Cu ion regulates the stability and oxygen reduction kinetics of Co-based double perovskite as SOFC cathode
Qingyuan Sheng, Yaping Zhang, Xiaofei Zhu, Qiwei Chen, Shangyu Li, Jinghe Bai, Wenfu Yan, Defeng Zhou
Abstract
Enhancing the oxygen reduction catalytic activity and thermal compatibility of cathode materials under intermediate-temperature conditions remains pivotal for advancing the commercialization of solid oxide fuel cells (SOFCs). Therefore, this article regulates the crystal structure of NdBaCo 2 O 5+δ (NBC)-based double perovskite by Cu, replacing Co with a small amount of Cu ions to increase the oxygen vacancy content of the cathode material and reduce the thermal expansion coefficient (TEC) of NBC-based materials, to improve the electric catalytic activity and long-term stability of SOFC. The distribution of relaxation time results confirms that compared with NBC, NdBaCo 1.8 Cu 0.2 O 5+δ (NBCC2) can greatly enhance oxygen's dissociation and adsorption rates. As a symmetrical cell at 650 °C, the area-specific resistance (ASR) of NBCC2 is only 0.067 Ω cm −2 , which is about 40 % of NBC. As the cathode of SOFC, the maximum power density of the NBCC2-based cell reaches 0.67 W cm 2 , which is 1.58 times that of NBC, and Cu doping improves the long-term stability problem caused by the high TEC of Co-based materials. This study provides an effective solution for further enhancing the electrocatalytic activity of Co-based perovskite and addressing stability issues caused by high TEC .