Oxygen-free cell formation process obtaining LiF protected electrodes for improved stability in lithium-oxygen batteries

The unsatisfactory stabilities of carbon-based cathodes and lithium anodes are the major hurdles limiting the development of Li-air (O2) batteries. Herein, we propose an extremely simple cell formation process for non-aqueous Li-O2 batteries, by a discharge-charge process in argon prior to O2 atmosphere, to produce protective films on both CNTs-cathode and lithium-anode surfaces. The films are mainly composed of lithium fluoride derived from LiTFSI decomposition and endows lithium oxygen batteries with enhanced cycling stability (>200 cycles) under a consistent capacity condition (1000 mAh g−1). This study reveals that LiF-rich films could effectually suppress the parasitic reactions of electrodes against the reactive intermediates and electrolyte attacks. This simple approach provides a new strategy to protect both electrodes for lithium oxygen batteries.