A Stable and Efficient Cathode for Fluorine‐Containing Proton‐Conducting Solid Oxide Fuel Cells

Abstract

Substitution of anions such as F and Cl can effectively improve the stability of proton-conducting electrolytes at no expense to proton conduction. However, during operation, F and Cl in electrolytes can transfer to the cathodes, which reduces the stability of the electrolytes. In this work, F -doped Ba Sr Co Fe O [Ba Sr Co Fe O F (F-BSCF)] was prepared as a potential cathode for proton-conducting solid oxide fuel cells with BaCe Sm F O electrolyte. The incorporation of F in the cathode depressed F diffusion from the electrolyte and improved the stability of button cells. Temperature-changing X-ray photoelectron spectroscopy and electronic conductivity relaxation results demonstrated that the incorporation of F enhanced the oxygen incorporation kinetics at intermediate temperatures and improved the cathode catalytic performance. Moreover, a button cell prepared with this novel cathode was stable for 270 h at a current density of 300 mA cm and 700 °C, which was much superior than those containing a BSCF cathode.

Tailoring cations in a perovskite cathode for proton-conducting solid oxide fuel cells with high performance

“…Despite the fact that making direct comparisons for SOFC tests is difficult due to the variability of many parameters, the cell using a BKSCF cathode, as reported in this study, showed a much larger power output than most of H-SOFCs using a BSCF-based cathode reported previously, 18,24,[55][56][57][58][59] which suggests that K-doping into BSCF can enhance the cathode catalytic activity, thus allowing a fuel cell performance improvement. The only exception is reported by An et al 60 In their study, proton-conducting SOFCs using single-phase BSCF cathode were fabricated.…”

Theoretical and Experimental Investigations on K‐doped SrCo0.9Nb0.1O3‐δ as a Promising Cathode for Proton‐Conducting Solid Oxide Fuel Cells

“…Moreover, the decreased activation energy for D chem may be ascribed to the weakened metal−oxygen bond due to the larger cell parameters as well as longer metal−oxide bonds, which facilitate the transport of oxygen ions [15] …”

La-doped Ba0.5Sr0.5Co0.8Fe0.2O3- d as Cathode for Protonic-Conducting Solid Oxide Fuel Cells with Enhanced Structure Stability

“…Ba0.5Sr0.5Co0.8Fe0.2O3- (BSCF) is regarded as an excellent oxygen reduction reaction electrocatalyst due to its superior oxygen transport properties (11). As we previously reported, the oxygen chemical bulk diffusion coefficient, Dchem, and chemical oxygen surface exchange coefficient, kchem, of BSCF at 700  C are 2*10 -5 cm 2 S -1 and 4*10 -4 cm S -1 , respectively (12). Both the bulk diffusion coefficient and the surface exchange coefficient of BSCF are about one order of magnitude higher than those of classic electrocatalyst La0.6Sr0.4Co0.8Fe0.2O3- (LSCF) at the same temperature: 6.4*10 -6 cm 2 S -1 for kchem and 1.3*10 -5 cm S -1 for Dchem, respectively (13), and are comparable with those of PrBaCo2O5+ which is the state-of-the-art electrocatalyst for PCFCs cathodes (1*10 -5 cm -2 S -1 for Dchem and 1*10 -4 cm S -1 for kchem, respectively) (2,14).…”

“…However, the strong interaction between lanthanum and oxygen ions may affect the hybridization of oxygen ions with Co/Fe (29), which has an important effect on the conductivity and other properties of BSCF. Oxygen transport properties are important for proton conducting cathode materials, as they will affect the catalytic activity toward oxygen reduction reaction (ORR), the recovery of surface active sites, and so on (12). In this work, the electrical conductivity relaxation (ECR) technique is used to explore the effect of lanthanum on the oxygen transport properties.…”