Mixed-conductive membrane composed of natural hematite and Ni0.8Co0.15Al0.05LiO2-δ for electrolyte layer-free fuel cell

Chen Xia, Muhammad Afzal, Baoyuan Wang, Aslan Soltaninazarlou, Wei Zhang, Yixiao Cai, Bin Zhu*

1Department of Energy Technology, Royal Institute of Technology, Stockholm SE 10044, Sweden

2Hubei Collaborative Innovation Center for Advanced Organic Materials, Faculty of Physics and Electronic Technology, Hubei University, Wuhan, Hubei 430062, China

3Department of Engineering Sciences, Ångström Laboratory, Uppsala University, 751 21 Uppsala, Sweden

Adv. Mater. Lett., 2017, 8 (2), pp 114-121

DOI: 10.5185/amlett.2017.7065

Publication Date (Web): Dec 27, 2016

E-mail: binzhu@kth.se, zhubin@hubu.edu.cn

Abstract


Very recently, natural hematite has been developed as an electrolyte candidate for solid oxide fuel cells (SOFCs), because of its considerable ionic conductivity. In this work, to exploit more practical applications of natural hematite, we report a novel mixed-conductive composite made of natural hematite (α-Fe2O3) and semiconductor Ni0.8Co0.15Al0.05LiO2-δ (NCAL) to act as membrane layer in a new SOFC technology, electrolyte-layer free fuel cell (EFFC). The Hematite-NCAL composite was synthesized directly from natural hematite and commercial NCAL by solid-state blending and high-temperature calcination. The EFFC were constructed into a sandwich architecture with Hematite-NCAL as the membrane and NCAL pasted-Ni foams as the electrodes. Electrochemical impedance spectra (EIS) and direct current (DC) polarization measurements were carried out to investigate the electrical conductivity of the composite. A high ionic conductivity of 0.16 S cm-1 is achieved by the composite at 600 oC with mass ratios of 7:3 (7Hematite: 3NCAL). When operated at low temperatures, the as-designed fuel cell demonstrated superior power densities of 554 mW cm-2 at 600 oC and 342 mW cm-2 at 500 oC. Considering the competitive cost, abundant resource and eco-friendliness of natural hematite, our findings indicate the Hematite-NCAL can be a highly promising candidate for advanced low-temperature SOFC applications.

Keywords

Electrolyte layer-free fuel cell, mixed-conductor, membrane, natural hematite, Ni0.8Co0.15Al0.05LiO2-&delta,

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