Utilization of natural silica from rice husk ash to improve electrical conductivity of SDC-based it-SOFC electrolyte

Azmi, Mohd Azham and Jaidi, Zolhafizi and Abd Rahman, Hamimah and Abdul Rahman, Nurul Farhana and Ahmad, Nor Suzyliana and Wan Mahmood, Wan Hasrulnizzam and Abdul Salaam, Hadi and Mohd Shapri, Ahmad Husni (2026) Utilization of natural silica from rice husk ash to improve electrical conductivity of SDC-based it-SOFC electrolyte. Malaysian Journal of Microscopy, 22 (1). pp. 197-210. ISSN 1823-7010

Text 0107312062026944303291.pdf Download (1MB)

Abstract

Solid oxide fuel cells (SOFCs) rely on electrolytes with high ionic conductivity and thermal stability, especially for intermediate-temperature operations (500–700 °C). Yttria-stabilized zirconia (YSZ), the conventional SOFC electrolyte, requires high operating temperatures, which leads to thermal mismatch, interfacial degradation, and other performance issues. Samarium-doped ceria (SDC) is a promising alternative due to its superior ionic conductivity at lower temperatures. However, SDC still faces challenges in achieving full densification and minimal porosity without elevated sintering temperatures. This study explores the incorporation of natural silica derived from rice husk ash (RHASiO₂) as an eco-friendly sintering aid to enhance the structural and electrochemical performance of SDC electrolytes. RHASiO₂ was calcined at 700 °C and combined with commercial SDC powder in various weight percentages (0 %–3 %) using dry ball milling. The mixtures were uniaxially pressed into pellets and sintered at 1200 °C. Thermogravimetric analysis (TGA) showed that RHASiO₂ improved thermal stability by reducing weight loss during intermediate and final degradation phases. The microstructure and morphology were characterized using scanning electron microscopy (SEM), while porosity was quantified through image analysis using ImageJ software. The results revealed a decreasing trend in porosity with increasing RHASiO₂ content, reaching the lowest value of 4.58 % in the SDC3.0 sample. Electrochemical impedance spectroscopy (EIS) demonstrated enhanced conductivity and reduced grain boundary resistance for RHASiO₂-modified samples. The highest total ionic conductivity, 2.76 x 10-2 S·cm⁻¹ at 700 °C, was achieved by SDC3.0, which also exhibited the lowest activation energy of 0.768 eV. These results confirm that RHASiO₂ effectively promotes densification and enhances the electrical conductivity of SDC electrolytes, offering a sustainable and low-cost route to improve SOFC performance.

Item Type:	Article
Uncontrolled Keywords:	Samarium-doped ceria (SDC), Rice husk ash silica (RHASiO₂), Solid oxide fuel cell (SOFC), Electrochemical impedance spectroscopy (EIS), Sintering aid
Divisions:	Faculty Of Industrial And Manufacturing Technology And Engineering
Depositing User:	Sabariah Ismail
Date Deposited:	11 Aug 2026 04:11
Last Modified:	11 Aug 2026 04:11
URI:	http://eprints.utem.edu.my/id/eprint/30210
Statistic Details:	View Download Statistic

Actions (login required)

View Item