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A novel liquid-phase synthesis strategy is demonstrated for the preparation of the Nb-containing ceramic oxide SrCo 0.9 Nb 0.1 O 3-δ (SCN). In comparison with the traditional solid-state reaction (SSR) method, the liquid-phase synthesis route offers a couple of advantages, including a lower phase formation temperature and a smaller particle size of the SCN materials that are beneficial for applications as proton-conducting fuel cell cathode. With BaCe 0.4 Zr 0.4 Y 0.2 O 3-δ (BCZY442) as the electrolyte and the SCN synthesized in this work as the cathode, a proton-conducting solid oxide fuel cell (SOFC) shows a peak power density of 348 mW cm −2 at 700 °C, significantly higher than that of a SOFC fabricated with SCN cathode prepared using the SSR method, which can only deliver 204 mW cm −2 at the same temperature. Additionally, this new synthesis strategy allows impregnation of Sr 2+ , Co 3+ and Nb 5+ on the solid backbone in aqueous solution, further improving cell performance to reach a peak power density of 488 mW cm −2 at 700 °C. [ABSTRACT FROM AUTHOR]

The electrospinning technique was employed to prepare the La 0.5 Sr 0.5 Mn 0.875 Zn 0.125 O 3-δ (LSMZn) cathode for proton-conducting solid oxide fuel cells (H–SOFCs). Although the fiber structure can be obtained with the electrospinning technique for the LSMZn precursor, the fiber structure disappeared after the calcination procedure, leading to the formation of fine LSMZn nano-powders. It was found that the electrospun LSMZn can reach a pure phase after firing at 1100 °C, whereas the traditional sol-gel prepared LSMZn required a calcination temperature of 1150 °C. Furthermore, the electrospun LSMZn had a smaller particle size and richer oxygen vacancy than the traditional sol-gel LSMZn. First-principles calculations indicated that the oxygen vacancy-rich surface promoted the cathode reaction. The H–SOFC using the single-phase electrospun LSMZn generated a power density of 1122 mW cm−2 at 700 °C. The performance was not only larger than the sol-gel LSMZn cell reported in this study but also larger than previous H–SOFCs using the single-phase Mn-based cathodes, suggesting the electrospinning technique was an effective method to produce high-performing cathodes for H–SOFCs. [ABSTRACT FROM AUTHOR]

A single-step co-firing process is employed to fabricate solid oxide fuel cells (SOFCs) with an Sm-doped CeO 2 (SDC) electrolyte, aiming to simplify the SOFC fabrication procedure. Complete tri layer green cells are co-fired in a single step at different fabrication temperatures, and the co-firing temperature significantly influences the cell microstructure and thus influences its performance. Electrochemical investigations indicate that the cell resistance, including the ohmic and polarization resistance, varies with the co-firing temperatures used and leads to a different cell power output. Although the cell polarization resistance follows the rule that higher firing temperatures lead to higher polarization resistance values, the cell ohmic resistance does not follow the expectation that the cell fired at 1200 °C gives the largest ohmic resistance. The morphology analysis reveals the mechanism behind this phenomenon. The best cell performance is obtained by co-firing the cell at 1000 °C, reaching 401 mW cm−2 at 700 °C. [ABSTRACT FROM AUTHOR]

A Pr-doping strategy was used to improve traditional strontium-doped lanthanum ferrite oxides for proton-conducting solid oxide fuel cells (SOFCs). Three different samples, La 0.5 Sr 0.5 FeO 3- δ , La 0.25 Pr 0.25 Sr 0.5 FeO 3- δ , and Pr 0.5 Sr 0.5 FeO 3- δ ,were successfully prepared. The Pr content was shown to have an obvious influence on the hydration ability of the materials. Hydration was improved at higher Pr-contents, suggesting a promising cathode performance. However, the improved hydration ability did not always lead to an increased fuel cell performance, and it was found that the fuel cell performed best when an appropriate Pr-doping amount was used that resulted in a good compromise between protonic and oxygen-ion conduction. As a result, the optimized composition La 0.25 Pr 025 Sr 0.5 FeO 3- δ generated a high peak power density of 616 mW cm−2 and a low polarization resistance of 0.09 at Ω cm2 at 700 °C, which is an encouraging performance for a traditional cathode material. [ABSTRACT FROM AUTHOR]

BaZr 0.8 Y 0.2 O 3-δ (BZY20) is found to react with Pt at high temperatures, although Pt is generally regarded as an inert material that prevents its reaction with many materials even at high temperatures. The reaction between BZY20 with Pt is difficult to be confirmed by X-ray diffraction (XRD) analysis as no observable secondary phase can be detected even after high-temperature treatment. However, the obvious color change of the fired BZY20 powder implies the potential reaction. Therefore, transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDS) and X-ray photoelectron spectroscopy (XPS) techniques are used to have an insightful analysis of the material. TEM-EDS result indicates that there is an existence of Pt element in the BZY20 powder after firing, suggesting a Pt diffusion into the BZY20 lattice. XPS analysis results further confirm the content of Pt4+ and Pt2+ in the BZY20 powder after firing and the content of Pt4+ increases with the increase of firing temperatures, and the increase of Pt4+ content lowers the O1s binding energy, which might be beneficial for the proton migration. [ABSTRACT FROM AUTHOR]

In this study, we prepared a Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3- δ (BSCF) cathode layer for proton-conducting solid oxide fuel cells using microwave sintering. Unlike traditional sintering, which is carried out at 1000 °C for a few hours, the microwave sintering method allows the BSCF cathode layer to adhere well with the electrolyte layer after sintering at 900 °C for 10 min. This strategy helps the cathode layer maintain a microstructure favourable for cathode reactions and mitigate the potential diffusion of elements between it and the BaZr 0.1 Ce 0.7 Y 0.2 O 3-δ electrolyte, leading to improved cell resistance. The cell with the BSCF cathode layer sintered by the microwave method has a power output of 0.96 W cm-2 at 700 °C, while the power output for the cell with a conventionally sintered cathode is 0.33 W cm-2. [ABSTRACT FROM AUTHOR]