Browsing by Author "Wu, Bingxue"

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Achieve a high electrochemical oxidation activity by a self-assembled cermet composite anode with low Ni content for solid oxide fuel cells
(2023-10) Wu, Bingxue; Zhang, Jian; Yang, Zhi; Lu, Xuanlin; Zhao, Xin; Liu, Wen; Chen, Jiaxuan; Zhao, Yicheng; Li, Yongdan
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Ni-based cermets are the most widely used anode materials for solid oxide fuel cells. Reducing the content of Ni is beneficial to anode stability but usually unfavorable for the catalytic activity. In this study, Ni-Ce0.8Sm0.2O2-δ anode with a low Ni content is synthesized through a polymer-directed evaporation-induced self-assembly strategy. Ni distributes evenly in the anode, resulting in an enlarged triple-phase boundary region and improved reactivity of lattice oxygen in the oxide phase. The anode containing 5 wt.% Ni possesses the highest amounts of oxygen vacancies and Ce3+/Ce4+ redox pairs that facilitates the charge transfer process, which is one of the rate-determining steps of anode reaction. Consequently, that anode shows the lowest polarization resistance of 0.014 Ω cm2 at 700 °C, much lower than those of other Ni-based anodes prepared through conventional techniques such as impregnation and solid-mixing. With that anode, a single cell supported by a 480-μm-thick Ce0.8Sm0.2O2-δ electrolyte layer exhibits the maximum power density of 270 mW cm−2 at 700 °C. The anode also shows a promising stability.
Self-assembled La0.6Sr0.4FeO3-δ-La1.2Sr0.8NiO4+δ composite cathode for protonic ceramic fuel cells
(2023-08-01) Yang, Zhi; Zhang, Jian; Wu, Bingxue; Zhao, Xin; Lu, Xuanlin; Zhao, Yicheng; Li, Yongdan
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The oxygen reduction reaction at the cathode is an essential process for protonic ceramic fuel cells. Composite cathode materials are commonly used towards the multiple requirements including high surface oxygen activity as well as sufficient electronic and ionic conductivities. In this study, a cobalt-free composite cathode composed of a perovskite La0.6Sr0.4FeO3-δ phase and a Ruddlesden-Popper La1.2Sr0.8NiO4+δ phase is synthesized with a self-assembly technology. The cathode process is mainly controlled by (I) the reduction of adsorbed oxygen atom to O− on the surface and (II) the migration of O− from the surface into the lattice. The former benefits from the high electrical conductivity of La0.6Sr0.4FeO3-δ, and the latter is accelerated by La1.2Sr0.8NiO4+δ attributed to its superior oxygen activity. The one-pot synthesized composite cathode shows an enhanced synergistic effect due to the uniform distribution of the two phases at the nanoscale. The cathode shows the lowest polarization resistances of 0.055 and 0.095 Ω cm2 at 700 °C in oxygen and air, respectively. The results show that self-assembled La0.6Sr0.4FeO3-δ-La1.2Sr0.8NiO4+δ nanocomposite is a promising cathode material for protonic ceramic fuel cells.