Lithium-Oxygen Battery

Since the 1970s, engineers have been working on improving lithium-ion batteries using a concept known as a lithium-air battery. Although it’s been theorized that such a battery could quadruple the energy density of current lithium technology, in practice they have been plagued with problems including contamination from water vapor and carbon dioxide. Even prototypes running on pure oxygen proved to be inefficient because the process requires large amounts of energy (up to 30 percent of the electricity input) to change the oxygen from a gas to a solid and back again.

However, a new design was recently tested that uses oxygen which is hermetically sealed inside the battery itself in a chemical form known as lithium superoxide (LiO2). The superoxide is embedded in a matrix made of cobalt oxide that is bathed in a liquid electrolyte. The superoxide, which is highly unstable, surrenders some of its oxygen molecules to form either lithium peroxide (Li2O2) or lithium oxide (Li2O). These chemical reactions are what drive electrons to create current, which can be used to power a variety of devices from cell phones to electric vehicles. When connected to a power supply, the process simply works in reverse to recharge the system.

The fact that the oxygen is always in a solid state throughout the discharge/charge process is an important aspect of the design. Instead of using 30 percent of the input power to recharge, the new battery uses only 8 percent. And battery life is also prolonged, as tests have shown that only about 2 percent of its capacity is lost even after as many as 130 charge/ discharge cycles. The developers hope to take the design from prototype to product within a year.