(532ce) Probing Discharge Mechanisms in Aprotic Na-O2 Batteries and Their Implications on the Overall Cell Performance

Aprotic M-O₂ (where M = Li/Na) batteries have gained significant recent attention as viable alternatives to commercial Li-ion batteries owing to their high energy densities and reversible redox chemistries^1–3. Among these, Na-O₂ batteries have been considered promising⁴. However, Na-O₂ batteries are challenged by their long-term stability and lack of fundamental understanding of the mechanisms that govern their electrochemistry, which has hampered the development of effective strategies to improve their performance⁵. In this presentation, we discuss how variations at the cathode solid/aprotic solvent interfaces affect the mechanism of discharge product formation and the consequent implication of this in the overall performance and long-term stability of the Na-O₂ batteries. Combining electrochemical measurements, X-ray diffraction, scanning electron microscopy, and density functional theory, we probe the effects of key parameters of the interface, such as the cathode surface area and the nature of the aprotic solvent, on the nature of the discharge product formation and their resulting subsequent disproportionation under rest and charging conditions. These insights are critical toward devising ways to improve the stability of Na-O₂ batteries.

References:

1. Samira, S., Deshpande, S., Greeley, J. & Nikolla, E. Aprotic Alkali Metal–O2 Batteries: Role of Cathode Surface-Mediated Processes and Heterogeneous Electrocatalysis. ACS Energy Letters 6, 665–674 (2021).
2. Samira, S. et al. Nonprecious Metal Catalysts for Tuning Discharge Product Distribution at Solid–Solid Interfaces of Aprotic Li–O2 Batteries. Chemistry of Materials 31, 7300–7310 (2019).
3. Nacy, A., Ma, X. & Nikolla, E. Nanostructured Nickelate Oxides as Efficient and Stable Cathode Electrocatalysts for Li–O2 Batteries. Topics in Catalysis 58, 513–521 (2015).
4. Zhao, S., Qin, B., Chan, K. Y., Li, C. Y. V. & Li, F. Recent Development of Aprotic Na−O2 Batteries. Batteries and Supercaps vol. 2 725–742 (2019).
5. Bi, X., Wang, R., Amine, K. & Lu, J. A Critical Review on Superoxide‐Based Sodium–Oxygen Batteries. Small Methods 3, 1800247 (2019).