Effect of MgO and Fe2O3 dual sintering aids on the microstructure and electrochemical performance of the solid state Gd0.2Ce0.8O2-δ electrolyte in intermediate-temperature solid oxide fuel cells

Qingwen Liang; Ping Tang; Jing Zhou; Jinghe Bai; Dan Tian; Xiaofei Zhu; Defeng Zhou; Ning Wang; Wenfu Yan

doi:10.3389/fchem.2022.991922

Effect of MgO and Fe₂O₃ dual sintering aids on the microstructure and electrochemical performance of the solid state Gd_0.2Ce_0.8O_2-δ electrolyte in intermediate-temperature solid oxide fuel cells

Front Chem. 2022 Sep 27:10:991922. doi: 10.3389/fchem.2022.991922. eCollection 2022.

Authors

Qingwen Liang^{1

2}, Ping Tang¹, Jing Zhou¹, Jinghe Bai¹, Dan Tian³, Xiaofei Zhu¹, Defeng Zhou¹, Ning Wang^{2

4}, Wenfu Yan⁵

Affiliations

¹ School of Chemistry and Life Science, Changchun University of Technology, Changchun, China.
² Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
³ College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, China.
⁴ Shenzhen Institute of Advanced Electronic Materials, Shenzhen, China.
⁵ State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, China.

Abstract

Solid state electrolytes have been intensively studied in the solid oxide fuel cells (SOFCs). The aim of this work is to investigate the effects of MgO and Fe₂O₃ dual sintering aids on the microstructure and electrochemical properties of solid state Gd_0.2Ce_0.8O_2-δ (GDC) electrolytes, which are prepared by a sol-gel method with MgO and Fe₂O₃ addition to the GDC system. It is found that the addition of MgO and Fe₂O₃ can reduce the sintering temperature, increase densification and decrease the grain boundary resistance of the electrolyte. The 2 mol% MgO and 2 mol% Fe₂O₃ co-doped GDC (GDC-MF) exhibits the highest grain boundary conductivity. At 400°C, the grain boundary conductivity and total conductivity of GDC-MF are 15.89 times and 5.56 times higher than those of GDC. The oxygen reduction reaction (ORR) rate at the electrolyte/cathode interface of GDC-MF is 47 % higher than that of GDC. Furthermore, the peak power density of a single cell supported by GDC-MF is 0.45 W cm^-2 at 700°C, 36.7% higher than that of GDC. Therefore, the GDC-MF should be a promising electrolyte material for intermediate-temperature solid oxide fuel cells (IT-SOFCs).

Keywords: Gd0.2Ce0.8O2-δ (GDC); electrolyte; ionic conductivity; sintering aid; solid oxide fuel cells.