Oxygen Vacancies in Lithium- and Sodium-Oxygen Batteries

Oxygen Vacancies in Lithium- and Sodium-Oxygen Batteries

Author: ChemSusChem

The rising use of renewable energy also increases the need for environmentally friendly and high-capacity energy storage devices. Lithium-oxygen batteries (LOBs) and analogous systems such as sodium-oxygen batteries (SOBs) could be useful in this context. However, the underlying chemistry and the electrochemical performance of such cells remain poorly understood. Catalysts can improve the performance of these types of batteries—for example, two-dimensional metal oxides such as 2D-Nb2O5.

Jia-Hui Li and Yang-Xin Yu, Tsinghua University, Beijing, China, have used density functional theory (DFT) calculations to investigate the role of oxygen vacancies on 2D-Nb2O5 in lithium- and sodium-oxygen batteries. Pristine Nb2O5 can promote the oxygen reduction reaction (ORR) of Li to form Li2O2 and further produce Li4O2, but cannot facilitate the ORR of sodium in sodium-oxygen batteries.

By introducing oxygen vacancies, the catalytic performance of Nb2O5 is modified. The oxygen-deficient Nb2O5 can facilitate the formation of the corresponding peroxides for both Li and Na. This is related to changes of Li- and Na diffusion energies. According to the team, oxygen-deficient Nb2O5 is suitable for use in SOBs. This work elucidates the influence of oxygen vacancies on the reaction in lithium- and sodium-oxygen batteries and highlights how the catalytic properties of materials can be modified by oxygen defects.



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