Boosting the electrochemical performance of micro-tubular solid oxide fuel cell via the microstructure regulation

Herein, a hierarchically oriented porous anode supported micro-tubular solid oxide fuel cell (MT-SOFC) employing a bi-layered electrolyte has been prepared by phase inversion method and evaluated for power generation. The achieved asymmetric anode not only can facilitate the gas transportation through the anode, but also can provide sufficient active sites for hydrogen oxidation. Meanwhile, the bi-layered electrolyte can effectively prevent the formation of a highly resistive zirconate phase between the La_0.6Sr_0.4Co_0.2Fe_0.8O₃ cathode and the yttria-stabilized zirconia (YSZ) electrolyte, while the YSZ electrolyte layer can effectively block the electronic conduction in the Ce_0.8Sm_0.2O_1.9 (SDC) interlayer as well. The morphology of the prepared anode support is examined by the two-dimensional (2D) scanning electron microscopy (SEM) and backscattered electrons analysis, as well as the three-dimensional (3D) X-ray microscopy analysis. Moreover, the 3D microstructure of the anode support is reconstructed, and then a quantitative analysis is performed. Additionally, the microstructure of the bi-layered electrolyte including the interface between YSZ and SDC layer is investigated by SEM and energy-dispersive X-ray spectroscopy. The prepared MT-SOFC exhibits an excellent peak output power density of 0.43, 0.77, 1.19 and 1.79 Wcm⁻² at 650, 700, 750, and 800 ℃, respectively. The excellent cell performance is attributed to the asymmetrical structured anode support with a low tortuosity factor in combination with the sufficient active sites for hydrogen oxidation. Our findings can guide the development of high-performance MT-SOFCs.