Xin Zhao,Wen Liu,Jian Zhang,Xuanlin Lu,Jiaxuan Chen,Tianqi Shao,Jinpeng Zhang,Yicheng Zhao,Yongdan Li
Rational design of the electrode microstructure is an important strategy to improve the performance of solid oxide fuel cells. Electrospinning is an effective approach for the production of electrode materials with a nanofiber microstructure, which provides straight and continuous pathways for ionic and electronic conduction. In this study, the self-assembled La0.7Sr0.3Fe0.9Ni0.1O3−δ (LSFN)–Ce0.8Sm0.2O2−δ (SDC) composite with a hollow nanofiber structure is synthesized as the cathode material of protonic ceramic fuel cells (PCFCs) through a coaxial electrospinning process. LSFN and SDC are both distributed uniformly in the composite cathode. Compared with composite cathodes prepared through electrospinning with solid and core–shell nanofiber structures, the hollow-fiber LSFN–SDC cathode shows a higher specific surface area and provides more channels for gas diffusion, both of which are beneficial for the oxygen reduction reaction. The LSFN–SDC composite cathode with the hollow fiber structure exhibits the lowest polarization resistance of 0.035 Ω cm2 at 700 °C. A PCFC with that cathode shows a maximum power density of 1598 mW cm–2 and a promising short-term stability at 700 °C.
Xin Zhao,Jian Zhang,Xuanlin Lu,Wen Liu,Jiaxuan Chen,Yicheng Zhao,Yongdan Li
Self-assembled La 0.7 Sr 0.3 Fe 0.9 Ni 0.1 O 3-δ -Ce 0.8 Sm 0.2 O 1.9-δ (LSFN-SDC) composite cathode with a three-dimensionally ordered macroporous (3DOM) structure is synthesized using poly(methyl methacrylate) as the template for protonic ceramic fuel cells . The LSFN and SDC phases both distribute uniformly in the cathode. The SDC phase reduces the thickness of the walls of the 3DOM structure and thus hinders the bulk conduction of electrons. SDC also decreases the specific surface area and the surface oxygen reactivity of the cathode, leading to the suppression of the adsorption and dissociation of O 2 . However, the SDC phase provides the conduction pathway for oxygen ions and enlarges three phase boundary consequently, which facilitates the charge transfer steps. The thickness of the walls and the specific surface area of the composite cathode are both increased with the rise of the concentration of the nitrate precursor solution, resulting in the acceleration of the cathode process. Nevertheless, an excessive precursor concentration leads to the destroy of the 3DOM structure. The 3DOM composite cathode exhibits the lowest R p of 0.039 Ω cm 2 , and a single cell with that cathode shows maximum power density of 1484 mW cm −2 at 700 °C. The cell exhibits a short-term stability of 120 h at 700 °C without noticeable degradation.
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