Researchers have created molten air batteries using iron, carbon and vanadium boride because of their ability to transfer multiple electrons. These batteries can store three, four and 11 electrons per molecule respectively, giving them 20 to 50 times the storage capacity of a lithium battery, which can only store one electron per molecule of lithium.

Credit: William Atkins, the George Washington University

A molten air battery configuration: The air electrode (circle, left) and the metal electrode (right) are lowered into the crucible (white cup), then covered with electrolyte, which is then heated until it is molten. Molten air batteries have the highest intrinsic electric energy storage capacities of any other batteries to date.

Credit: William Atkins, the George Washington University