Li–air batteries are potentially viable ultrahigh energy density chemical power sources, which could potentially offer specific energies up to ∼3000Whkg−1 being rechargeable. The modern state of art and the challenges in the field of Li–air batteries are considered. Although their implementation holds the greatest promise in a number of applications ranging from portable electronics to electric vehicles, there are also impressive challenges in development of cathode materials and electrolyte systems of these batteries.