Chemists make breakthrough on road to creating a rechargeable lithium-oxygen battery. Chemists have successfully resolved two of the most challenging issues surrounding lithium-oxygen batteries, and in the process created a working battery with near 100 per cent coulombic efficiency. The new work demonstrates that four-electron conversion for lithium-oxygen electrochemistry is highly reversible. The team is the first to achieve four-electron conversion, which doubles the electron storage of lithium-oxygen, also known as lithium-air, batteries. Source 3e.