Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell technologies.However,traditional SOFCs s...Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell technologies.However,traditional SOFCs suffer from having a higher volume,current leakage,complex connections,and difficulty in gas sealing.To solve these problems,Rolls-Royce has fabricated a simple design by stacking cells in series on an insulating porous support,resulting in the tubular segmented-in-series solid oxide fuel cells(SIS-SOFCs),which achieved higher output voltage.This work systematically reviews recent advances in the structures,preparation methods,perform-ances,and stability of tubular SIS-SOFCs in experimental and numerical studies.Finally,the challenges and future development of tubular SIS-SOFCs are also discussed.The findings of this work can help guide the direction and inspire innovation of future development in this field.展开更多
For present solid oxide fuel cells(SOFCs),rapid performance degradation is observed in the initial aging process,and the dis-cussion of the degradation mechanism necessitates quantitative analysis.Herein,focused ion b...For present solid oxide fuel cells(SOFCs),rapid performance degradation is observed in the initial aging process,and the dis-cussion of the degradation mechanism necessitates quantitative analysis.Herein,focused ion beam-scanning electron microscopy was em-ployed to characterize and reconstruct the ceramic microstructures of SOFC anodes.The lattice Boltzmann method(LBM)simulation of multiphysical and electrochemical processes in the reconstructed models was performed.Two samples collected from industrial-size cells were characterized,including a reduced reference cell and a cell with an initial aging process.Statistical parameters of the reconstructed microstructures revealed a significant decrease in the active triple-phase boundary and Ni connectivity in the aged cell compared with the reference cell.The LBM simulation revealed that activity degradation is dominant compared with microstructural degradation during the initial aging process,and the electrochemical reactions spread to the support layer in the aged cell.The microstructural and activity de-gradations are attributed to Ni migration and coarsening.展开更多
Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical commercialization.Herein,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)...Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical commercialization.Herein,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)FeO_(3-δ) perovskites as highly-active catalysts for LT-SOFCs.Sm doping can significantly enhance the electrocata lytic activity and chemical stability of cathode.At 600℃,Bi_(0.675)Sm_(0.025)Sr_(0.3)FeO_(3-δ)(BSSF25) cathode has been found to be the optimum composition with a polarization resistance of 0.098 Ω cm^2,which is only around 22.8% of Bi_(0.7)Sr_(0.3)FeO_(3-δ)(BSF).A full cell utilizing BSSF25 displays an exceptional output density of 790 mW cm^(-2),which can operate continuously over100 h without obvious degradation.The remarkable electrochemical performance observed can be attributed to the improved O_(2) transport kinetics,superior surface oxygen adsorption capacity,as well as O_(2)p band centers in close proximity to the Fermi level.Moreover,larger average bonding energy(ABE) and the presence of highly acidic Bi,Sm,and Fe ions restrict the adsorption of CO_(2) on the cathode surface,resulting in excellent CO_(2) resistivity.This work provides valuable guidance for systematic design of efficient and durable catalysts for LT-SOFCs.展开更多
Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects o...Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects of cell operating conditions on the terminal voltage and anode microstructure of a Ni-yttria-stabilized zirconia anode-supported single cell were investigated.The microstructure of the anode active area near the electrolyte was characterized by laser optical microscopy and focused ion beam-scanning electron microscopy.Ni depletion at the anode/electrolyte interface region was observed after 100 h discharge tests.In addition,the long-term stability of the single cell was evaluated at 700℃for 3000 h.After an initial decline,the anode-supported single cell exhibits good durability with a voltage decay rate of 0.72%/kh and an electrode polarization resistance decay rate of 0.17%/kh.The main performance loss of the cell originates from the initial degradation.展开更多
Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscalin...Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscaling for industrial applications.GDC thin films were successfully fabricated through reactive sputtering using a Gd_(0.2)Ce_(0.8)(at%)metallic target,and their application in solid oxide fuel cells,such as buffer layers between yttria-stabilized zirconia(YSZ)/La0.6Sr0.4Co0.2Fe0.8O_(3−δ)and as sublayers in the steel/coating system,was evaluated.First,the direct current(DC)reactive-sputtering behavior of the GdCe metallic target was determined.Then,the GDC films were deposited on NiO-YSZ/YSZ half-cells to investigate the influence of oxygen flow rate on the quality of annealed GDC films.The results demonstrated that reactive sputtering can be used to prepare thin and dense GDC buffer layers without high-temperature sintering.Furthermore,the cells with a sputtered GDC buffer layer showed better electrochemical performance than those with a screen-printed GDC buffer layer.In addition,the insertion of a GDC sublayer between the SUS441 interconnects and the Mn-Co spinel coatings contributed to the reduction of the oxidation rate for SUS441 at operating temperatures,according to the area-specific resistance tests.展开更多
This article delivers a robust overview of potential electrode materials for use in symmetrical solid oxide fuel cells(S-SOFCs),a relatively new SOFC technology.To this end,this article provides a comprehensive review...This article delivers a robust overview of potential electrode materials for use in symmetrical solid oxide fuel cells(S-SOFCs),a relatively new SOFC technology.To this end,this article provides a comprehensive review of recent advances and progress in electrode materials for S-SOFC,discussing both the selection of materials and the challenges that come with making that choice.This article discussed the relevant factors involved in developing electrodes with nano/microstructure.Nanocomposites,e.g.,non-cobalt and lithiated materials,are only a few of the electrode types now being researched.Furthermore,the phase structure and microstructure of the produced materials are heavily influenced by the synthesis procedure.Insights into the possibilities and difficulties of the material are discussed.To achieve the desired microstructural features,this article focuses on a synthesis technique that is either the most recent or a better iteration of an existing process.The portion of this analysis that addresses the risks associated with manufacturing and the challenges posed by materials when fabricating S-SOFCs is the most critical.This article also provides important and useful recommendations for the strategic design of electrode materials researchers.展开更多
This paper presents a review of low molecular weight alkane-fed solid oxide fuel cells(SOFCs),which,unlikely the conventional use of SOFCs for only power production,are utilized to cogenerate produce useful chemicals ...This paper presents a review of low molecular weight alkane-fed solid oxide fuel cells(SOFCs),which,unlikely the conventional use of SOFCs for only power production,are utilized to cogenerate produce useful chemicals at the same time.The cogeneration processes in SOFC have been classified according to the different types of fuel.C_(2)and C_(3)alkenes and synthesis gas are the main cogenerated chemicals together with electricity.The chemicals and energy cogeneration in a fuel cell reactor seems to be an effective alternative to conventional reactors for only chemicals production and conventional fuel cells for only power production.Although,the use of SOFCs for chemicals and energy cogeneration has proved successful in the industrial setting,the development of new catalysts aimed at obtaining the desired chemicals together with the production of a high amount of energy,and optimizing SOFC operation conditions is still a challenge to enhance system performance and make commercial applications workable.展开更多
Sluggish oxygen reduction reaction(ORR)kinetics are a major obstacle to developing intermediate-temperature solid-oxide fuel cells(IT-SOFCs).In particular,engineering the anion defect concentration at an interface bet...Sluggish oxygen reduction reaction(ORR)kinetics are a major obstacle to developing intermediate-temperature solid-oxide fuel cells(IT-SOFCs).In particular,engineering the anion defect concentration at an interface between the cathode and electrolyte is important for facilitating ORR kinetics and hence improving the electrochemical performance.We developed the yttria-stabilized zirconia(YSZ)nanofiber(NF)-based composite cathode,where the oxygen vacancy concentration is controlled by varying the dopant cation(Y2O3)ratio in the YSZ NFs.The composite cathode with the optimized oxygen vacancy concentration exhibits maximum power densities of 2.66 and 1.51 W cm^(−2)at 700 and 600℃,respectively,with excellent thermal stability at 700℃ over 500 h under 1.0 A cm^(−2).Electrochemical impedance spectroscopy and distribution of relaxation time analysis revealed that the high oxygen vacancy concentration in the NF-based scaffold facilitates the charge transfer and incorporation reaction occurred at the interfaces between the cathode and electrolyte.Our results demonstrate the high feasibility and potential of interface engineering for achieving IT-SOFCs with higher performance and stability.展开更多
Thermal management in solid oxide fuel cells(SOFC)is a critical issue due to non-uniform electrochemical reactions and convective fl ows within the cells.Therefore,a 2D mathematical model is established herein to inve...Thermal management in solid oxide fuel cells(SOFC)is a critical issue due to non-uniform electrochemical reactions and convective fl ows within the cells.Therefore,a 2D mathematical model is established herein to investigate the thermal responses of a tubular methanol-fueled SOFC.Results show that unlike the low-temperature condition of 873 K,where the peak temperature gradient occurs at the cell center,it appears near the fuel inlet at 1073 K because of the rapid temperature rise induced by the elevated current density.Despite the large heat convection capacity,excessive air could not eff ectively eliminate the harmful temperature gradient caused by the large current density.Thus,optimal control of the current density by properly selecting the operating potential could generate a local thermal neutral state.Interestingly,the maximum axial temperature gradient could be reduced by about 18%at 973 K and 20%at 1073 K when the air with a 5 K higher temperature is supplied.Additionally,despite the higher electrochemical performance observed,the cell with a counter-fl ow arrange-ment featured by a larger hot area and higher maximum temperature gradients is not preferable for a ceramic SOFC system considering thermal durability.Overall,this study could provide insightful thermal information for the operating condition selection,structure design,and stability assessment of realistic SOFCs combined with their internal reforming process.展开更多
Solid oxide fuel cell(SOFC) technology and its status and problems were briefly described.Several topics for furtherresearch and development were proposed.
Carbon-fueled solid oxide fuel cells(CF-SOFCs)can electrochemically convert the chemical energy in carbon into electricity,which demonstrate both superior electrical efficiency and fuel utilisation compared to all oth...Carbon-fueled solid oxide fuel cells(CF-SOFCs)can electrochemically convert the chemical energy in carbon into electricity,which demonstrate both superior electrical efficiency and fuel utilisation compared to all other types of fuel cells.However,using solid carbon as the fuel of SOFCs also faces some challenges,the fluid mobility and reactive activity of carbon-based fuels are much lower than those of gaseous fuels.Therefore,the anode reaction kinetics plays a crucial role in determining the electrochemical performance of CF-SOFCs.Herein,the progress of various anodes in CF-SOFCs is reviewed from the perspective of material compositions,electrochemical performance and microstructures.Challenges faced in developing high performance anodes for CF-SOFCs are also discussed.展开更多
Biomass,a source of renewable energy,represents an effective substitute to fossil fuels.Gasification is a process that organics are thermochemically converted into valuable gaseous products(e.g.biogas).In this work,th...Biomass,a source of renewable energy,represents an effective substitute to fossil fuels.Gasification is a process that organics are thermochemically converted into valuable gaseous products(e.g.biogas).In this work,the catalytic test demonstrated that the biogas produced from biomass gasification mainly consists of H2,CH4,CO,and CO2,which were then be used as the fuel for solid oxide fuel cell(SOFC).Planar SOFCs were fabricated and adopted.The steam reforming of biogas was carried out at the anode of a SOFC to obtain a hydrogen-rich fuel.The performance of the SOFCs operating on generated biogas was investigated by I-V polarization and electrochemical impedance spectra characterizations.An excellent cell performance was obtained,for example,the peak power density of the SOFC reached 1391 mW·cm-2 at 750℃when the generated biogas was used as the fuel.Furthermore,the SOFC fuelled by simulated biogas delivered a very stable operation.展开更多
The cell performance and temperature gradient of a tubular solid oxide fuel cell with indirect internal reformer (IIR-SOFC) fuelled by natural gas, containing a typical catalytic packed-bed reformer, a catalytic coa...The cell performance and temperature gradient of a tubular solid oxide fuel cell with indirect internal reformer (IIR-SOFC) fuelled by natural gas, containing a typical catalytic packed-bed reformer, a catalytic coated wall reformer, a catalytic annular reformer, and a novel catalytic annular-coated wall reformer were investigated with an aim to determine the most efficient internal reformer system. Among the four reformer designs, IIR-SOFC containing an annular-coated wall reformer exhibited the highest performance in terms of cell power density (0.67 W.cm 2) and electrical efficiency (68%) with an acceptable temperature gradient and a moderate pressure drop across the reformer (3.53 × 10 5 kPa). IIR-SOFC with an annular-coated wall reformer was then studied over a range of operating conditions: inlet fuel temperature, operating pressure, steam to carbon (S : C) ratio, gas flow pattern (co-flow and counter-flow pattern), and natural gas compositions. The simulation results showed that the temperature gradient across the reformer could not be decreased using a lower fuel inlet temperature (1223 K-1173 K) and both the power density and electrical efficiency of the cell also decreased by lowering fuel inlet temperature. Operating in higher pressure mode (1-10 bar) improved the temperature gradient and cell performance. Increasing the S : C ratio from 2 : 1 to 4:1 could decrease the temperature drop across the reformer but also decrease the cell performance. The average temperature gradient was higher and smoother in IIR-SOFC under a co-flow pattern than that under a counter-flow pattern, leading to lower overpotential and higher cell performance. Natural gas compositions significantly affected the cell performance and temperature gradient. Natural gas containing lower methane content provided smoother temperature gradient in the system but showed lower power density and electrical efficiency.展开更多
Accurate prediction of performance degradation in complex systems such as solid oxide fuel cells is crucial for expediting technological advancements.However,significant challenges still persist due to limited compreh...Accurate prediction of performance degradation in complex systems such as solid oxide fuel cells is crucial for expediting technological advancements.However,significant challenges still persist due to limited comprehension of degradation mechanisms and difficulties in acquiring in-situ features.In this study,we propose an effective approach that integrates long short-term memory(LSTM) neural network and dynamic electrochemical impedance spectroscopy(DEIS).This integrated approach enables precise prediction of future evolutions in both current-voltage and EIS features using historical testing data,without prior knowledge of degradation mechanisms.For short-term predictions spanning hundreds of hours,our approach achieves a prediction accuracy exceeding 0.99,showcasing promising prospects for diagnostic applications.Additionally,for long-term predictions spanning thousands of hours,we quantitatively determine the significance of each degradation mechanism,which is crucial for enhancing cell durability.Moreover,our proposed approach demonstrates satisfactory predictive ability in both time and frequency domains,offering the potential to reduce EIS testing time by more than half.展开更多
A solid state H2S/air electrochemical cell having the configuration of H2S, (MoS2+NiS+Ag)/YSZ/Pt,air has been examined with different H2S flow rates and concentrations at atmospheric pressure and 750-850℃.Performance...A solid state H2S/air electrochemical cell having the configuration of H2S, (MoS2+NiS+Ag)/YSZ/Pt,air has been examined with different H2S flow rates and concentrations at atmospheric pressure and 750-850℃.Performance of the fuel cell was dependent on anode compartment H2S flow rate and concentration. The cell open-circuit voltage increased with increasing H2S flow rate. It was found that increasing both H2S flow rate and H2S concentration improved current-voltage and power density performance. This is resulted from improved gas diffusion in anode and increased concentration of anodic electroactive species. Operation at elevated H2S concentration improved the cell performance at a given gas flow rate. However, as low as 5% H2S in gas mixture can also be utilized as fuel feed to cells. Highest current and power densities, 1750mA·cm^-2 and 200mW·cm^-2,are obtained with pure H2S flow rate of 50 ml·min^-1 and air flow rate of 100ml·min^-1 at 850℃.展开更多
Glass-ceramic materials were developed as a sealant in the solid oxide fuel cell (SOFC) in the temperature range of 800 -850 ℃. The glass materials were based on the glass and glass-ceramic in the BaO-CaO-Al2O3-SiO...Glass-ceramic materials were developed as a sealant in the solid oxide fuel cell (SOFC) in the temperature range of 800 -850 ℃. The glass materials were based on the glass and glass-ceramic in the BaO-CaO-Al2O3-SiO2-La2O3-B2O3 system. The thermal expansion coefficient (TEC) decreased with lower Ba^2+ content and higher Ca^2+ content, but the glass transition temperature and crystallization temperature increased greatly with an increase in Ca^2+ content and a decrease in Ba^2+ content, when the other components in the sealant were invariable. The TEC of the sealant with Ba^2+ content of 25.4% was 10.8 × 10^-6 K^- 1(temperature range from 25 to 850℃), and its softening temperature was 950 ℃. The TEC of the sealant accorded well with that of La0.9Sr0.1Ga0.5Mg0.2o3- 6(LSGM) with a mismatch of only 3%. The sealant had superior stability and compatibility with the LSGM electrolyte during the process of operation in SOFC. The weight loss of the sealant with Ba^2+ content of 25.4% was approfimately zero after heat-treated at 800℃ for 500 h in H2 and O2 atmosphere, respectively.展开更多
A simulation model was developed to analyze the steady state and transient operation of a tubular solid oxide fuel cell. The model covers both the electrochemical and the heat transfer models. The electrochemical mode...A simulation model was developed to analyze the steady state and transient operation of a tubular solid oxide fuel cell. The model covers both the electrochemical and the heat transfer models. The electrochemical model deals with the Nernst potential, ohmic polarization, activation polarization, and concentration polarization, while the heat transfer model concerns the heat transfer by conduction, convection and radiation. The numerical results show that the ohmic loss is the dominant one among the three polarizations in a cathode-supported solid oxide fuel cell and in the middle part of a solid oxide fuel cell the temperature is higher than those at both the ends. When the inlet temperature and the flow rates of the fuel and the oxidant are kept constantly, the temperature of the solid structure of the cell will increase due to the increase of power output of the cell from the initial state to the new one.展开更多
A Gd-doped ceria(GDC) buffer layer is required between a conventional yttria-stabilized zirconia(YSZ) electrolyte and a La-Sr-Co-Fe-O3(LSCF) cathode to prevent their chemical reaction. In this study,the effect o...A Gd-doped ceria(GDC) buffer layer is required between a conventional yttria-stabilized zirconia(YSZ) electrolyte and a La-Sr-Co-Fe-O3(LSCF) cathode to prevent their chemical reaction. In this study,the effect of varying the conditions for fabricating the GDC buffer layer, such as sintering temperature and amount of sintering aid, on the solid oxide fuel cell(SOFC) performance was investigated. A finer GDC powder(i.e., ultra-high surface area), a higher sintering temperature(1290℃), and a larger amount of sintering aid(12%) resulted in improved densification of the buffer layer; however, the electrochemical performance of an anode-supported cell containing this GDC buffer layer was poor. These conflicting results are attributed to the formation of(Zr, Ce)O2 and/or excess cobalt grain boundaries(GBs) at higher sintering temperatures with a large amount of sintering aid(i.e., cobalt oxide). A cell comprising of a cobalt-free GDC buffer layer, which was fabricated using a low-temperature process, had lower cell resistance and higher stability. The results indicate that electrochemical performance and stability of SOFCs strongly depend on fabrication conditions for the GDC buffer layer.展开更多
La1-xSrxGa1-yMgyO3-δ (LSGM) electrolyte, La1-xSrxCr1-yMnyO3-δ (LSCM) anode and La1-xSrxFe1-yMnyO3-δ (LSFM) cathode materials were all synthesized by glycine-nitrate process (GNP). The microstructure and characteris...La1-xSrxGa1-yMgyO3-δ (LSGM) electrolyte, La1-xSrxCr1-yMnyO3-δ (LSCM) anode and La1-xSrxFe1-yMnyO3-δ (LSFM) cathode materials were all synthesized by glycine-nitrate process (GNP). The microstructure and characteristics of LSGM, LSCM and LSFM were tested via X-ray diffraction(XRD), scanning electron microcopy (SEM), A C impedance and four-probe direct current techniques. XRD shows that pure perovskite phase LSGM electrolyte and electrode (LSCM anode and LSFM cathode) materials were prepared after being sintered at 1400 ℃ for 20 h and at 1000 ℃ for 5 h, respectively. The max conductivities of LSGM (ionic conductivity), LSCM (total conductivity) and LSFM (total conductivity) materials are 0.02, 10, 16 S·cm-1 in the air below 850 ℃, respectively. The conductivity of LSCM becomes smaller when the atmosphere changes from air to pure hydrogen at the same temperature and it decreases with the temperature like metal. The porous and LSGM-based LSCM anode and LSFM cathode films were prepared by screen printing method, and the sintering temperatures for them were 1300 and 1250 ℃, respectively. LSGM and electrode (LSCM and LSFM) materials have good thermal and chemical compatibility.展开更多
Ceria-based heterostructure composite(CHC)has become a new stream to develop advanced low-temperature(300–600°C)solid oxide fuel cells(LTSOFCs)with excellent power outputs at 1000 mW cm−2 level.The state-ofthe-a...Ceria-based heterostructure composite(CHC)has become a new stream to develop advanced low-temperature(300–600°C)solid oxide fuel cells(LTSOFCs)with excellent power outputs at 1000 mW cm−2 level.The state-ofthe-art ceria–carbonate or ceria–semiconductor heterostructure composites have made the CHC systems significantly contribute to both fundamental and applied science researches of LTSOFCs;however,a deep scientific understanding to achieve excellent fuel cell performance and high superionic conduction is still missing,which may hinder its wide application and commercialization.This review aims to establish a new fundamental strategy for superionic conduction of the CHC materials and relevant LTSOFCs.This involves energy band and built-in-field assisting superionic conduction,highlighting coupling effect among the ionic transfer,band structure and alignment impact.Furthermore,theories of ceria–carbonate,e.g.,space charge and multi-ion conduction,as well as new scientific understanding are discussed and presented for functional CHC materials.展开更多
基金supported by the National Natural Science Foundation of China (Nos.21701083 and 22179054).
文摘Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell technologies.However,traditional SOFCs suffer from having a higher volume,current leakage,complex connections,and difficulty in gas sealing.To solve these problems,Rolls-Royce has fabricated a simple design by stacking cells in series on an insulating porous support,resulting in the tubular segmented-in-series solid oxide fuel cells(SIS-SOFCs),which achieved higher output voltage.This work systematically reviews recent advances in the structures,preparation methods,perform-ances,and stability of tubular SIS-SOFCs in experimental and numerical studies.Finally,the challenges and future development of tubular SIS-SOFCs are also discussed.The findings of this work can help guide the direction and inspire innovation of future development in this field.
基金the National Key R&D Program of China(No.2018YFB1502201)the Guangdong Basic and Applied Basic Research Foundation,China(No.2020A1515010551).
文摘For present solid oxide fuel cells(SOFCs),rapid performance degradation is observed in the initial aging process,and the dis-cussion of the degradation mechanism necessitates quantitative analysis.Herein,focused ion beam-scanning electron microscopy was em-ployed to characterize and reconstruct the ceramic microstructures of SOFC anodes.The lattice Boltzmann method(LBM)simulation of multiphysical and electrochemical processes in the reconstructed models was performed.Two samples collected from industrial-size cells were characterized,including a reduced reference cell and a cell with an initial aging process.Statistical parameters of the reconstructed microstructures revealed a significant decrease in the active triple-phase boundary and Ni connectivity in the aged cell compared with the reference cell.The LBM simulation revealed that activity degradation is dominant compared with microstructural degradation during the initial aging process,and the electrochemical reactions spread to the support layer in the aged cell.The microstructural and activity de-gradations are attributed to Ni migration and coarsening.
基金supported by the National Natural Science Foundation of China(22279025,21773048)the Natural Science Foundation of Heilongjiang Province(LH2021A013)+1 种基金the Sichuan Science and Technology Program(2021YFSY0022)the Fundamental Research Funds for the Central Universities(2023FRFK06005,HIT.NSRIF202204)。
文摘Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical commercialization.Herein,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)FeO_(3-δ) perovskites as highly-active catalysts for LT-SOFCs.Sm doping can significantly enhance the electrocata lytic activity and chemical stability of cathode.At 600℃,Bi_(0.675)Sm_(0.025)Sr_(0.3)FeO_(3-δ)(BSSF25) cathode has been found to be the optimum composition with a polarization resistance of 0.098 Ω cm^2,which is only around 22.8% of Bi_(0.7)Sr_(0.3)FeO_(3-δ)(BSF).A full cell utilizing BSSF25 displays an exceptional output density of 790 mW cm^(-2),which can operate continuously over100 h without obvious degradation.The remarkable electrochemical performance observed can be attributed to the improved O_(2) transport kinetics,superior surface oxygen adsorption capacity,as well as O_(2)p band centers in close proximity to the Fermi level.Moreover,larger average bonding energy(ABE) and the presence of highly acidic Bi,Sm,and Fe ions restrict the adsorption of CO_(2) on the cathode surface,resulting in excellent CO_(2) resistivity.This work provides valuable guidance for systematic design of efficient and durable catalysts for LT-SOFCs.
基金supported by the National Key R&D Program of China(No.2018YFB1502202)the Fundamental Research Funds for the Central Universities(No.FRF-GF-20-09B).
文摘Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects of cell operating conditions on the terminal voltage and anode microstructure of a Ni-yttria-stabilized zirconia anode-supported single cell were investigated.The microstructure of the anode active area near the electrolyte was characterized by laser optical microscopy and focused ion beam-scanning electron microscopy.Ni depletion at the anode/electrolyte interface region was observed after 100 h discharge tests.In addition,the long-term stability of the single cell was evaluated at 700℃for 3000 h.After an initial decline,the anode-supported single cell exhibits good durability with a voltage decay rate of 0.72%/kh and an electrode polarization resistance decay rate of 0.17%/kh.The main performance loss of the cell originates from the initial degradation.
基金financially supported by the National Key R&D Program of China (No. 2018YFB1502203-1)the Guangdong Basic and Applied Basic Research Foundation (No. 2021B1515120087)the Stable Supporting Fund of Shenzhen, China (No. GXWD20201230155427003-202007 28114835006)
文摘Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscaling for industrial applications.GDC thin films were successfully fabricated through reactive sputtering using a Gd_(0.2)Ce_(0.8)(at%)metallic target,and their application in solid oxide fuel cells,such as buffer layers between yttria-stabilized zirconia(YSZ)/La0.6Sr0.4Co0.2Fe0.8O_(3−δ)and as sublayers in the steel/coating system,was evaluated.First,the direct current(DC)reactive-sputtering behavior of the GdCe metallic target was determined.Then,the GDC films were deposited on NiO-YSZ/YSZ half-cells to investigate the influence of oxygen flow rate on the quality of annealed GDC films.The results demonstrated that reactive sputtering can be used to prepare thin and dense GDC buffer layers without high-temperature sintering.Furthermore,the cells with a sputtered GDC buffer layer showed better electrochemical performance than those with a screen-printed GDC buffer layer.In addition,the insertion of a GDC sublayer between the SUS441 interconnects and the Mn-Co spinel coatings contributed to the reduction of the oxidation rate for SUS441 at operating temperatures,according to the area-specific resistance tests.
基金the Fundamental Research Grant Scheme (FRGS),grant No.FRGS/1/2021/TK0/UKM/01/5 funded by the Ministry of Higher Education (MOHE)。
文摘This article delivers a robust overview of potential electrode materials for use in symmetrical solid oxide fuel cells(S-SOFCs),a relatively new SOFC technology.To this end,this article provides a comprehensive review of recent advances and progress in electrode materials for S-SOFC,discussing both the selection of materials and the challenges that come with making that choice.This article discussed the relevant factors involved in developing electrodes with nano/microstructure.Nanocomposites,e.g.,non-cobalt and lithiated materials,are only a few of the electrode types now being researched.Furthermore,the phase structure and microstructure of the produced materials are heavily influenced by the synthesis procedure.Insights into the possibilities and difficulties of the material are discussed.To achieve the desired microstructural features,this article focuses on a synthesis technique that is either the most recent or a better iteration of an existing process.The portion of this analysis that addresses the risks associated with manufacturing and the challenges posed by materials when fabricating S-SOFCs is the most critical.This article also provides important and useful recommendations for the strategic design of electrode materials researchers.
文摘This paper presents a review of low molecular weight alkane-fed solid oxide fuel cells(SOFCs),which,unlikely the conventional use of SOFCs for only power production,are utilized to cogenerate produce useful chemicals at the same time.The cogeneration processes in SOFC have been classified according to the different types of fuel.C_(2)and C_(3)alkenes and synthesis gas are the main cogenerated chemicals together with electricity.The chemicals and energy cogeneration in a fuel cell reactor seems to be an effective alternative to conventional reactors for only chemicals production and conventional fuel cells for only power production.Although,the use of SOFCs for chemicals and energy cogeneration has proved successful in the industrial setting,the development of new catalysts aimed at obtaining the desired chemicals together with the production of a high amount of energy,and optimizing SOFC operation conditions is still a challenge to enhance system performance and make commercial applications workable.
基金supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean government (MSIT)(Nos. 2022R1A2C3012372 and 2022R1A4A1031182)Korea Institute for Advancement of Technology(KIAT)Competency Development Program for Industry Specialists of Korean Ministry of Trade,Industry and Energy Grant funded by the Korea Government(MOTIE)(No. P0008458, The Competency Development Program for Industry Specialist and No. P0017120, HRD program for Foster R&D specialist of parts for ecofriendly vehicle (xEV))
文摘Sluggish oxygen reduction reaction(ORR)kinetics are a major obstacle to developing intermediate-temperature solid-oxide fuel cells(IT-SOFCs).In particular,engineering the anion defect concentration at an interface between the cathode and electrolyte is important for facilitating ORR kinetics and hence improving the electrochemical performance.We developed the yttria-stabilized zirconia(YSZ)nanofiber(NF)-based composite cathode,where the oxygen vacancy concentration is controlled by varying the dopant cation(Y2O3)ratio in the YSZ NFs.The composite cathode with the optimized oxygen vacancy concentration exhibits maximum power densities of 2.66 and 1.51 W cm^(−2)at 700 and 600℃,respectively,with excellent thermal stability at 700℃ over 500 h under 1.0 A cm^(−2).Electrochemical impedance spectroscopy and distribution of relaxation time analysis revealed that the high oxygen vacancy concentration in the NF-based scaffold facilitates the charge transfer and incorporation reaction occurred at the interfaces between the cathode and electrolyte.Our results demonstrate the high feasibility and potential of interface engineering for achieving IT-SOFCs with higher performance and stability.
基金by the Project of Strategic Importance Funding Scheme from The Hong Kong China Polytechnic University(No.P0035168)the National Natural Science Foundation of China(No.51806241).
文摘Thermal management in solid oxide fuel cells(SOFC)is a critical issue due to non-uniform electrochemical reactions and convective fl ows within the cells.Therefore,a 2D mathematical model is established herein to investigate the thermal responses of a tubular methanol-fueled SOFC.Results show that unlike the low-temperature condition of 873 K,where the peak temperature gradient occurs at the cell center,it appears near the fuel inlet at 1073 K because of the rapid temperature rise induced by the elevated current density.Despite the large heat convection capacity,excessive air could not eff ectively eliminate the harmful temperature gradient caused by the large current density.Thus,optimal control of the current density by properly selecting the operating potential could generate a local thermal neutral state.Interestingly,the maximum axial temperature gradient could be reduced by about 18%at 973 K and 20%at 1073 K when the air with a 5 K higher temperature is supplied.Additionally,despite the higher electrochemical performance observed,the cell with a counter-fl ow arrange-ment featured by a larger hot area and higher maximum temperature gradients is not preferable for a ceramic SOFC system considering thermal durability.Overall,this study could provide insightful thermal information for the operating condition selection,structure design,and stability assessment of realistic SOFCs combined with their internal reforming process.
文摘Solid oxide fuel cell(SOFC) technology and its status and problems were briefly described.Several topics for furtherresearch and development were proposed.
基金financially supported by the National Natural Science Foundation of China(Grant nos.21376001,21576028 and 21506012)。
文摘Carbon-fueled solid oxide fuel cells(CF-SOFCs)can electrochemically convert the chemical energy in carbon into electricity,which demonstrate both superior electrical efficiency and fuel utilisation compared to all other types of fuel cells.However,using solid carbon as the fuel of SOFCs also faces some challenges,the fluid mobility and reactive activity of carbon-based fuels are much lower than those of gaseous fuels.Therefore,the anode reaction kinetics plays a crucial role in determining the electrochemical performance of CF-SOFCs.Herein,the progress of various anodes in CF-SOFCs is reviewed from the perspective of material compositions,electrochemical performance and microstructures.Challenges faced in developing high performance anodes for CF-SOFCs are also discussed.
基金financially supported by the National Natural Science Foundation of China(Grants Nos.51302135 and 51678291)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20190965)+1 种基金the Research Project of Nanjing Institute of Technology(Grant No.YKJ201435)the Australian Research Council(ARC)Discovery Early Career Researcher Award DE180100773。
文摘Biomass,a source of renewable energy,represents an effective substitute to fossil fuels.Gasification is a process that organics are thermochemically converted into valuable gaseous products(e.g.biogas).In this work,the catalytic test demonstrated that the biogas produced from biomass gasification mainly consists of H2,CH4,CO,and CO2,which were then be used as the fuel for solid oxide fuel cell(SOFC).Planar SOFCs were fabricated and adopted.The steam reforming of biogas was carried out at the anode of a SOFC to obtain a hydrogen-rich fuel.The performance of the SOFCs operating on generated biogas was investigated by I-V polarization and electrochemical impedance spectra characterizations.An excellent cell performance was obtained,for example,the peak power density of the SOFC reached 1391 mW·cm-2 at 750℃when the generated biogas was used as the fuel.Furthermore,the SOFC fuelled by simulated biogas delivered a very stable operation.
基金supported by the Thailand Research Fund(TRG 5680051)
文摘The cell performance and temperature gradient of a tubular solid oxide fuel cell with indirect internal reformer (IIR-SOFC) fuelled by natural gas, containing a typical catalytic packed-bed reformer, a catalytic coated wall reformer, a catalytic annular reformer, and a novel catalytic annular-coated wall reformer were investigated with an aim to determine the most efficient internal reformer system. Among the four reformer designs, IIR-SOFC containing an annular-coated wall reformer exhibited the highest performance in terms of cell power density (0.67 W.cm 2) and electrical efficiency (68%) with an acceptable temperature gradient and a moderate pressure drop across the reformer (3.53 × 10 5 kPa). IIR-SOFC with an annular-coated wall reformer was then studied over a range of operating conditions: inlet fuel temperature, operating pressure, steam to carbon (S : C) ratio, gas flow pattern (co-flow and counter-flow pattern), and natural gas compositions. The simulation results showed that the temperature gradient across the reformer could not be decreased using a lower fuel inlet temperature (1223 K-1173 K) and both the power density and electrical efficiency of the cell also decreased by lowering fuel inlet temperature. Operating in higher pressure mode (1-10 bar) improved the temperature gradient and cell performance. Increasing the S : C ratio from 2 : 1 to 4:1 could decrease the temperature drop across the reformer but also decrease the cell performance. The average temperature gradient was higher and smoother in IIR-SOFC under a co-flow pattern than that under a counter-flow pattern, leading to lower overpotential and higher cell performance. Natural gas compositions significantly affected the cell performance and temperature gradient. Natural gas containing lower methane content provided smoother temperature gradient in the system but showed lower power density and electrical efficiency.
基金partly supported by Japan Society for the Promotion of Science (JSPS) Postdoctoral Fellowships for Research in Japan (P22370)by Key Project of Jiangsu Province (BE2022029) in China。
文摘Accurate prediction of performance degradation in complex systems such as solid oxide fuel cells is crucial for expediting technological advancements.However,significant challenges still persist due to limited comprehension of degradation mechanisms and difficulties in acquiring in-situ features.In this study,we propose an effective approach that integrates long short-term memory(LSTM) neural network and dynamic electrochemical impedance spectroscopy(DEIS).This integrated approach enables precise prediction of future evolutions in both current-voltage and EIS features using historical testing data,without prior knowledge of degradation mechanisms.For short-term predictions spanning hundreds of hours,our approach achieves a prediction accuracy exceeding 0.99,showcasing promising prospects for diagnostic applications.Additionally,for long-term predictions spanning thousands of hours,we quantitatively determine the significance of each degradation mechanism,which is crucial for enhancing cell durability.Moreover,our proposed approach demonstrates satisfactory predictive ability in both time and frequency domains,offering the potential to reduce EIS testing time by more than half.
基金Supported by the Natural Science Foundation of Guangdong Province (No. 031424).
文摘A solid state H2S/air electrochemical cell having the configuration of H2S, (MoS2+NiS+Ag)/YSZ/Pt,air has been examined with different H2S flow rates and concentrations at atmospheric pressure and 750-850℃.Performance of the fuel cell was dependent on anode compartment H2S flow rate and concentration. The cell open-circuit voltage increased with increasing H2S flow rate. It was found that increasing both H2S flow rate and H2S concentration improved current-voltage and power density performance. This is resulted from improved gas diffusion in anode and increased concentration of anodic electroactive species. Operation at elevated H2S concentration improved the cell performance at a given gas flow rate. However, as low as 5% H2S in gas mixture can also be utilized as fuel feed to cells. Highest current and power densities, 1750mA·cm^-2 and 200mW·cm^-2,are obtained with pure H2S flow rate of 50 ml·min^-1 and air flow rate of 100ml·min^-1 at 850℃.
基金Project supported by National Natural Science Foundation of China (90510006)
文摘Glass-ceramic materials were developed as a sealant in the solid oxide fuel cell (SOFC) in the temperature range of 800 -850 ℃. The glass materials were based on the glass and glass-ceramic in the BaO-CaO-Al2O3-SiO2-La2O3-B2O3 system. The thermal expansion coefficient (TEC) decreased with lower Ba^2+ content and higher Ca^2+ content, but the glass transition temperature and crystallization temperature increased greatly with an increase in Ca^2+ content and a decrease in Ba^2+ content, when the other components in the sealant were invariable. The TEC of the sealant with Ba^2+ content of 25.4% was 10.8 × 10^-6 K^- 1(temperature range from 25 to 850℃), and its softening temperature was 950 ℃. The TEC of the sealant accorded well with that of La0.9Sr0.1Ga0.5Mg0.2o3- 6(LSGM) with a mismatch of only 3%. The sealant had superior stability and compatibility with the LSGM electrolyte during the process of operation in SOFC. The weight loss of the sealant with Ba^2+ content of 25.4% was approfimately zero after heat-treated at 800℃ for 500 h in H2 and O2 atmosphere, respectively.
文摘A simulation model was developed to analyze the steady state and transient operation of a tubular solid oxide fuel cell. The model covers both the electrochemical and the heat transfer models. The electrochemical model deals with the Nernst potential, ohmic polarization, activation polarization, and concentration polarization, while the heat transfer model concerns the heat transfer by conduction, convection and radiation. The numerical results show that the ohmic loss is the dominant one among the three polarizations in a cathode-supported solid oxide fuel cell and in the middle part of a solid oxide fuel cell the temperature is higher than those at both the ends. When the inlet temperature and the flow rates of the fuel and the oxidant are kept constantly, the temperature of the solid structure of the cell will increase due to the increase of power output of the cell from the initial state to the new one.
基金supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2012013782)research funds of Changwon National University in 20122013
文摘A Gd-doped ceria(GDC) buffer layer is required between a conventional yttria-stabilized zirconia(YSZ) electrolyte and a La-Sr-Co-Fe-O3(LSCF) cathode to prevent their chemical reaction. In this study,the effect of varying the conditions for fabricating the GDC buffer layer, such as sintering temperature and amount of sintering aid, on the solid oxide fuel cell(SOFC) performance was investigated. A finer GDC powder(i.e., ultra-high surface area), a higher sintering temperature(1290℃), and a larger amount of sintering aid(12%) resulted in improved densification of the buffer layer; however, the electrochemical performance of an anode-supported cell containing this GDC buffer layer was poor. These conflicting results are attributed to the formation of(Zr, Ce)O2 and/or excess cobalt grain boundaries(GBs) at higher sintering temperatures with a large amount of sintering aid(i.e., cobalt oxide). A cell comprising of a cobalt-free GDC buffer layer, which was fabricated using a low-temperature process, had lower cell resistance and higher stability. The results indicate that electrochemical performance and stability of SOFCs strongly depend on fabrication conditions for the GDC buffer layer.
基金Project supported by the National Natural Science Foundation of China (50204007)the Foundation of Yunnan Province (2005PY01-33)
文摘La1-xSrxGa1-yMgyO3-δ (LSGM) electrolyte, La1-xSrxCr1-yMnyO3-δ (LSCM) anode and La1-xSrxFe1-yMnyO3-δ (LSFM) cathode materials were all synthesized by glycine-nitrate process (GNP). The microstructure and characteristics of LSGM, LSCM and LSFM were tested via X-ray diffraction(XRD), scanning electron microcopy (SEM), A C impedance and four-probe direct current techniques. XRD shows that pure perovskite phase LSGM electrolyte and electrode (LSCM anode and LSFM cathode) materials were prepared after being sintered at 1400 ℃ for 20 h and at 1000 ℃ for 5 h, respectively. The max conductivities of LSGM (ionic conductivity), LSCM (total conductivity) and LSFM (total conductivity) materials are 0.02, 10, 16 S·cm-1 in the air below 850 ℃, respectively. The conductivity of LSCM becomes smaller when the atmosphere changes from air to pure hydrogen at the same temperature and it decreases with the temperature like metal. The porous and LSGM-based LSCM anode and LSFM cathode films were prepared by screen printing method, and the sintering temperatures for them were 1300 and 1250 ℃, respectively. LSGM and electrode (LSCM and LSFM) materials have good thermal and chemical compatibility.
文摘Ceria-based heterostructure composite(CHC)has become a new stream to develop advanced low-temperature(300–600°C)solid oxide fuel cells(LTSOFCs)with excellent power outputs at 1000 mW cm−2 level.The state-ofthe-art ceria–carbonate or ceria–semiconductor heterostructure composites have made the CHC systems significantly contribute to both fundamental and applied science researches of LTSOFCs;however,a deep scientific understanding to achieve excellent fuel cell performance and high superionic conduction is still missing,which may hinder its wide application and commercialization.This review aims to establish a new fundamental strategy for superionic conduction of the CHC materials and relevant LTSOFCs.This involves energy band and built-in-field assisting superionic conduction,highlighting coupling effect among the ionic transfer,band structure and alignment impact.Furthermore,theories of ceria–carbonate,e.g.,space charge and multi-ion conduction,as well as new scientific understanding are discussed and presented for functional CHC materials.