by Kimberly Geiger, Michigan Technological University
(A) Schematic of the CSSFC, porous SOFC, and conventional SOFC. (B) The I-V-P performance of various fuel cell setups running on CH4 at 550°C using anodes made of Ni-BZCYYb. (C) The oxygen ionic conductivities of various electrolytes, with or without carbonate modification, plotted according to temperature using the Arrhenius method. (D) DSC charts of several electrolytes in an environment of argon. Acknowledgment: National Academy of Sciences Proceedings (2022). The doi: 10.1073/pnas.2208750119
Fuel cells use an electrochemical process to produce energy, just like batteries do. They don’t run out of juice or need to be recharged, unlike batteries. However, issues with cost, performance, and durability outweigh any possible benefits of fuel cells.
Yun Hang Hu, a researcher at Michigan Technological University, and two graduate students, Hanrui Su and Wei Zhang, took on those problems and altered the fuel cell’s typical trajectory by forming an ultrafast oxygen ion transfer channel by forming an interface between the electrolyte and molten carbonate.
Hu, who teaches materials science and engineering at Michigan Tech and holds the Charles and Carroll McArthur Endow Chair Professorship in Materials Science and Engineering, said, “This allowed us to invent an entirely new type of fuel cell, a carbonate-superstructured solid fuel cell (CSSFC).”
Like other fuel cells, CSSFCs offer a broad range of possible applications, ranging from powering whole power plants to fuel cell cars and household power generation. Compared to alternative fuel cell types, CSSFCs have higher durability and energy conversion efficiency at lower operating temperatures because of their fuel flexibility.
The majority of fuel cells run on hydrogen, which is usually created through the costly process of reforming hydrogen-containing molecules, most frequently methane. However, Hu’s lab invented the CSSFC, which can directly use hydrocarbon fuels like methane.
Hu stated that commercial applications are especially interested in fuel flexibility. Additionally, there are a number of benefits to the new fuel cell’s electrochemical performance at lower operating temperatures. “The operating temperature of a conventional solid oxide fuel cell is usually 800 degrees Celsius or higher, because ion transfer in a solid electrolyte is very slow at a lower temperature,” Hu explained. “In contrast, the CSSFC’s superstructured electrolyte can provide a fast ion transfer at 550 degrees Celsius or lower—even as low as 470 degrees Celsius.”
High theoretical efficiency and reduced cell construction costs are provided by the comparatively low operating temperature. According to Hu, it might also be safer to use than other kinds of solid fuel cells.
A record-breaking high open circuit voltage (OCV), which denotes negligible current leakage loss and excellent energy conversion efficiency, was also seen during CSSFC tests.
Hu believes that the fuel efficiency of CSSFC may attain 60%. In contrast, a combustion engine’s typical fuel efficiency falls between 35% and 30%. Because of the CSSFC’s improved fuel efficiency, cars may emit less carbon dioxide.
The study has been published in the National Academy of Sciences Proceedings.