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

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/cm(2) and 121 mW/cm(2) at 800 degrees C in H-2 and CH4, respectively.

Automated summary

The study investigates microstructural changes in Ni-SDC cermet anodes using EBSD, highlighting the impact of grain size, distribution, and synthesis methods on performance. Results show that Ni-SDC from GNP outperforms ball-milled samples due to differences in TPB density and phase connectivity, affecting mechanical and electrical conductivity. The presence of sufficient porosity in GNP-made samples eliminates the need for a pore former, emphasizing the importance of TPB length and distribution in optimizing performance. A single cell using GNP-prepared Ni-SDC exhibited a maximum power density of 227 mW/cm(2) in H-2 and 121 mW/cm(2) in CH4 at 800 degrees C.