A team of researchers at Northwestern University has created a new fuel cell with a perovskite-based cathode, that offers both exceptional power densities and long-term stability at optimal temperatures.
"For years, industry has told us that the holy grail is getting fuel cells to work at 500-degrees Celsius and with high power density, which means a longer life and less expensive components," said the team. "With this research, we can now envision a path to making cost-effective fuel cells and transforming the energy landscape."
Though recent research had demonstrated the potential of some protonic ceramic fuel cells to offer environmentally sustainable and cost-effective electric power generation, those cells' high electrolyte conductivities failed to produce anticipated power outputs. "While it was known that some electrolytes have high conductivity at 500-degrees Celsius, somehow the electrodes were not working well in the complete fuel cell," the researchers said.
The team overcame this challenge by combining a high-activity cathode - the double-perovskite cathode PBSCF - with a new composition of matter, a chemically stable electrolyte labeled BZCYYb4411, to produce exceptional power density and stability in the highly prized intermediate temperature regime. This novel electrolyte allowed ions to move quickly and, unlike many previous electrolytes, remained stable even when operated for many hundreds of hours.
"We solved multiple problems simultaneously by changing out the electrode, improving the electrolyte and creating good contact and communication between the two materials," said the team.
The next challenge is to develop scalable manufacturing routes. Currently, getting the excellent contact between electrode and electrolyte requires a costly processing step. To bolster commercialization efforts, the team has ideas on how to approach this in a more cost-effective manner. They will also investigate making the fuel cells reversible, which would transfer electricity back into hydrogen for placement on grid backup.