PNNL

Abstract

Due to its high energy efficiency, sodium-oxygen (Na-O2) batteries have been extensively studied recently. One of the critical challenges for the development of the Na-O2 battery is the elucidation of the reaction mechanism, the reaction products, and thestructural and chemical evolution of reaction product as well as their correlation with the battery performance. Herein, in-situ TEM was employed to probe the reaction mechanism and the structural evolution of the discharge products in Na-O2 batteries. The discharge product is featured by the formation of both cubic and conformal NaO2. It has been noticed that the impingement of reaction product (NaO2) can lead to the coarsening of the particle through coalescence. We also investigated the stability of the discharge product, noticing that the reaction product NaO2 is stable in the case of solid electrolyte. The present work provide unprecedented insight for the development of the Na-O2 batteries.