| Solid oxide fuel cell(SOFC)is an all-solid-state chemical power generation device,which can convert chemical energy stored in fuels and oxidants into electrical energy directly and efficiently at medium and high temperatures.SOFC has a variety advantages including all solid state,modular assembly,environment friendly,wide fuel adaptability and high energy conversion efficiency.Menwhile,a great number of hydrocarbon fuels can be used in the SOFC,such as hydrogen,carbon monoxide,natural gas,liquefied gas,coal gas,and biomass gas.The traditional nickel-based anode SOFC uses hydrocarbon as a fuel while the anode has serious carbon deposits and poor resistance to sulfur poisoning,resulting in battery performance degradation and unsatisfied long-term stability.Symmetrical Solid Oxide Fuel Cells(SSOFC)not only simplify the battery preparation process,but also reduce the possible thermal stress between the electrode and the electrolyte interface.The problems that carbon deposition and sulfur poisoning of the anode can be solved by switching the gas path.This article takes SSOFC as the train of thought,uses perovskite materials with simple structure and low cost as the research object to explore a suitable SSOFC electrode material system.The main contents are as follows:Taking Sm0.9Pr0.1FeO3-?(SPF)electrode material as the research object,which is stable in a reduction atmosphere.Phase,thermal expansion and electrochemical properties studied systematically as well.Moreover,YSZ acts as the electrolyte to build a single battery SPF|YSZ|SPF and the battery output performance was evaluated by a self-assembled battery test system.The results show that:(1)The SPF perovskite mineral phase has no change in hydrogen atmosphere,SPF and YSZ do not interact with each other under the high temperature air atmosphere and present good chemical and phase stability.(2)At 800 ?,the polarization resistances of SPF in air and hydrogen atmosphere are 0.15 ?.cm2 and 15.80 ?.cm2,respectively,showing excellent ORR and HOR activities.(3)The cell SPF | YSZ | SPF,with hydrogen(3%H2O)was used as a fuel,the peak power density in 800? of 168 mW.cm-2.It shows that SPF is a promising candidate for SSOFC electrode.High-catalytic activity Ba0.5Sr0.5Co0.2Fe0.7Mo0.1O3-?(BSCFM)electrode material was obtained after Mo doping Ba0.5Sr0.5Co0.2Fe0.8O3-?(BSCF).Single-cells BSCF | GDC| YSZ | GDC | BSCF and BSCFM | GDC | YSZ | GDC | BSCFM were constructed by BSCF and BSCFM as SSOFC electrode materials,YSZ as electrolyte and GDC as transition layer.Verify the possibility of becoming a candidate for SSOFC.The results show:(1).BSCFM has pure cubic perovskite structure and acceptable stability in a reduction atmosphere.Mo doping can greatly improve the thermal stability of the sample.After doping,it is more suitable for working at lower temperatures.(2)Mo doping significantly enhances the catalytic performance of ORR and HOR of BSCF.(3)The peak power density and polarization impedance of the symmetrical cell BSCF | GDC |YSZ | GDC | BSCF at 800 ? with hydrogen(3%H2O)as fuel are 233 mW.cm-2,0.129?.cm2.Under the same conditions,for the battery BSCFM | GDC | YSZ | GDC|BSCFM are 418 mW.cm-2,0.128?.cm2,respectively.(4)The cell BSCFM | GDC | YSZ| GDC | BSCFM can work stably at a constant voltage of 0.7V at 700 ? for 115 hours.This indicates that Ba0.5Sr0.5Co0.2Fe0.7Mo0.1O3-?(BSCFM)can be effcient material for SSOFC electrodes.Pr0.5A0.5FeO3-?(A=Ca,Sr,Ba)electrode material doped with alkaline earth metal at the A site was taken as the research object.The possibility of using three electrode materials Pr0.5Ca0.5FeO3-?(PCF),Pr0.5Ca0.5FeO3-?(PSF)and Pr0.5Ca0.5FeO3-?(PBF)as SSOFC electrode materials investigated in different aspects,such as phase,conductivity and polarization.With YSZ as the electrolyte and GDC as the transition layer,the output performance of the single cell PCF | GDC | YSZ | GDC | PCF,PSF | GDC | YSZ | GDC| PSF and PBF | GDC | YSZ | GDC | PBF were tested.The results show that:(1)PSF and PBF are pure cubic perovskite structures,while PCF has an orthorhombic structure.Further,the stability order of the three materials in the reduced state are:PBF>PCF>PSF.(2)the conductivity changes of the three electrode materials in air are consistent,the interface polarization resistance of PSF in air and hydrogen is the smallest,and the catalytic activity is the highest.For HOR,the catalytic activity sequence:PSF>PCF>PBF,For ORR is PSF>PBF>PCF.(3)Symmetric cells PCF | GDC | YSZ | GDC | PCF,PSF | GDC | YSZ | GDC | PSF and PBF | GDC | YSZ | GDC | PBF,using humid hydrogen as fuel,the peak power density at 800? is 366.40 mW/cm2,502.10 mW/cm2,464.54 mW/cm2,respectively.The relationship between the polarization activity of the three cells is PSF>PBF>PCF.This demonstrates that the three electrode materials have potential as SSOFC electrode.Figure[37]table[5]reference[109]... |
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