Theoretical and Experimental Investigations on K‐doped SrCo_0.9Nb_0.1O_3‐δ as a Promising Cathode for Proton‐Conducting Solid Oxide Fuel Cells

Abstract

Improving proton conduction in cathodes is regarded as one of the most effective methods to accelerate the sluggish proton‐involved oxygen reduction reaction (P‐ORR) for proton‐conducting solid oxide fuel cells (P‐SOFCs). In this work, K+ dopant was used to improve the proton uptake and migration ability of SrCo0.9Nb0.1O3‐δ (SCN). K+‐doped SCN (KSCN) demonstrated great potential to be a promising cathode for P‐SOFCs. Density functional theory calculations suggested that doping with K+ led to more oxygen vacancies and more negative values of hydration enthalpy, which was helpful for the improvement of proton concentration. Importantly, the proton migration barriers could be depressed, benefiting proton conduction. Electrochemical investigations signified that the cell using KSCN cathode had a peak power density of 967 mW cm−2 at 700 °C, about 54.1 % higher than that using a SCN cathode. This research highlights the K+‐doping strategy to improve electrochemical performance of cathodes for P‐SOFCs.

Attempted preparation of La 0.5Ba 0.5MnO 3− δ leading to an in-situ formation of manganate nanocomposites as a cathode for proton-conducting solid oxide fuel cells

“…for the nominal La0.7Ba0.3MnO3 in DFT calculations. This method is widely used in first-principles calculations [41][42][43]. Observable accumulations of charges (electrons) at the interface suggest that the oxygen atoms at the interface are more ionized, hence aiding the creation of Vo.…”

A synergistic dual-phase air electrode enables ultrahigh and durable performance of reversible proton ceramic electrochemical cells

“…This suggests that the hexagonal phase possesses a higher B-site average valence, which may be responsible for the remarkable thermal reduction of H-BSCF at high temperatures that creates oxygen vacancies and promotes hydration, as further veri ed later 20,26,39 . At room temperature, cubic C-BSCF has the lowest Co and Fe valences, which implies the presence of more oxygen vacancies and facilitates the acceleration of the ORR rate at the air electrode surface 40,41 . Furthermore, XPS analysis was also used to reveal the oxidation states of Co and Fe in different samples.…”

Surface Self‐Assembly Protonation Triggering Triple‐Conductive Heterostructure with Highly Enhanced Oxygen Reduction for Protonic Ceramic Fuel Cells

“…Materials Synthesis: Powders of the parent PrBaCo 2 O 5+δ and derivative zirconium doped PrBaCo 2−x Zr x O 5+δ series, abbreviated as PBC, PBCZ04, PBCZ08, and PBCZ12 for x = 0, 0.04, 0.08, and 0.12, respectively, were synthesized via a citric acid combustion method. [56] Stoichiometric amounts of Pr(NO 3 ) 3 •6H 2 O (AR, ≥99.5%), Ba(NO 3 ) 2 (AR, ≥99.5%), Co(NO 3 ) 2 •6H 2 O (AR, ≥99.5%), and Zr(NO 3 ) 4 •5H 2 O (AR, ≥99.5%) were completely dissolved in dilute nitric acid (AR, ≥99.5%). Subsequently, citric acid (AR, ≥99.5%) and ethylenediaminetetraacetic acid (EDTA, AR, ≥99.5%) were added as complexing agents, with the molar ratio of 1:1.5:1 for total metal ions, citric acid, and EDTA.…”