Superionic Conductivity in Ceria-Based Heterostructure Composites for Low-Temperature Solid Oxide Fuel Cells

Abstract

• Ceria-based heterostructure composite for novel semiconductor-ionic fuel cells. • Superionic conduction at interfaces is associated with the crossover of band structure. • Band alignment/bending resultant built-in field plays a significant role in superionic conduction. ABSTRACT Ceria-based heterostructure composite (CHC) has become a new stream to develop advanced low-temperature (300-600 °C) solid oxide fuel cells (LTSOFCs) with excellent power outputs at 1000 mW cm −2 level. The state-ofthe-art ceria-carbonate or ceria-semiconductor heterostructure composites have made the CHC systems significantly contribute to both fundamental and applied science researches of LTSOFCs; however, a deep scientific understanding to achieve excellent fuel cell performance and high superionic conduction is still missing, which may hinder its wide application and commercialization. This review aims to establish a new fundamental strategy for superionic conduction of the CHC materials and relevant LTSOFCs. This involves energy band and built-in-field assisting superionic conduction, highlighting coupling effect among the ionic transfer, band structure and alignment impact. Furthermore, theories of ceria-carbonate, e.g., space charge and multi-ion conduction, as well as new scientific understanding are discussed and presented for functional CHC materials.

Nanostructured Ceria: Biomolecular Templates and (Bio)applications

“…Nanosized ceria finds a large variety of applications [71], and extensive reviews exist on the topic, especially relevant to catalysis [1] for energy [72,73] and environmental preservation [74] and remediation [75,76]. Therefore, here we will focus on the latest advancements described in the most recent years, with an emphasis on biological applications, for which the use of biomolecular templates for ceria nanostructures' assembly is particularly relevant.…”

Recent Progress in Semiconductor-Ionic Conductor Nanomaterial as a Membrane for Low-Temperature Solid Oxide Fuel Cells

“…In 2011, Zhu et al found that a single layer of the nanocomposite of LiNiZn-based oxide and doped ceria can realize the function of SOFCs which was proven to exhibit an impressive performance [ 37 ]. This new device was firstly named as electrolyte-free fuel cells (EFFCs) [ 37 , 38 ] or single-layer fuel cells (SLFCs) [ 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. Since then, many efforts have been devoted to study this kind of fuel cell in order to understand its working mechanisms, as well as how to utilize the high ionic conductivity [ 46 , 47 , 48 , 49 ].…”

Self-Assembled Triple (H+/O2−/e−) Conducting Nanocomposite of Ba-Co-Ce-Y-O into an Electrolyte for Semiconductor Ionic Fuel Cells

“…Tremendous efforts have been dedicated to reduce the production cost and promote the performance of the cell based on functional materials and the revolutionary design of the structure of SOFCs [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. In recent years, SOFCs based on a ceramic proton conductor–also known as protonic ceramic fuel cells (PCFCs)–have demonstrated outstanding performance.…”

“…At the same time, the new architectures in heterostructure materials with a semiconductor and an ionic conductor yield interesting properties with ionic conduction highways between two-phase interfaces [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. A notable example is CeO 2 /CeO 2-δ core-shell structure, which exhibits a super proton conductivity of 0.16 S cm −1 for the electrolyte at 520 °C [ 11 ].…”