- 著者
- Hiroyuki SHIMADA Toshiaki YAMAGUCHI Hirofumi SUMI Yuki YAMAGUCHI Katsuhiro NOMURA
- 出版者
- The Ceramic Society of Japan
- 雑誌
- Journal of the Ceramic Society of Japan (ISSN:18820743)
- 巻号頁・発行日
- vol.125, no.4, pp.257-261, 2017-04-01 (Released:2017-04-03)
- 参考文献数
- 28
- 被引用文献数
- 9 10
Perovskite-type mixed protonic and oxide ionic conductors for electrolyte material of solid oxide fuel cells were investigated, focusing on BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb) due to its high ionic conductivity and chemical stability. BZCYYb and NiO-added BZCYYb were evaluated using electrolyte-supported cell (ESC) and anode-supported cell (ASC) samples. 2 wt.% NiO was solid solute into the BZCYYb, resulting in improvement in the sinterability and thermal-expansion behavior. The addition of NiO, however, lead to the deterioration of cell performance. Compared with the ESC, power density of the ASC was much higher due to thin electrolyte, whereas its open-circuit voltage (OCV) was lower. This is due to Ni diffusion from the NiO–BZCYYb anode into the BZCYYb electrolyte during high-temperature co-sintering process at 1350°C. From the results of OCV measurements, 0–2 wt.% NiO was considered to be dissolved in the BZCYYb electrolyte of the ASC, suggesting that controlling Ni diffusion during co-sintering process is essential to achieve higher-performance ASCs using BZCYYb.
- 著者
- Tomohiro ISHIYAMA Haruo KISHIMOTO Katherine DEVELOS-BAGARINAO Katsuhiko YAMAJI Toshiaki YAMAGUCHI Yoshinobu FUJISHIRO
- 出版者
- The Ceramic Society of Japan
- 雑誌
- Journal of the Ceramic Society of Japan (ISSN:18820743)
- 巻号頁・発行日
- vol.125, no.4, pp.247-251, 2017-04-01 (Released:2017-04-03)
- 参考文献数
- 23
- 被引用文献数
- 9 10
The perovskite-type proton conductor with the composition of BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb) has been reported to exhibit the highest proton conductivity among proton conductors. However, cerate-based perovskite materials such as BZCYYb are also known to react with carbon dioxide which causes phase decomposition through the formation of barium carbonate. This is a significant issue because chemical stability is an important property to enable these materials to be utilized for fuel cell applications. In this study, the chemical stability of BZCYYb was investigated in CO2 or CO2 + H2 atmosphere, with or without nickel addition as sintering aid. Some nickel addition is assumed to occur from nickel diffusion in anode-support-type fuel cells. The enhancement of reactivity with carbon dioxide species by adding nickel into BZCYYb was attributed to barium enrichment at grain boundary regions and the formation of an impurity phase of Ba(Y(1−x)Ybx)2NiO5. Moreover, different decomposition reactions depending on the atmosphere have been inferred. In a pure CO2 atmosphere, barium carbonate formation occurred without appearance of the CeO2-based phase, in other words, without decomposition of the perovskite phase. On the other hand, in hydrogen-containing CO2 atmosphere, both the barium carbonate and CeO2-based phase were observed.