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Abstract: A high In-dopant level BaCeO3 material was used as an electrolyte for a proton-conducting solid oxide fuel cell (SOFC). Indium behaved as an ideal dopant for BaCeO3, which improved both the chemical stability and sinterability for BaCeO3 greatly. The anode supported BaCe0.7In0.3O3−δ (BCI30) membrane reached dense after sintering at 1100°C, much lower than the sintering temperature for other BaCeO3-based materials. Additionally, the BCI30 membrane showed adequate chemical stability against CO2 compared with the traditional rare earth doped BaCeO3. The BCI30-based fuel cell also showed a reasonable cell performance and a good long-term stability under the operating condition. Besides, the LaSr3Co1.5Fe1.5O10−δ (LSCF) was also evaluated as a potential cathode candidate for a proton-conducting SOFC. [Copyright &y& Elsevier]

Different transition metals are employed to tune the Y-doped BaZrO 3 proton conductor, resulting in the new BaZr 0.125 Y 0.125 M 0.75 O 3 (M = Cu, Mn, Ni, Zn, Co, and Fe) compositions as cathodes for proton-conducting solid oxide fuel cells. Only Co and Fe dopants can yield pure phases, whereas the use of other dopants results in impurities. Further experimental studies and first-principles calculations show that using Fe dopant has some advantages over Co-doped material, such as increased oxygen vacancies, lower proton migration energy barriers, and faster proton and oxygen diffusion kinetics. The fuel cell employing the BaZr 0.125 Y 0.125 Fe 0.75 O 3 (BZYFe) cathode has a larger fuel cell output than the fuel cell using the BaZr 0.125 Y 0.125 Co 0.75 O 3 (BZYCo) cathode. Furthermore, the CO 2 adsorption energy on the BZYFe surface is larger than that at the BZYCo surface, indicating that BZYFe has significantly better chemical stability than BZYCo. The long-term stability of the fuel cell demonstrates that the fuel cell with the BZYCo cathode is degrading. In contrast, the BZYFe cell has good operating stability. Given its phase purity, fuel cell performance, and stability, the Fe element is an appropriate dopant for altering BZY and creating a new cathode. • BaZr 0.125 Y 0.125 M 0.75 O 3 (M = Cu, Mn, Ni, Zn, Co, and Fe) were prepared. • Only Co and Fe dopants can generate pure phases. • BaZr 0.125 Y 0.125 Co 0.75 O 3 and BaZr 0.125 Y 0.125 Fe 0.75 O 3 cathodes yielded similar cell performance. • The cell using BaZr 0.125 Y 0.125 Fe 0.75 O 3 cathode showed better operational stability. [ABSTRACT FROM AUTHOR]

A Sr-deficiency approach is utilized to adjust the composition of the standard Sr 2-x Fe 1.5 Mo 0.25 Sc 0.25 O 6 (SFMS) material, with the goal of improving the performance of the SFMS cathode in proton-conducting solid oxide fuel cells (H–SOFCs). The Sr-deficiency concentration is restricted to 10% at the Sr site, and an increase in Sr-deficiency leads to the formation of more oxygen vacancies. However, the presence of increased oxygen vacancies does not consistently enhance the diffusion capabilities of charge carriers. The excess of oxygen vacancies impedes the movement of oxygen and protons. The optimal oxygen and proton transport capabilities are achieved when the Sr-deficiency level is set at 5%. Specifically, this is observed in the compound Sr 1.9 Fe 1.5 Mo 0.25 Sc 0.25 O 6 (S1.9FMS). The enhanced oxygen and proton diffusion kinetics enable H–SOFCs to achieve exceptional performance when employing the S1.9FMS cathode, reaching a power density of 1709 mW cm−2 at 700 °C with a low polarization resistance of 0.023 Ω cm2. The fuel cell's output exceeds that of many previously reported H–SOFCs. Furthermore, the fuel cell utilizing the S1.9FMS cathode not only exhibits excellent fuel cell performance but also maintains reliable operational stability. This indicates that employing the Sr-deficiency technique with an appropriate level of deficiency is a successful approach to enhance the cathode performance for H–SOFCs. • A Sr-deficiency approach was used to tailor Sr 2-x Fe 1.5 Mo 0.25 Sc 0.25 O 6 (SFMS). • The Sr-deficient SFMS showed improved oxygen and proton diffusion kinetics. • A high fuel cell performance was obtained with the Sr 1.9 Fe 1.5 Mo 0.25 Sc 0.25 O 6 cathode. • Good stability was retained for the Sr 1.9 Fe 1.5 Mo 0.25 Sc 0.25 O 6 cathode. [ABSTRACT FROM AUTHOR]

LaNi 0.5 Fe 0.5 O 3-δ (LNF) is a viable option for the cathode of solid oxide fuel cells (SOFCs), however, its performance in proton-conducting SOFCs (H–SOFCs) is not sufficient. In this work, an Sc-doped method to increase the cathode performance of conventional LNF for H–SOFCs is proposed. Although the Sc cation can be doped at the Ni site or the Fe site in LNF, which led to the formation of pure phase materials, first-principles calculations indicate that the formation of the LaNi 0.4 Sc 0.1 Fe 0.5 O 3-δ (LNSF) material has more advantages than the formation of the LaNi 0.5 Fe 0.4 Sc 0.1 O 3-δ (LNFS) material, even though the same Sc-doping level is employed. Compared to Sc-free LNF, LNSF provides superior fuel cell performance. At 700 °C, the LNSF cell generates a peak power density of 1534 mW cm−2, double that of the LNF cell. In addition, employing the LNSF cathode reduces the cell's polarization resistance, indicating that the Sc-doping strategy paired with selecting the doping site is an effective method for reusing LNF in high-performance H–SOFCs. • Sc cations can be doped at the Fe or Ni sites in LaNi 0.5 Fe 0.5 O 3-δ (LNF). • The site occupation at the Ni site shows advantages compared with that at the Fe site. • Sc-doped LNF shows better performance than the Sc-free one. • The performance of the cell using LaNi 0.4 Sc 0.1 Fe 0.5 O 3-δ is better. [ABSTRACT FROM AUTHOR]

A new honeycomb-shaped La 0·5 Sr 0·5 Fe 0·9 P 0·1 O 3-δ (LSFP) material has been proposed as a cathode for proton-conducting solid oxide fuel cells (H–SOFCs). Compared with conventional LSFP, the honeycomb-shaped does not change the crystal structure or the electronic structure of the material but offers a much higher surface area. The unique honeycomb structure allows the easier diffusion of air and H 2 O evaporations in the cathode, thus benefiting the application of LSFP as a cathode for LSFP. The honeycomb LSFP cathode's fuel cell shows a peak power density of 1474 mW cm−2 at 700 °C, which is higher than the conventional LSFP cell. In addition, the fuel cell performance is also the highest ever reported for H–SOFCs based on the Sr-doped LaFeO 3 (LSF) cathodes, making a new life for the first-generation LSF cathode for H–SOFCs. The distribution of relaxation times (DRT) analysis for the cell reveals that the honeycomb-shaped cathode improves the oxygen reduction reaction (ORR) at the cathode, thus improving the cathode kinetics. • A honeycomb-shaped La 0·5 Sr 0·5 Fe 0·9 P 0·1 O 3-δ (LSFP) material has been prepared. • The honeycomb structure improved the surface area. • The cell using the honeycomb LSFP cathode showed higher fuel cell performance. • The performance enhancement mechanism was studied. [ABSTRACT FROM AUTHOR]

Abstract: The cermet consisting of electronic conductor Ni and proton conductor La2Ce2O7 (LDC) shows good chemical stability but poor hydrogen permeability. In order to improve the hydrogen permeability, novel Ni–La2−x Sm x Ce2O7 (x =0, 0.025, 0.05, 0.075, 0.1 and 0.2) cermets were developed for hydrogen separation. The results show that Sm element doping of LDC can affect the rate of hydrogen permeation, with Ni–La1.95Sm0.05Ce2O7 possessing the highest hydrogen permeation fluxes. [Copyright &y& Elsevier]