Collaborative Research & GOALI: Direct-Fed Ethanol Metal-Supported Solid Oxide Fuel Cells

When integrated with batteries, fuel cells can be used to significantly increase the range of electric vehicles, potentially even making long-haul electric aircraft possible. Most fuel cell technologies, however, rely on hydrogen as the fuel and so the low energy density of compressed hydrogen gas and the large energy input needed to produce cryogenic liquid hydrogen limit every-day transportation applications of this hybrid electrical energy technology.

Ethanol, a liquid under ambient conditions, constitutes a renewable and high energy density alternative to hydrogen, albeit with the drawback that the ethanol must be reformed to hydrogen in a complex chemical process before it can be fed to the fuel cell. In this proposal, the ethanol reforming process will be integrated with the fuel cell by developing a catalyst that accomplishes this chemical transformation on one of the fuel cell electrodes, eliminating the costly, heavy, and energy intensive reforming process.

The academic researchers developing this direct-feed ethanol fuel cell will partner with Nissan to advance their e-Bio Fuel-Cell automotive technology. If successful, the outcomes of this project include a total weight/cost reduction of the reformer/fuel cell system and a simplified fuel cell internal design. The proposed research builds on an existing collaboration between Nissan and the academic research team.

This GOALI proposal will support this close link between the industrial and academic research teams through a student internship program, introducing graduate students to interdisciplinary research involving material synthesis, catalyst engineering, and fuel cell technology at Nissan, Washington State University (WSU), and Stony Brook University (SBU). The proposed work will have broad impact on (1) research experiences for underrepresented undergraduate students through the Office of Multicultural Student Services at WSU and the Inclusive Education program at SBU; (2) promoting public awareness of the importance of science and engineering by collaborating with the Palouse Discovery Science Center at WSU and the Institute for STEM Education at SBU; and (3) attracting high school students to the fields of science and engineering by mentoring a high school team for regional science events and participating in the ACS Project SEED Program.

The results of the proposed research will be disseminated widely through the normal channels of publication and presentation at technical meetings.

In pursuit of practical direct-feed ethanol fuel cells that will enable long-distance electric transportation, the primary aims of this research program are to (1) develop ethanol reforming catalysts in the form of Mo-doped Ni (Ni-Mo) nanoparticles highly dispersed within a three-dimensionally ordered mesoporous BaO-based support that can strongly adsorb and activate H2O as the internal ethanol reforming layer over the conventional Ni-based fuel call anode, and (2) investigate the catalyst performance under conditions expected for transportation applications of direct-feed ethanol metal-supported solid oxide fuel cells (MS-SOFCs). A significant advantage of a direct-feed ethanol MS-SOFC is the simplicity afforded by not having to externally reform the ethanol fuel to hydrogen; however, under the harsh operating conditions of conventional MS-SOFC operation, the Ni-based anodes would quickly deactivate due to severe coking.

To address this issue, the academic research team will design the multifunctional bilayer anode by electro-spraying Ni-Mo nanoparticles as the internal reforming layer over the anode surface. To successfully fabricate this bilayer anode, the PIs will first tune the electronic structure of Ni-Mo nanoparticle by controlling the Mo doping level and then infiltrate the nanoparticles into the high surface area, three-dimensionally ordered mesoporous BaZr0.4Ce0.4Y0.2O3 (BZCY) support.

Operando X-ray absorption spectroscopy (XAS) and environmental transmission electron microscopy (E-TEM) will be used to determine the oxidation state and structure of the Ni-Mo/BZCY catalysts under the nominal ethanol-reforming reaction conditions to relate those measurements to observed catalytic performance. The PIs will also use in-situ Raman and DRIFT spectroscopy to investigate the relationship between catalyst molecular structure and reforming reaction mechanisms.

Based on the identified structure-activity relationships, the PIs will fabricate the high-performance Ni-Mo/BZCY internal reforming layer over the MS-SOFC anode and will use an in-situ Raman spectroelectrochemical system to investigate its internal reforming and overall electrochemical activity under actual SOFC operating conditions. Through the proposed Nissan internship program, graduate students will work with Nissan engineers to evaluate and validate model MS-SOFCs with the internal reforming layer at Nissan under test conditions relevant to the vehicle operation.

From these road profile tests, the power quality capability and performance of the direct-feed ethanol MS-SOFCs under a range of driving conditions will be assessed.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.