAL)symmetrical electrode has obtained very good power generation performance in the temperature range of 450 to 550℃.Previous studies have pointed out that after being reduced by H2,NCAL anode will produce LiOH/Li2CO3 mixture and diffuse into the electrolyte,which results in the high ionic conductivity of the cell.In this study,the chemical reactivity of different oxide electrolytes such as CeO_(2),TiO_(2),ZrO_(2)and YSZ with LiOH and/or Li2CO3 and their effects on the electrochemical performance of the cell were studied.It is found that at 550◦C,only the open circuit voltage(OCV)of the cell using CeO_(2)as electrolyte can remain stable,and the maximum power density(MPD)of the CeO_(2)electrolyte cell reaches 599.6 mW⋅cm^(−2).The OCV of the cells with TiO_(2),ZrO_(2)and YSZ as electrolyte increased to the highest value within a few minutes,and the MPD of the cells was only more than 12 mW⋅cm^(−2).XRD,FT-IR,SEM-EDS and ICP-OES results indicate that the LiOH/Li2CO3 mixture diffuses into TiO_(2),ZrO_(2)and YSZ electrolytes and reacts with three oxides to produce Li2TiO3 and Li2ZrO3,respectively,which results in the low performance of the cell.
基金funding from the National Natural Science Foundation of China,China(12172104,52102226)the Shenzhen Science and Technology Innovation Commission,China(JCYJ20200109113439837)the Stable Supporting Fund of Shenzhen,China(GXWD2020123015542700320200728114835006)。
文摘A deep-learning-based framework is proposed to predict the impedance response and underlying electrochemical behavior of the reversible protonic ceramic cell(PCC) across a wide variety of different operating conditions.Electrochemical impedance spectra(EIS) of PCCs were first acquired under a variety of opera ting conditions to provide a dataset containing 36 sets of EIS spectra for the model.An artificial neural network(ANN) was then trained to model the relationship between the cell operating condition and EIS response.Finally,ANN model-predicted EIS spectra were analyzed by the distribution of relaxation times(DRT) and compared to DRT spectra obtained from the experimental EIS data,enabling an assessment of the accumulative errors from the predicted EIS data vs the predicted DRT.We show that in certain cases,although the R^(2)of the predicted EIS curve may be> 0.98,the R^(2)of the predicted DRT may be as low as~0.3.This can lead to an inaccurate ANN prediction of the underlying time-resolved electrochemical response,although the apparent accuracy as evaluated from the EIS prediction may seem acceptable.After adjustment of the parameters of the ANN framework,the average R^(2)of the DRTs derived from the predicted EIS can be improved to 0.9667.Thus,we demonstrate that a properly tuned ANN model can be used as an effective tool to predict not only the EIS,but also the DRT of complex electrochemical systems.
文摘Solid oxide fuel cells(SOFCs)and electrolysis cells(SOECs)are promising energy conversion devices,on whose basis green hydrogen energy technologies can be developed to support the transition to a carbon-free future.As compared with oxygen-conducting cells,the operational temperatures of protonic ceramic fuel cells(PCFCs)and electrolysis cells(PCECs)can be reduced by several hundreds of degrees(down to low-and intermediatetemperature ranges of 400–700C)while maintaining high performance and efficiency.This is due to the distinctive characteristics of charge carriers for proton-conducting electrolytes.However,despite achieving outstanding lab-scale performance,the prospects for industrial scaling of PCFCs and PCECs remain hazy,at least in the near future,in contrast to commercially available SOFCs and SOECs.In this review,we reveal the reasons for the delayed technological development,which need to be addressed in order to transfer fundamental findings into industrial processes.Possible solutions to the identified problems are also highlighted.
文摘In recent years, interest in hydrogen as a fuel has sharply increased in the field of alternative and green energy due to its high energy capability and zero-emission behaviour. As a result, research in the development of new highly efficient methods for producing high-purity hydrogen is relevant. This paper presents, for the first time, the test results of an electrochemical cell with a proton-conducting La_(0.9)Sr_(0.1)ScO_(3-δ) electrolyte and symmetrical Sr_(1.95)Fe_(1.4)Ni_(0.1)Mo_(0.5)O_(6-δ)+ La_(0.9)Sr_(0.1)Sc_(0.9)Co_(0.1)O_(3-δ) electrodes as a hybrid setup for electricity generation in proton ceramic fuel cell mode, for hydrogen separation from H_(2)+ Ar mixture and the production of high-purity hydrogen from methane with simultaneous CO_(2) utilization.It was found that this electrochemical cell generates high flow rates of hydrogen during its separation through a proton-conducting membrane from H_(2)+ Ar mixture, about 500 cm^(3)h^(-1)cm^(-2)at a current density of 0.6 A cm^(-2)as well as about 370 cm^(3) h^(-1)cm^(-2)at a current density of 0.5 A cm^(-2) from CH_(4)+ CO_(2) mixture at 800 ℃ which shows that these cells are promising for hydrogen production.
基金National Natural Science Foundation of China,Grant/Award Numbers:52272216,51972183Hundred Youth Talents Program of HunanStartup Funding for Talents at University of South China。
文摘The development of proton,oxygen-ion,and electron mixed conducting materials,known as triple-conduction materials,as cathodes for proton-conducting solid oxide fuel cells(H-SOFCs)is highly desired because they can increase fuel cell performance by extending the reaction active area.Although oxygen-ion and electron conductions can be measured directly,proton conduction in these oxides is usually estimated indirectly.Because of the instability of cathode materials in a reducing environment,direct measurement of proton conduction in cathode oxide is difficult.The La0.8Sr0.2Sc0.5Fe0.5O3–δ(LSSF)cathode material is proposed for H-SOFCs in this study,which can survive in an H_(2)-containing atmosphere,allowing measurement of proton conduction in LSSF by hydrogen permeation technology.Furthermore,LSSF is discovered to be a unique proton and electron mixed-conductive material with limited oxygen diffusion capability that is specifically designed for H-SOFCs.The LSSF is an appealing cathode choice for H-SOFCs due to its outstanding CO_(2)tolerance and matched thermal expansion coefficient,producing a record-high performance of 2032 mW cm^(−2)at 700℃and good long-term stability under operational conditions.The current study reveals that a new type of proton–electron mixed conducting cathode can provide promising performance for H-SOFCs,opening the way for developing high-performance cathodes.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.2019GF10).
文摘New two-layer Ruddlesden-Popper(RP)oxide La_(0.25)Sr_(2.75)FeNiO_(7-δ)(LSFN)in the combination of Sr_(3)Fe_(2)O_(7-δ) and La_(3)Ni_(2)O_(7-δ) was successfully synthesized and studied as the potential active single-phase and composite cathode for protonic ceramics fuel cells(PCFCs).LSFN with the tetragonal symmetrical structure(IMmmm)is confinned,and the co-existence of Fe^(3+)/Fe^(4+) and Ni^(3+)/Ni^(2+) couples is demonstrated by X-ray photoelectron spectrometer(XPS)analysis.The LSFN conductivity is apparently enhanced after Ni doping in Fe-site,and nearly three times those of Sr_(3)Fe_(2)O_(7-δ),which is directly related to the carrier concentration and conductor mechanism.Importantly,anode supported PCFCs using LSFN-BaZr_(0.1)Ce_(0.7)Y_(0.2)O_(3-δ)(LSFN-BZCY)composite cathode achieved high power density(426 mW·cm^(-2) at 650℃)and low electrode interface polarization resistance(0.26Ω·cm^(2)).Besides,distribution of relaxation time(DRT)function technology was further used to analyse the electrode polarization processes.The observed three peaks(Pl,P2,and P3)separated by DRT shifted to the high frequency region with the decreasing temperature,suggesting that the charge transfer at the electrode-electrolyte interfaces becomes more difficult at reduced temperatures.Preliminary results demonstrate that new two-layer RP phase LSFN can be a promising cathode candidate for PCFCs.
基金The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China under Grant[U1737205 and 51805114]the China Postdoctoral Science Foundation 2019TQ0075.
文摘One of the critical challenges for the protonic ceramic fuel cell stack is sealing electrolytes and interconnects.However,the traditional AgeCuO sealant will aggravate the oxidation along the interconnect surface and result in brittle compound layers at the BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)(BZCYYb)electrolyte interface.The present work demonstrates that a silver particle interlayer with high dislocation density can be adopted to join BZCYYb electrolyte to the interconnect(AISI 441 stainless)in air instead of traditional AgeCuO sealant.Elevating temperatures result in a sufficient bonding at the Ag/BZCYYb interface,and a defect-free joint is obtained at 950℃.Atomic bonding at Ag/BZCYYb interface is confirmed by TEM.Also,a dense and thin oxide layer(2-3 μm)is formed along the AISI 441 interface.Ag particles in the interlayer provide the main driving force for the sintering joining.The massive dislocations promote the recovery and recrystallization of the Ag interlayer,as well as the interdiffusion of BZCYYb/Ag.After aging in the wet oxidizing atmosphere at 600℃ for 300 h,joints remain intact and dense,indicating superior oxidation resistance and aging performance.Besides,the joint shear strength(25.3 MPa)is 59%higher than that of the joint brazed by traditional AgeCuO.
