Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Motooka 744, Nishiku, Fukuoka 819-0395, Japan.
Chemistry. 2012 Sep 10;18(37):11695-702. doi: 10.1002/chem.201200536. Epub 2012 Aug 2.
Self-recovery is one of the most-desirable properties for functional materials. Recently, oxide anodes have attracted significant attention as alternative anode materials for solid-oxide fuel cells (SOFCs) that can overcome reoxidation, deactivation, and coke-deposition. However, the electrical conductivity and surface activity of the most-widely used oxide anodes remain unsatisfactory. Herein, we report the synthesis of an "intelligent oxide anode" that exhibits self-recovery from power-density degradation in the redox cycle by using a Pd-doped La(Sr)Fe-(Mn)O(3) cell as an oxide anode for the SOFCs. We investigated the anodic performance and oxidation-tolerance of the cell by using Pd-doped perovskite as an anode and fairly high maximum power densities of 0.5 and 0.1 W cm(-2) were achieved at 1073 and 873 K, respectively, despite using a 0.3 mm-thick electrolyte. Long-term stability was also examined and the power density was recovered upon exposure of the anode to air. This recovery of the power density can be explained by the formation of Pd nanoparticles, which were self-recovered through reoxidation and reduction. In addition, the self-recovery of the anode by oxidation was confirmed by XRD and SEM and this process was effective for improving the durability of SOFC systems when they were exposed to severe operating conditions.
自恢复性是功能材料最理想的特性之一。最近，氧化物阳极作为固体氧化物燃料电池 (SOFC) 的替代阳极材料引起了极大的关注，因为它可以克服再氧化、失活和积碳问题。然而，最广泛使用的氧化物阳极的电导率和表面活性仍不理想。在此，我们报告了一种“智能氧化物阳极”的合成，该阳极在氧化还原循环中通过使用 Pd 掺杂的 La(Sr)Fe-(Mn)O(3) 电池作为 SOFC 的氧化物阳极来实现自恢复能力，从而自恢复功率密度降低的问题。我们通过使用 Pd 掺杂的钙钛矿作为阳极来研究电池的阳极性能和氧化耐受性，并在 1073 和 873 K 下分别实现了 0.5 和 0.1 W cm(-2) 的相当高的最大功率密度，尽管使用了 0.3 mm 厚的电解质。还对长期稳定性进行了测试，并在将阳极暴露于空气中时恢复了功率密度。这种功率密度的恢复可以通过形成 Pd 纳米颗粒来解释，这些纳米颗粒通过再氧化和还原得到自恢复。此外，通过 XRD 和 SEM 证实了阳极的自氧化恢复，并且当 SOFC 系统暴露于恶劣的操作条件时，该过程有效地提高了其耐久性。
