Yang Gene, Nam Sang-Hoon, Han Gina, Fang Nicholas X, Lee Dongkyu
Department of Mechanical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States.
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
ACS Appl Mater Interfaces. 2023 Nov 1;15(43):50427-50436. doi: 10.1021/acsami.3c07115. Epub 2023 Oct 19.
Fast oxygen reduction reaction (ORR) at the cathode is a key requirement for the realization of low-temperature solid oxide fuel cells (SOFCs). While the design of three-dimensional (3D) structures has emerged as a new and promising approach to improving the electrochemical performance of SOFC cathodes, achieving versatile structures and structural stability is still challenging. In this study, we demonstrate a novel architectural design for a superior cathode with fast ORR activity. By employing a completely new fabrication process comprising a 3D printing technique and pulsed laser deposition (PLD), we design 3D LaSrCoO (LSC) micro-nano structures with the desired shape. 3D-printed yttria-stabilized ZrO (YSZ) microstructures significantly increase the ratio of surface area to volume while maintaining suitable ionic conductivity comparable to that of single-crystalline YSZ substrates. Scanning electron microscopy and energy dispersive X-ray microanalysis reveal the formation of crack- or void-free YSZ microstructures and the uniform deposition of LSC films by PLD on the YSZ microstructures. The 3D LSC micro-nano structures show significantly enhanced oxygen surface exchange coefficients () extracted from electrical conductivity relaxation (ECR) measurements by up to 3 orders of magnitude relative to the bulk LSC. Furthermore, electrochemical impedance spectroscopy measurements verify the values from ECR and no directional difference in the measured ORR activity depending on the shape of 3D microstructures. The dramatic enhancement of the ORR activity of LSC is attributed to the increased film surface areas resulting from the 3D YSZ microstructures.
阴极处快速的氧还原反应（ORR）是实现低温固体氧化物燃料电池（SOFC）的关键要求。虽然三维（3D）结构的设计已成为提高SOFC阴极电化学性能的一种新的且有前景的方法，但实现通用结构和结构稳定性仍然具有挑战性。在本研究中，我们展示了一种用于具有快速ORR活性的优异阴极的新颖架构设计。通过采用包括3D打印技术和脉冲激光沉积（PLD）的全新制造工艺，我们设计出具有所需形状的3D LaSrCoO（LSC）微纳结构。3D打印的氧化钇稳定氧化锆（YSZ）微结构显著增加了表面积与体积之比，同时保持了与单晶YSZ衬底相当的合适离子电导率。扫描电子显微镜和能量色散X射线微分析揭示了无裂纹或无孔隙的YSZ微结构的形成以及PLD在YSZ微结构上LSC薄膜的均匀沉积。相对于块状LSC，通过电导率弛豫（ECR）测量提取的3D LSC微纳结构的氧表面交换系数（）显著提高了多达3个数量级。此外，电化学阻抗谱测量验证了ECR得到的值，并且所测量的ORR活性没有因3D微结构的形状而产生的方向性差异。LSC的ORR活性的显著增强归因于3D YSZ微结构导致的薄膜表面积增加。
