National Synchrotron Radiation Laboratory, University of Science and Technology of China , Hefei 230026, P. R. China.
ACS Appl Mater Interfaces. 2018 Jan 17;10(2):1761-1770. doi: 10.1021/acsami.7b16703. Epub 2018 Jan 5.
Driven by the demand to minimize fluctuation in common renewable energies, reversible solid oxide cells (RSOCs) have drawn increasing attention for they can operate either as fuel cells to produce electricity or as electrolysis cells to store electricity. Unfortunately, development of proton-conducting RSOCs (P-RSOCs) faces a major challenge of poor reliability because of the high content of steam involved in air electrode reactions, which could seriously decay the lifetime of air electrode materials. In this work, a very stable and efficient air electrode, SrEuFeCoO (SEFC) with layer structure, is designed and deployed in P-RSOCs. X-ray diffraction analysis and High-angle annular dark-filed scanning transmission electron microscopy images of SEFC reveal that Sr atoms occupy the center of perovskite slabs, whereas Eu atoms arrange orderly in the rock-salt layer. Such a special structure of SEFC largely depresses its Lewis basicity and therefore its reactivity with steam. Applying the SEFC air electrode, our button switches smoothly between both fuel cell and electrolysis cell (EC) modes with no obvious degradation over a 135 h long-term test under wet H (∼3% HO) and 10% HO-air atmospheres. A record of over 230 h is achieved in the long-term stability test in the EC mode, doubling the longest test that had been previously reported. Besides good stability, SEFC demonstrates great catalytic activity toward air electrode reactions when compared with traditional LaSrCoFeO air electrodes. This research highlights the potential of stable and efficient P-RSOCs as an important part in a sustainable new energy power system.
受最小化常见可再生能源波动需求的驱动，可逆固体氧化物电池 (RSOC) 因其既可作为燃料电池发电，也可作为电解电池储存电力而受到越来越多的关注。不幸的是，质子传导 RSOC (P-RSOC) 的发展面临着一个主要挑战，即由于空气电极反应中涉及大量蒸汽，其可靠性较差，这可能会严重降低空气电极材料的寿命。在这项工作中，设计并部署了具有层状结构的非常稳定和高效的空气电极 SrEuFeCoO (SEFC) 用于 P-RSOC。SEFC 的 X 射线衍射分析和高角度环形暗场扫描透射电子显微镜图像表明，Sr 原子占据钙钛矿片的中心，而 Eu 原子在岩盐层中有序排列。SEFC 的这种特殊结构极大地抑制了其路易斯碱性，从而降低了其与蒸汽的反应性。应用 SEFC 空气电极，我们的纽扣开关在湿 H（∼3% HO）和 10% HO-空气气氛下，经过长达 135 小时的长期测试，在燃料电池和电解池（EC）模式之间平稳切换，没有明显的降解。在 EC 模式下的长期稳定性测试中，实现了超过 230 小时的记录，是之前报道的最长测试时间的两倍。与传统的 LaSrCoFeO 空气电极相比，SEFC 不仅具有良好的稳定性，而且在空气电极反应方面表现出优异的催化活性。这项研究强调了稳定高效的 P-RSOC 作为可持续新能源动力系统的重要组成部分的潜力。
