Rechargeable lithium–air batteries: characteristics and prospects

High specific energy density batteries are attracting growing attention as possible power sources for electric vehicles (EVs). Lithium–air batteries are the most promising system, because of their far higher theoretical specific energy density than conventional batteries. However, no technical basis exists to support the high energy density estimated from calculation. In this review, we will discuss the state-of-the art of lithium–air (or oxygen) batteries, as well as prospects for the future, with a focus on materials.