Atomic layer deposited TiO2 on cathode gas diffusion layer for low humidity operation in hydrogen fuel cells
Myounghoon Chouna, Sangho Chunga, Hongrae Jeona, Sunghyun Uhmb,c,*, Jaeyoung Leea,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
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