Modified Tetrathiafulvalene as an Organic Conductor for Improving Performances of Li-O₂ Batteries

Large over-potentials owing to the sluggish kinetics of battery reactions have always been the drawbacks of Li-O₂ batteries, which lead to short cycle life. Although redox mediators have been intensively investigated to overcome this issue, side-reactions are generally induced by the solvated nature of redox mediators. Herein, we report an alternative method to achieve more efficient utilization of tetrathiafulvalene (TTF) in Li-O₂ batteries. By coordinating TTF⁺ with LiCl during charging, an organic conductor TTF⁺ Cl_x^- precipitate covers Li₂ O₂ to provide an additional electron-transfer pathway on the surface, which can significantly reduce the charge over-potential, improve the energy efficiency of Li-O₂ batteries, and eliminate side-reactions between the lithium metal anode and TTF⁺ . When a porous graphene electrode is used, the Li-O₂ battery combined with TTF and LiCl shows an outstanding performance and prolonged cycle life.