Polarization Analysis of Durable Low Loading Pt/C Electrodes Produced By Reactive Spray Deposition Technology for Low Humidity Conditions
Authors: Ouimet Ryan J. , Yu Haoran , Bonville Leonard J. , Maric Radenka 
Published: February 2020

In 2016, the transportation sector accounted for 28% of greenhouse gas emissions in the United States, according to the United States Environmental Protection Agency [1]. One way in which the transportation industry is looking to reduce the greenhouse gas emissions is in the production of fuel cell vehicles. Compared to vehicles with traditional internal combustion engines which emit greenhouse gases, fuel cell vehicles only emit water vapor. Through research and development of fuel cell and electrolyzer technologies, fuel cell vehicles have the potential to significantly reduce the greenhouse gas emissions related to the transportation sector.

In order to improve the viability of fuel cell vehicles, research must be done to reduce the cost of the fuel cell production, optimize the fuel cell to operate at low humidity conditions, and improve the durability of the catalyst. The primary method that will be used in this work to reduce the cost of fuel cell production is Reactive Spray Deposition Technology (RSDT). RSDT is a one-step flame-based process which can directly spray a Pt/C electrode onto a membrane using without additional drying steps. Previous work by Yu et al examined the use of RSDT to create low Pt loading electrodes for fuel cell applications [2]. With the cost-effect RSDT method chosen for the development of the fuel cells, the RSDT-produced catalyst coated membranes (CCMs) will be tested in 100% relative humidity conditions as a baseline as well as reduced humidity conditions used in fuel cell vehicle applications. To improve the fuel cell performance at lower humidity, we will look to make changes to the membrane and ionomer which can allow for improved conductivity at the desired operating conditions. Additionally, we will look to improve on the catalyst durability by adjusting the carbon support used in the Pt/C electrodes. Rather than using Ketjen black supports, a change to a more graphitized carbon will be used which will look to improve the stability and durability to improve the lifespan of the fuel cells used in this application.

The work presented will use the RSDT process to make the change in ionomer and carbon support to improve the performance of the fuel cell at low humidity conditions as well as improving the catalyst durability. We will also utilize the six-step analysis technique used by Yu et al to examine how these changes affect the contributions from the different polarization sources [2, 3]. By analyzing the polarization sources, we can determine how the changes to the ionomer and membrane as well as the carbon support all affect the polarization sources which will allow to better optimize the fuel cells moving and improve the future viability of fuel cell vehicles.

References

[1] U.S. EPA. “Sources of Greenhouse Gas Emissions” www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions

[2] H. Yu, L. Bonville, R. Maric. Journal of the Electrochemical Society, 165, 5 (2018).

[3] H. Yu, L. Bonville, R. Maric. Journal of the Electrochemical Society, 165, 15 (2018).