管式ScSZ电解质支撑固体氧化物燃料电池的电化学性能研究及其串联验证OA

High operating temperatures often cause thermal mechanical stress in anode-supported tubular solid oxide fuel cells(SOFCs)using traditional yttrium-stabilized zirconia(YSZ)electrolytes.To overcome this issue,this study developed a new type of tubular SOFC supported by a scandium-stabilized zirconia(ScSZ)electrolyte.High-density ScSZ electrolyte tubes were prepared using cold isostatic pressing and coreless grinding techniques and then sintered at high temperatures to achieve a thickness of approximately 220 μm.The Ag-ScSZ|ScSZ|Ag-ScSZ single cells were successfully prepared by coating a Ag-ScSZ slurry on the ScSZ electrolyte and then sintering it at a high temperature to form a symmetrical electrode to improve interface compatibility and electrochemical performance.Phase analysis of the ScSZ electrolyte and Ag-ScSZ electrode was carried out by X-ray diffraction.The ScSZ electrolyte retains its fluorite cubic structure,while no secondary phases appears in Ag-ScSZ,providing a solid foundation for the high performance of tubular SOFCs.Scanning electron microscopy and energy-dispersive spectroscopy were used to analyze the structure and elemental distribution of the single-cell cross section.Dense layers of the ScSZ electrolyte and a well-distributed Ag-ScSZ electrode were observed,which create excellent pathways for ion conduction.Notably,the ScSZ electrolyte-supported symmetric tubular single cell showed significantly better electrochemical performance than the traditional YSZ electrolyte-supported symmetric single cell,verifying the excellent ionic conductivity of the ScSZ electrolyte compared to the YSZ electrolyte.The power density of the ScSZ electrolyte-supported SOFC at 850℃increased by approximately 87%compared to that of the YSZ electrolyte-supported SOFC.Meanwhile,the Ohmic and polarization resistances of the ScSZ electrolyte-supported SOFC decreased by 17%and 93%,respectively.This cell can also achieve a power density of approximately 244 mW/cm2 at 900℃and stably output the current density of 300 mA/cm2 without significant performance degradation after 35 hours of constant voltage discharge at 0.7 V.These findings demonstrate the excellent electrochemical stability of the ScSZ electrolyte-supported tubular single cells.In addition,to improve electrochemical performance,a basic dual-tube series stack was constructed by connecting two ScSZ electrolyte-supported single cells in series using a spiral current collecting method.This stack achieved a two-fold voltage increase and a power enhancement of 1.9 times,demonstrating its potential in stack integration.This study provides experimental evidence for the future development of tubular electrolyte-supported SOFCs.