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, Magnéli Ti4O7 nanospheres were synthesized from anatase TiO2 nanospheres via a controlled thermochemical reduction. The Magnéli Ti4O7 nanospheres demonstrated effective overpotential characteristics (1.53 V) compared to the anatase TiO2 nanospheres (1.91 V) during charge-discharge cycling at a current rate of 100 mA g-1. Additionally, RuO2@Magnéli-Ti4O7 nanospheres were prepared as a bifunctional catalyst-containing oxygen electrode for lithium-oxygen batteries, providing a remarkably reduced overpotential (0.9 V).
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Ministry of Science, ICT, and Future Planning [NRF-2016R1A2B2012728, NRF-2016M3A7B4909318] and by the institutional research program of the Korea Institute of Science and Technology [2E26081-16-054]. This work was also supported by a Korea University Grant.
© 2018 American Chemical Society.
- Li-O batteries
- Magnéli phase
ASJC Scopus subject areas