Recent Achievements of NEDO Durability Project with an Emphasis on Correlation Between Cathode Overpotential and Ohmic Loss

作者：Harumi Yokokawa, Y. Hori, T. Shigehisa, Mineharu Suzuki, Shuichi Inoue, Toshihide Suto, Kazuo Tomida, Megumi Shimazu, Akira Kawakami, Hirofumi Sumi, Makoto Ohmori, N. Mori, T. Iha, Katsuhiko Yamaji, Haruo Kishimoto, Katherine Develos-Bagarinao, Kazunari Sasaki, Shunsuke Taniguchi, ‪Tatsuya Kawada, Mayu Muramatsu, Kenjiro Terada, Koichi Eguchi, Toshiaki Matsui, Hiroshi Iwai, Masashi Kishimoto, Naoki Shikazono, Yoshihiro Mugikura, Tohru Yamamoto, Masahiro Yoshikawa, Kenji Yasumoto, Koichiro Asano, Yoshio Matsuzaki, Shinji Amaha, Takaaki Somekawa · 发表于：Fuel Cells · 年份：2017 · DOI：10.1002/fuce.201600186 · 被引用次数：50 · 研究领域：Advancements in Solid Oxide Fuel Cells、Electronic and Structural Properties of Oxides、Molten salt chemistry and electrochemical processes

Abstract Long‐term performance testes by CRIEPI (Central Research Institute for Electric Power Industry) on six industrial stacks have revealed an interesting correlation between cathode polarization loss and ohmic loss. To make clear the physicochemical meaning of this correlation, detailed analyses were made on the conductivity degradation of YSZ electrolyte in button cells and then on the ohmic losses in the industrial cells in terms of time constants which are determined from speed of the tetragonal transformation through the Y diffusion from the cubic phase to the tetragonal phase. In some cases, shorter time constants (faster degradations) were detected than those expected from the two‐time‐constant (with and without NiO reduction effects) model, suggesting that additional ohmic losses after subtracting the contribution from the tetragonal transformation must be caused from other sources such as cathode‐degradation inducing effects. Main cathode degradations can be ascribed to sulfur poisoning due to contamination in air in the CRIEPI test site. An important feature was extracted as this cathode degradations became more severe when the gadolinium‐doped ceria (GDC) interlayers were fabricated into dense film. Plausible mechanisms for cathode degradations were proposed based on the Sr/Co depletion on surface of lanthanum strontium cobalt ferrite (LSFC) in the active area. Peculiar cathode degradations found in stacks are interpreted in term of changes in surface concentra...