Magnéli-Phase Ti4O7 Nanosphere Electrocatalyst Support for Carbon-Free Oxygen Electrodes in Lithium–Oxygen Batteries

Lithium–oxygen batteries have been considerably researched due to their potential for high energy density compared to some rechargeable batteries. However, it is known that the stability of a carbon-based oxygen electrode is insufficient owing to the promotion of carbonate formation, which results in capacity fading and large overpotential in lithium–oxygen batteries. To improve the chemical stability in organic-based electrolytes, alternative electrocatalyst support materials are required. The Ti–O crystal system appears to provide a good compromise between electrochemical performance and cost and is thus an interesting material for further investigation. Here, we investigate a carbon-free electrode with the goal of identifying routes for its successful optimization. To replace carbon materials as an electrocatalyst support, Magneli Ti4O7 nanospheres were synthesized from anatase TiO2 nanospheres via a controlled thermochemical reduction. The Magneli Ti4O7 nanospheres demonstrated effective overpotential...