Amorphous-cathode-route towards low temperature SOFC
Amorphous-cathode-route towards low temperature SOFC
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DOI：
10.1039/c7se00606c
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发表时间：
2018-04-01
影响因子：
5.6
通讯作者：
Skinner, Stephen J.
中科院分区：
文献类型：
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作者：
Cavallaro, Andrea;Pramana, Stevin S.;Skinner, Stephen J.
降低固体氧化物燃料电池(SOFC)器件的工作温度是限制该技术产业化突破的主要挑战之一。在这项研究中，我们探索了一种使用非晶态阴极材料制备电极的新方法。采用脉冲激光沉积技术，在不同温度下在硅衬底上沉积了La0.8Sr0.2CoO3-Delta致密薄膜。根据沉积温度的不同，可以得到织构的多晶膜或非晶膜。同位素交换深度剖面实验表明，非晶态薄膜的氧扩散系数相对于晶态材料增加了4倍以上，并且伴随着表面交换系数的增加。观察到非晶态和晶态样品的表面化学成分没有差异。值得注意的是，即使用Van Der Pauw方法测量的电子电导表明非晶态材料的电导率降低了，阴极本身的整体催化性能也没有受到影响。这一发现表明，限速步骤是氧的迁移率，非晶态阴极表面的局部电子电导足以保持其催化性能。还对不同的阴极材料进行了测试，以证明非晶-阴极路线的更广泛的适用性。
Lowering the operating temperature of solid oxide fuel cell (SOFC) devices is one of the major challenges limiting the industrial breakthrough of this technology. In this study we explore a novel approach to electrode preparation employing amorphous cathode materials. La0.8Sr0.2CoO3-delta dense films have been deposited at different temperatures using pulsed laser deposition on silicon substrates. Depending on the deposition temperature, textured polycrystalline or amorphous films have been obtained. Isotope exchange depth profiling experiments reveal that the oxygen diffusion coefficient of the amorphous film increased more than four times with respect to the crystalline materials and was accompanied by an increase of the surface exchange coefficient. No differences in the surface chemical composition between amorphous and crystalline samples were observed. Remarkably, even if the electronic conductivities measured by the Van Der Pauw method indicate that the conductivity of the amorphous material was reduced, the overall catalytic properties of the cathode itself were not affected. This finding suggests that the rate limiting step is the oxygen mobility and that the local electronic conductivity in the amorphous cathode surface is enough to preserve its catalytic properties. Different cathode materials have also been tested to prove the more general applicability of the amorphous-cathode route.