The Impact of Sintering Atmosphere and Temperature on the Phase Evolution of High Surface Area LSCF Prepared by In Situ Carbon Templating
The Impact of Sintering Atmosphere and Temperature on the Phase Evolution of High Surface Area LSCF Prepared by In Situ Carbon Templating
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DOI：
10.1149/1945-7111/abf062
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发表时间：
2021-03
影响因子：
3.9
通讯作者：
S. Muhoza;Thomas H. Taylor;Xueyan Song;M. Gross
中科院分区：
文献类型：
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作者：
S. Muhoza;Thomas H. Taylor;Xueyan Song;M. Gross
研究了原位碳模板法制备的镧锶钴铁氧体（LSCF）在1000 ~ 1200 ℃的热化学稳定性。该方法在传统的固体氧化物燃料电池（SOFC）烧结温度下通过原位产生碳模板并随后通过在700 ℃下氧化除去模板来产生高表面积陶瓷。氩气处理的样品产生无定形碳模板，而氮气倾向于形成石墨碳。在氧化步骤之前，与氩（9-17 nm）相比，氮样品包含更大的La 2 O 3微晶（22-40 nm）。在氧化后，氩样品产生纯的LSCF相，表面积在21-29 m2· g-1范围内，而氮样品含有大量杂质。这表明在惰性处理期间形成的La 2 O 3微晶的尺寸限制了产生纯LSCF相的能力。将包含通过模板法产生的纳米LSCF电极的对称电池与直接在空气中烧结的电池进行比较。阻抗结果表明，纳米LSCF电池和在空气中处理的电池分别由界面电荷转移电阻和气体扩散主导。结果绘制了在传统烧结温度下制备和集成高表面积，纳米结构的LSCF到SOFC电极的条件。讨论了改善纳米LSCF电极界面电阻的策略。
The thermochemical stability of lanthanum strontium cobalt ferrite (LSCF) processed between 1000 C–1200 C via the in situ carbon templating method was studied. This method generates high surface area ceramics at traditional solid oxide fuel cell (SOFC) sintering temperatures by generating a carbon template in situ and subsequently removing the template by oxidation at 700 C. Argon processed samples produced an amorphous carbon template, whereas nitrogen tended to form graphitic carbon. Prior to the oxidation step, nitrogen samples comprised larger La 2 O 3 crystallites (22–40 nm) compared to argon (9–17 nm). Upon oxidation, argon samples resulted in a pure LSCF phase with surface areas in the 21–29 m 2· g− 1 range, whereas nitrogen samples contained significant impurities. This demonstrates that the size of La 2 O 3 crystallites formed during inert processing limited the ability to produce a pure LSCF phase. Symmetrical cells comprising nano-LSCF electrodes generated by the templating method were compared to cells sintered directly in air. Impedance results suggest that nano-LSCF cells and cells processed in air were dominated by interfacial charge transfer resistance and gas diffusion, respectively. The results map out conditions for preparing and integrating high surface area, nanostructured LSCF into SOFC electrodes at traditional sintering temperatures. Strategies for improving the interfacial resistance of nano-LSCF electrodes are discussed.