Effect of electrolyte thickness manipulation on enhancing carbon deposition resistance of methane‐fueled solid oxide fuel cell

Abstract

Summary Dual‐layer hollow fiber (DLHF) micro‐tubular solid oxide fuel cell (MT‐SOFC) consisting of nickel oxide‐yttria‐stabilized zirconia (NiO‐YSZ) anode/YSZ electrolyte was fabricated via a single‐step phase inversion‐based co‐extrusion/co‐sintering technique in order to investigate the effect of different electrolyte extrusion rates (1‐5 mL min−1) at different sintering temperature (1350°C, 1400°C, and 1450°C) under methane (CH4) condition. The DLHF co‐sintered at 1450°C was chosen as optimum temperature due to the good mechanical strength and gas‐tight property. Meanwhile, 18 to 34 μm of electrolyte thickness was achieved when electrolyte extrusion rate increase from 1 to 5 mL min−1. Power density as high as 0.32 W cm−2 was obtained on the cell with the electrolyte layer of 18 μm in thickness (DLHF1) which is 20% higher than the cell with an electrolyte layer of 34 μm (DLHF5) which was only 0.12 W cm−2 when operated at 850°C. However, DLHF1 had suffered cracking formation that originated from anode site which shortened the stability test duration to only 8 hours of survival under 750°C. While DLHF5 can operate up to 15 hours but an increase in electrolyte thickness had resulted in higher ohmic area‐specific resistance that lowering the power density. Fifty‐seven percent reduction in cell performance was observed under methane condition when compared to the cell that performs using hydrogen gas due to the carbon deposition as proven by Raman spectroscopy and carbon, hydrogen, nitrogen, and sulfur analyzer.

Sol‐gel based copper metallic layer as external anode for microtubular solid oxide fuel cell

“…The low peaks were resulted from the very low content of Cu used. Furthermore, the Cu thickness of 1.36 μm in Cycle 5 was considerably thin compared to the thickness of a typical anode in MT‐SOFC which was 150 μm 28 …”

“…The reduction transition in permeability signifies pore blockage which possibly occurred during deposition of Cu. As shown in, 28 MT-SOFC made via phase inversion was known to induce several types of porosity, ranging from nano-size sponge-like porosity to micron size finger-like projections. 18 Based on Figure 4, the 140 nm size Cu grain might have blocked smaller pores, thus greatly reducing the gas flow.…”

“…It was possible that electrolyte gas tightness was the reason that the performance of the SOFC was lower than other cells in the literature. 10,28 Nonetheless, when compared to the anode with no Cu coating, the performance was found to be improved markedly when coated with Cu at Cycle 5 of deposition.…”

Highly conductive hematite electrolyte for low‐temperature solid oxide fuel cell

“…Many studies have shown that the thickness of the electrolyte attaches tightly to the ohmic impedance. The ohmic resistance can be reduced by adopting a thinner electrolyte 16‐18 . But the excessive reduction of electrolyte thickness will result in a significant decrease in its intensity.…”

“…The ohmic resistance can be reduced by adopting a thinner electrolyte. [16][17][18] But the excessive reduction of electrolyte thickness will result in a significant decrease in its intensity. The polarization resistance of SOFC will increase dramatically when the operating temperature decreases.…”