Atomic layer deposition of thin-film ceramic electrolytes for high-performance fuel cells

Abstract

This feature article provides a progress review of atomic layer deposition (ALD) for fabrication of oxide-ion as well as proton conducting ceramic fuel cells. A comprehensive analysis of structural, chemical, surface kinetics, and electrochemical characterization results of ALD membranes is also presented. ALD is a surface reaction limited method of depositing conformal, high quality, pinhole-free, uniform thickness nanofilms onto planar or three-dimensional structures. Deposition by one atomic layer at a time also affords unprecedented opportunities to engineer surface termination, to form compositionally graded structures or graded doping, and to synthesize metastable phases that cannot be realized otherwise. Indeed, thin ceramic electrolyte membranes made by ALD exhibit enhanced surface exchange kinetics, reduced ohmic losses, and superior fuel cell performance as high as 1.34 W cm À2 at 500 C. More importantly, ALD offers the opportunity to design and engineer surface structures at the atomic scale targeting improved performance of not only ceramic fuel cells, but also electrochemical sensors, electrolysers and pumps. Joon Hyung Shim is an Assistant Professor of Mechanical Engineering at Korea University (KU) and a Project Manager of Green Manufacturing Research Center (GMRC) at KU. Before joining KU as a faculty, he worked as a postdoctoral researcher at National Renewable Energy Laboratory (NREL) and a fulltime lecturer of Mechanical Engineering at Stanford University. He received the B.S. degree in Mechanical and Aerospace Engineering from Seoul National University in 2002. He also received the M.S. and Ph.D. degree in Mechanical Engineering from Stanford University in 2004 and 2009 respectively. Sangkyun Kang is an executive managing director of Hanchang Industries, where he oversees researches in energy materials. Before joining Hanchang Industries, he worked as a research staff member of Samsung Advanced Institute of Technology. There, he conducted ALD research as the leader of the thin lm ceramic fuel cell project. He

Low-temperature performance of yttria-stabilized zirconia prepared by atomic layer deposition

“…It is noteworthy that SOFCs with ALD YSZ electrolytes outperform similar SOFCs using YSZ films prepared by other thin-film techniques [1,6,12,13]. This enhanced performance has been attributed to two properties: the reduced ohmic loss across the ultrathin membrane when used as a freestanding electrolyte in micro-SOFCs, and the greatly improved surface kinetics of nanocrystalline ALD YSZ films [1,6,12].…”

Colossal resistance switching and band gap modulation in a perovskite nickelate by electron doping

“…Pt also serves as catalyst for hydrogen dissociation. Then a low-temperature proton conductor yttrium-doped barium zirconate (BYZ) is grown on top that serves as a proton reservoir/ conductor to store/transport protons 27 . Above it, yttria-stabilized zirconia (YSZ) is deposited to serve as a gate insulator at device operation temperature.…”

Performance Degradation of Lanthanum Strontium Cobaltite after Surface Modification

“…27 In addition, the self-limiting nature of the ALD ensures that the modification material is uniformly formed on the porous substrate. 28 Yu et al concluded that ALD-added CeO x and SrO had a detrimental effect on the performance of various cathodes. 27 In other studies, ALD Al 2 O 3 was intentionally applied to cathodes in order to examine the relationship between geometric blocking and the performance.…”