Correlation between hydration properties and electrochemical performances on Ln cation size effect in layered perovskite for protonic ceramic fuel cells  

作　　者：Inhyeok Cho Jiwon Yun Boseok Seong Junseok Kim Sun Hee Choi Ho-Il Ji Sihyuk Choi 

机构地区：[1]Department of Mechanical Engineering,Kumoh National Institute of Technology,Gumi 39177,Gyeongbuk,Republic of Korea [2]Department of Aeronautics,Mechanical and Electronic Convergence Engineering,Kumoh National Institute of Technology,Gumi 39177,Gyeongbuk,Republic of Korea [3]Center for Energy Materials Research,Korea Institute of Science and Technology(KIST),Seoul 02792,Republic of Korea [4]Center for Hydrogen and Fuel Cell Research,Clean Technology Research Division,Korea Institute of Science and Technology(KIST),Seoul 02792,Republic of Korea [5]Department of Energy and Environmental Engineering,University of Science and Technology,Seoul 02792,Republic of Korea [6]Nanomaterials Science and Engineering,Korea University of Science and Technology(UST),KIST Campus,Seoul 02792,Republic of Korea

出　　处：《Journal of Energy Chemistry》2024年第1期1-9,I0001,共10页能源化学（英文版）

基　　金：supported by the National Research Foundation (NRF) grant funded by the Korea government (NRF2022R1C1C1007619, NRF-2021M3H4A1A01002921, NRF2021M3I3A1084292);supported by the KIST Institutional Program (Project No. 2E32592-23-069)。

摘　　要：PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.

关 键 词：Protonic ceramic fuel cell Cathode Triple ionic and electronic conductor Hydration property Proton uptake Gibbs free energy 

分 类 号：O646[理学—物理化学] TM911.4[理学—化学]