Storing energy in batteries is an increasingly important aspect of the modern world. Electric cars and giant battery banks for electric utilities require high-capacity batteries. The majority of these batteries are lithium-ion batteries that come in a number of different varieties based on the other elements used to make them.
Lithium-ion batteries mostly incorporated cathodes containing cobalt and nickel until fairly recently. But these metals are expensive and bring with them other complications. Most of the world’s cobalt comes from the Democratic Republic of the Congo and most of the Congo’s output is controlled by China. The mines there reportedly employ children in hazardous working conditions and the mining is harmful to the environment.
More recently, iron has become a replacement for cobalt and nickel in many lithium-ion battery cathodes. Iron is much less expensive and doesn’t involve a host of other problems. However, iron-based batteries have some performance compromises primarily associated with their operating voltages and energy levels.
Researchers at Stanford University have discovered a way to produce a form of iron with a higher oxidation state that can permit the development of a high-voltage, reversible, and stable battery cathode. The process involves the fabrication of extremely small crystalline particles whose electrical properties are quite different from conventional forms of iron.
Now that the researchers have figured out how to create iron particles at a higher oxidation state and keep them there, they are working on solving practical engineering problems that need to be solved in order to lead to commercial applications of high-performance, lower-cost lithium-ion batteries.
