Date of Award


Document Type

Campus Access Dissertation

Degree Name

Doctor of Philosophy in Environmental Engineering (PhD)

Administrative Home Department

Department of Materials Science and Engineering

Advisor 1

Yun Hang Hu

Committee Member 1

Kazuya Tajiri

Committee Member 2

Miguel Levy

Committee Member 3

John Jaszczak


Solid oxide fuel cells (SOFCs) have gained prominence as high-efficiency electric generators, yet their high operating temperatures (>800 oC) present challenges in terms of system cost, complexity, and long-term durability. Lowering the operating temperature to the low-temperature range (≤ 650 oC) has garnered significant attention, especially for utilizing hydrocarbons as fuels. However, the critical issue for low-temperature SOFCs is the polarization losses resulting from temperature reduction. This dissertation presents groundbreaking research on a novel fuel cell type known as the carbonate-superstructured solid fuel cell (CSSFC). A key innovation in CSSFCs lies in the in-situ generation of a eutectic carbonate phase (Li2CO3/Na2CO3) on the porous samarium-doped ceria (SDC). The interface between SDC and melted eutectic carbonates provides a fast transfer channel for oxygen ions and plugs the microchannels to prevent gas leakage, which enhances the oxygen ionic conductivity of solid electrolyte by 20-fold (from 3.5×10–3 to 7.3×10–2 S cm– 1), resulting in a six-fold increase in peak power density (PPD), reaching 215 mW cm–2 with dry methane fuel at 550 oC, surpassing all reported values of electrolyte-supported SOFCs. Furthermore, we integrated photo energy into the CSSFC system by introducing light illumination into the thermal catalytic CO2 reforming of ethane in the anode, creating a thermo-photo anode process for CSSFCs. Light-enhanced fuel activation leads to an outstanding cell performance, with a record peak power density of 168 mW cm−2 at 550 oC, with no observed degradation over ~50 hours of operation. Additionally, incorporating

finer-scale gradient anode functional layers further enhances internal reforming reactions, reduces electrode polarization resistance, and increases PPD to 241 mW cm–2 at 550 oC with ethane fuels. The CSSFCs with gradient anodes maintain excellent durability with ethane fuels for over 200 hours. In conclusion, CSSFCs offer a promising platform for efficient electrochemical energy conversion with fuel flexibility, simplified fabrication, and reduced costs. These innovative developments in CSSFC technology, integration of photo energy, and anode design contribute significantly to advancing the field of low-temperature SOFCs and offer new prospects for sustainable energy generation.

Available for download on Thursday, November 21, 2024