A new catalyst developed at Los Alamos National Laboratory promises to replace platinum and other precious metals usually required for fuel cells. The new material is constructed from carbon nanotubes created from graphene. By lowering the cost of fuel cells, this new material could help revolutionize the way green energy powers everything.
Los Alamos researchers Hoon T. Chung, Piotr Zelenay, and Jong H. Won developed the new catalyst. The material consists of carbon nanotubes and nanoparticles created from graphene, to which nitrogen is introduced. Chung and his team found a simple way to make the new material in one step, using iron acetate and cyanamide, a chemical commonly used in agriculture and the pharmaceutical industry.
To create the new catalyst, researchers mixed one part of iron acetate with three-and-a-half parts of cyanamide in a beaker and stirred it over heat for three hours. They then added carbon powder and stirred the mixture overnight. The mixture was then heated, cleaned, and heated again.
The new material reduces more oxygen than any other known catalyst not made from precious metals. This is critical for storing electricity, especially in renewable energy plants that see sporadic power production, such as from the Sun or wind. In many respects, this carbon-based catalyst performed as well in testing as far more expensive catalysts made from precious metals.
Lithium-air fuel cells created with the graphene-based catalyst have far more storage capacity than the best lithium-ion batteries. Cells made with the new catalyst could power cars, and make producing electricity through renewable means more economical.
"A lithium-air secondary battery, potentially the most-promising metal-air battery known, has an energy storage potential that is 10 times greater than a state-of-the-art lithium-ion battery," Zelenay said.
While in the process of creating the new material, researchers also discovered that cyanamide can be used to form carbon nanotubes. The nanotubes in the new catalyst are small - only about one-millionth of an inch in diameter and one-twenty-five-hundredth of an inch long.
"[T]he new catalyst makes possible the creation of economical lithium-air batteries that could power electric vehicles, or provide efficient, reliable energy storage for intermittent sources of green energy, such as windmills or solar panels," Zelenay said.
Announcement of the new material was made in the journal Nature Communications.