High current density SOFC with heterogenization of porous electrodes

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H02077
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Kyoto University
• Principal Investigator: Iwai Hiroshi 京都大学, 工学研究科, 教授 (00314229)
• Co-Investigator(Kenkyū-buntansha): 岸本 将史 京都大学, 工学研究科, 准教授 (10757636) ; 吉田 英生 京都大学, 工学研究科, 教授 (50166964)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 固体酸化物形燃料電池 / 多孔質電極 / ガス拡散 / 造孔材

Outline of Final Research Achievements

This study focuses on the counter-transport phenomena of hydrogen and steam in the porous fuel electrodes of solid oxide fuel cells. The influence of the discrete existence of relatively large pores formed by the pore-formers in the nanoscale pore structure, where the influence of Knudsen diffusion is strong, was studied by experiment, structural observation and quantification, and numerical analysis. As a result, a total pressure gradient in the direction of the fuel electrode thickness was experimentally demonstrated for the first time. Detailed numerical analysis based on three-dimensional structural data revealed that the relatively large pores caused by the pore-formers are effective for venting steam. On the other hand, hydrogen transport through the large pores tends to be suppressed by the total pressure gradient, while hydrogen transport through the relatively small pores is enhanced in such cases.

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

SOFCの多孔質燃料極において、造孔材由来の大空隙が水素と水蒸気の対向輸送に与える影響を精密な実験、大領域の構造観察とそれに基づく多孔質特徴量の定量化、詳細な数値解析で明らかにした。高効率な発電装置として期待されるSOFCの出力密度向上に資する結果である。また、造孔材による比較的大きなスケールの構造をもつ多孔質に対して、直交型FIB-SEMによる大領域観察を実現し、統計的に有意な多孔質特徴量の定量化に成功した。さらに、代替ガスの採用により、重要な現象を損なわず、かつ実際のSOFCの作動温度よりはるかに低い温度で実施可能な実験手法を確立しSOFCに関する実験的研究において新しい方向性を示した。