Browsing by Author "Zhao, Pengcheng"

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Fabrication of Proton Conducting Electrochemical Half-cell Based on Perovskite Structure Material
(University of Waterloo, 2024-09-16) Zhao, Pengcheng
The rising concerns about 𝐶𝑂2 emissions from industrial processes and fossil fuel combustion are driving the development of clean energy sources. Among these, hydrogen energy stands out as an efficient carrier with high storage capacity and minimal environmental impact. This thesis focuses on the fabrication of a solid oxide electrochemical half-cell (SOC) based on proton-conducting materials in a perovskite structure, which can be used for hydrogen generation or utilization. The primary material used is Barium Zirconium Cerium Yttrium Oxide (BZCY) due to its proton conductivity, chemical stability, and mechanical strength under varying conditions. In this work, several nanomaterials synthesis methods were utilized, including sol-gel and combustion processes, to achieve high-purity BZCY172 material with the desired particle size and composition. A variety of membrane fabrication techniques, such as screen printing, dry pressing, and manual blade coating were employed to construct the bi-layer electrolyte membranes, aiming for uniformity and high-density. Through extensive experimentation, the optimal sintering temperature for the bi-layer membrane was determined, which successfully produced a dense electrolyte layer with a thickness of 20-30μm. Furthermore, the maximal diffusion coefficient (Do) and activation energy for diffusion (Ea) values for barium ion diffusion within the BZCY172 material were determined using Fick’s second law model based on experimental data, offering new insights into material performance under high-temperature conditions. This thesis also tackled key challenges in proton-conducting SOC fabrication, such as optimizing the sintering process to enhance densification, controlling barium evaporation during high-temperature sintering, and incorporating suitable additives to promote grain growth and reduce porosity. Characterization techniques, including X-ray diffraction (XRD) and scanning electron microscopy (SEM), were employed to analyze the microstructure and chemical composition of the synthesized materials and fabricated membranes, further advancing the understanding of their performance in electrochemical applications. Overall, this research contributed to the field of hydrogen energy and proton-conducting SOCs by providing a detailed investigation into the fabrication and optimization of BZCY-based electrochemical systems.