Atomic layer deposited TiO₂ on cathode gas diffusion layer for low humidity operation in hydrogen fuel cells

 

Myounghoon Choun^a, Sangho Chung^a, Hongrae Jeon^a, Sunghyun Uhm^b,c,*, Jaeyoung Lee^a,b,**

 

^a Electrochemical Reaction and Technology Laboratory, School of Environmental Science and Technology, Gwangju 500-712, South Korea

^b Ertl Center for Electrochemistry and Catalysis, RISE, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea

^c Advanced Materials and Processing Center, Institute for Advanced Engineering, Yongin-si, Kyounggi-do 449-863, South Korea

 

Summary

 

Polymer electrolytic hydrogen fuel cell require humidification to give power as output. Keeping suitable amount of humidity in the cell is not feasible. In this study, atom layer of TiO₂ was deposited in 100, 200, and 300 cycles. Contact angles of commercial gas diffusion layer and atomic layer deposited gas diffusion layer were analyzed. The coating of TiO₂ was analyzed using scanning electron microscope, transmission electron microscope, and X-ray photoelectron spectroscopy. The layer was deposited on Pt/C electrode to be used in fuel cell.

 

Results of different cycles of coating of TiO₂ were analyzed after every 100, 200, and 300 cycles. It was found that after 300 cycles of coating, TiO₂ coating covered the surface for used as terminals. It was found that there was a distinct improvement in the cell performance even at low humidity conditions with TiO₂ coated gas deposition layer. The best performance of the cell was obtained with TiO₂ thickness ranging from 20 nm to 40 nm. The enhanced performance arose because of hydrophilic nature of TiO₂ layer as it reduces the chances of back diffusion. With the development of hydrophilic TiO₂ coated gas deposited layer, the cell gives good performance even at low humidity. It removed the humidification system from old polymer electrolytic hydrogen fuel cells and also contributed to the commercialization of polymer electrolytic hydrogen fuel cells.

 

The variation of voltage with current density at fully humidification operation and without humidification and variation of cell voltage as a function of time under drying conditions and long term use have been shown in the following figure.

 

 

Aamir Alaud Din

aamiralauddin@gist.ac.kr