Effect of Synthesis Method of Nickel–Samarium-Doped Ceria Anode on Distribution of Triple-Phase Boundary and Electrochemical Performance

Muhammed Ali Shaikh Abdul,Mustafa Anwar,Vadim M Kovrugin,Mun Teng Soo,Ahmad Zubair Yahaya,Andanastuti Muchtar

doi:10.3390/cryst11050513

Abstract

Two-dimensional (2D) electron back scattered diffraction (EBSD) is a powerful tool for microstructural characterization of crystalline materials. EBSD enables visualization and quantification of the effect of synthesis methods on the microstructure of individual grains, thus correlating the microstructure to mechanical and electrical efficiency. Therefore, this work was designed to investigate the microstructural changes that take place in the Ni-SDC cermet anode under different synthesis methods, such as the glycine–nitrate process (GNP) and ball-milling. EBSD results revealed that different grain size and distribution of Ni and SDC phases considerably influenced the performance of the Ni–SDC cermet anodes. The performance of the Ni–SDC cermet anode from GNP was considerably higher than that of Ni-SDC from ball-milling, which is attributed to the triple-phase boundary (TPB) density and phase connectivity. Due to the poor connectivity between the Ni and SDC phases and the development of large Ni and SDC clusters, the Ni-SDC cermet anode formed by ball milling had a lower mechanical and electrical conductivity. Moreover, the Ni–SDC cermet anode sample obtained via GNP possessed sufficient porosity and did not require a pore former. The length and distribution of the active TPB associated with phase connectivity are crucial factors in optimizing the performance of Ni-SDC cermet anode materials. The single cell based on the Ni–SDC composite anode prepared through GNP exhibited a maximum power density of 227 mW/cm2 and 121 mW/cm2 at 800 °C in H2 and CH4, respectively.

Highlights

The XRD results confirmed that no phase changes or any chemical reaction occurred between NiO and SDC during synthesis and calcination
A Nickel oxide–samarium-doped ceria (NiO–SDC) composite anode was synthesized by two different methods, glycine–nitrate process (GNP) and high-speed ball milling
The results demonstrated that using the ball milling technique led to the formation of large

Summary

Introduction

The anode is a dominant component of the SOFC and provides active sites for oxidation of hydrogen by reacting with oxide ions from the solid electrolyte, and facilitating fuel access and product removal [3]. Nickel oxide–samarium-doped ceria (NiO–SDC) composites have been widely explored as a high-performance anode material for intermediate-temperature SOFCs (IT-SOFCs) because of their high hydrogen catalytic activity and internal reformation of hydrocarbon fuels [4]. The combination of NiO and SDC has significantly improved the catalytic activity of the anode toward oxidation hydrogen fuel and promoted excellent internal reformation of hydrocarbon fuels [5]. The performance of NiO-SDC composite anode materials strongly depends on the microstructural properties of the synthesized powders [6]

Methods

Results

Conclusion