High-performing and stable non-doped ceria electrolyte with amorphous carbonate coating layer for low-temperature solid oxide fuel cells. (10th October 2021)

• Record Type: Journal Article
• Authors: Akbar, Muhammad; Jin, Bin; Tu, Zhengwen; Gao, Jie; Yousaf, Muhammad; Mushtaq, Naveed; Wang, Xunying; Dong, Wenjing; Wang, Baoyuan; Cai, Yixiao; Xia, Chen
• Is Part Of: Electrochimica acta. Volume 393(2021)
• Publication Date: 2021-10-10
• Subjects: Solid oxide fuel cell -- Electrolyte -- Non-doped CeO2 -- High performance -- Coating layer -- Interfacial conduction; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2021.139067
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: A high-performing and stable non-doped CeO2 was developed for LT-SOFCs. The CeO2 prepared by Na2 CO3 precipitant exhibited higher performance than other two samples prepared by NH4 HCO3 and KOH. An ultra-thin Na2 CO3 coating layer was detected in the high-performing non-doped CeO2 . The coating layer played a crucial role in enabling good stability and high ionic conduction. ABSTRACT: Recent studies have realized fast ionic transport in pure ceria (CeO2 ) via surface conduction without using conventional structural doping, indicating a promising strategy to develop electrolytes for low-temperature solid oxide fuel cells (LT-SOFCs). In this work, to further develop the potential of non-doped ceria, a new CeO2 electrolyte (CeO2 #1) is synthesized through precipitation method by using Na2 CO3 as precipitant for surface modification, and compared with two other CeO2 samples (CeO2 #2 and CeO2 #3) prepared by NH4 HCO3 and KOH precipitants. The CeO2 #1 is found to be composed of ceria and slight amorphous Na2 CO3, while CeO2 #2 and CeO2 #3 contain simplex ceria. When applied in SOFCs, the CeO2 #1 electrolyte achieves attractive fuel cell performance (706 mW cm −2 at 550 °C) with good stability, demonstrably superior to those of CeO2 #2 and CeO2 #3 electrolytes. Further impedance spectra analysis manifests the high proton conductivity of CeO2 #1, and suggests that the electrochemical performance superiority of CeO2 #1 should be ascribed to its micro-structural feature. Subsequent TEM characterization confirms the existence of Na2 CO3 in CeO2 #1 as an ultra-thin coating layer, benefiting from which, the CeO2 can be protected from being reduced by H2 and enable high ionic conductivity by virtue of ceria/carbonate interface. This work thus points out a new type of non-doped ceria electrolytes with different working mechanism from previous studies and indicates a feasible approach to develop high-performing and stable electrolytes for LT-SOFCs. Graphical abstract: Developing a high-performing and stable non-doped ceria electrolyte for low-temperature solid oxide fuel cells by forming amorphous carbonate coating layer. Image, graphical abstract