Hybrid Electrochemical Deposition Route for the Facile Nanofabrication of a Cr-Poisoning-Tolerant La(Ni,Fe)O3-δ Cathode for Solid Oxide Fuel Cells

Ahmad Shaur; Saeed Ur Rehman; Hye-Sung Kim; Rak-Hyun Song; Tak-Hyoung Lim; Jong-Eun Hong; Seok-Joo Park; Seung-Bok Lee

doi:10.1021/acsami.9b17807

Hybrid Electrochemical Deposition Route for the Facile Nanofabrication of a Cr-Poisoning-Tolerant La(Ni,Fe)O_3-δ Cathode for Solid Oxide Fuel Cells

ACS Appl Mater Interfaces. 2020 Feb 5;12(5):5730-5738. doi: 10.1021/acsami.9b17807. Epub 2020 Jan 22.

Authors

Ahmad Shaur^{1

2}, Saeed Ur Rehman¹, Hye-Sung Kim¹, Rak-Hyun Song^{1

2}, Tak-Hyoung Lim^{1

2}, Jong-Eun Hong¹, Seok-Joo Park^{1

2}, Seung-Bok Lee^{1

2}

Affiliations

¹ Fuel Cell Laboratory, New and Renewable Energy Research Division , Korea Institute of Energy Research , 152 Gajeong-ro , Yuseong-gu, Daejeon 34129 , Republic of Korea.
² Department of Advanced Energy and Technology , University of Science and Technology , 217 Gajeong-ro , Yuseong-gu, Daejeon 34113 , Republic of Korea.

PMID: 31918549
DOI: 10.1021/acsami.9b17807

Abstract

Cr poisoning of cathode materials is one of the main degradation issues hampering the operation of solid oxide fuel cells (SOFCs). To overcome this shortcoming, LaNi_0.6Fe_0.4O_3-δ (LNF) has been developed as an alternative cathode material owing to its superior chemical stability in Cr environments. In this study, we develop a hybrid electrochemical deposition technique to fabricate a nanostructured LNF-gadolinium-doped ceria (GDC) (n-LNF-GDC) cathode with enhanced active reaction sites for the oxygen reduction reaction. For this purpose, Fe and Ni cations are co-deposited onto an electrically conductive carbon nanotube-modified GDC backbone by electroplating, whereas La cations are successively deposited through a chemically assisted electrodeposition method. The proposed method involves a low-temperature (900 °C) calcination step of electrodeposited cations, which avoids the need of fabricating a GDC diffusion barrier layer which is otherwise needed to avoid the formation of insulating phases (e.g., La₂Zr₂O₇) when fabricating by conventional high-temperature (≥1000 °C) sintering. Scanning electron microscopy images reveal a unique nanofibrous structure of n-LNF-GDC, which is believed to play an instrumental role in enhancing the electrochemical characteristics by increasing the active triple-phase boundaries. An anode-supported SOFC with the n-LNF-GDC cathode showed the superior performance of 0.984 W cm^-2 at an intermediate temperature of 750 °C as compared to the power densities of 0.495 and 0.874 W cm^-2 produced by LNF-GDC and state-of-the-art La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF)-GDC composite cathodes fabricated by conventional sintering. A short-term accelerated Cr-poisoning durability test indicated good electrochemical stability of n-LNF-GDC, whereas LSCF exhibited severe degradation. The electrochemically engineered nanostructured n-LNF-GDC can serve as an effective cathode for SOFCs to achieve high performance and long-term durability.

Keywords: Cr-tolerant cathode; LaNi0.6Fe0.4O3−δ; electrodeposition; nanofabrication; solid oxide fuel cell.