以NH3以及3％ H2O增湿的H2、CH4、C3H8和煤炭地下气化(underground coal gasification,UCG)气为燃料,用最小Gibbs自由能法计算平衡气体组分和理论电池电动势,并测试在NiO-GDC ‖ GDC ‖Ba0.9Co0.7Fe0.2Nb0.1O3-δ (B0.9CFN)阳极支撑固体氧化物燃料电池(SOFC)中的电池开路电压、电池性能和长期稳定性.结果表明,以上述气体作燃料的SOFC热力学计算理论电动势均高于1.05 V,而由于GDC电解质在还原气氛下存在电子电导,导致碳氢燃料在NiO-GDC‖GDC‖B0.9 CFN阳极支撑电池中的开路电压略小.中低温下,碳氢燃料相对缓慢的动力学过程和GDC电解质快速的氧离子传输速率,使得以UCG气、CH4和C3H8为燃料的电池实际积炭比理论预测少.以UCG气为燃料的SOFC在500、550、600和650℃的最高功率密度分别高达0.151、0.299、0.537和0.729W· cm-2,在0.6V恒压放电120 h后性能没有明显衰减,且阳极表面无积炭产生,表明直接UCG气SOFC具有广阔的应用前景.%The equilibrium species and theoretical electromotive force of cells fed with NH3 and 3％ H2O humidified H2,CH4,C3H8 and underground coal gasification (UCG) gas on the basis of minimum Gibbs free energy were calculated,whilst the open circuit voltage (OCV),V-I characteristics and long-term stability of NiO-GDC ‖ GDC ‖ Ba0.9 Co0.7 Fe0.2 Nb0.1O3 δ (B0.9 CFN) anode-supported cells operated in above five fuels were evaluated.The results showed that direct utilization of hydrocarbon fuels in anode could achieve a desirable electromotive force (EMF) no less than 1.05 V,while the OCV for ceria-based cells was comparatively poorer due to the presence of electronic conductivity.Besides,the synergy effect between stagnant kinetics of hydrocarbons reforming and the relatively sufficient O2-supply due to fast migration of oxide ions suppressed carbon deposition at low operating temperatures for ceria-based SOFC.Furthermore,the UCG gas fed cell exhibited peak power densities as high as 0.151,0.2 9 9,0.5 3 7 and 0.729 W · cm-2,respectively at 500,550,600 and 650℃,and showed no evident performance decay and carbon deposition on anode after discharging at 600℃ under a constant voltage of 0.6 V for 120 h,thereby demonstrating UCG gas is a promising fuel for direct utilization in SOFC.
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