Highly efficient and stable solid-state Li–O2 batteries using a perovskite solid electrolyte

Abstract

The solid-state Li–O₂ battery is considered an ideal candidate for high-performance energy storage because of its high safety, due to use of non-flammable and non-volatile electrolytes, and high specific energy, as it uses Li metal and O₂ gas as active materials. We present an original solid-state Li–O₂ cell composed of a Li metal anode, a flexible polymer interlayer, a perovskite-structured Al-doped Li–La–Ti–O (A-LLTO) solid electrolyte, and an integrated cathode in which a porous A-LLTO solid electrolyte frame was covered with a carbon layer and CoO nanoparticles as the catalyst for the cyclic oxygen evolution and reduction reactions. The designed solid-state cell operated safely in pure O₂ atmosphere at temperatures from 25 °C to 100 °C and delivered the first discharge capacity from 796 mA h g_C+CoO⁻¹ to 4035 mA h g_C+CoO⁻¹, respectively, at a current density of 0.05 mA cm⁻². Notably, at 50 °C, the cell was maintained for 132 cycles under a limited capacity mode of 500 mA h g_C+CoO⁻¹ at a high current density of 0.3 mA cm⁻², demonstrating the first step of success towards realizing Li batteries with high energy and cyclability, as well as safety.