Suppression of Gas Crossover and Dendrite Growth in Sodium–Gas Batteries across a Wide Operating Temperature Range

Enabling highly stable alkali metal anodes in gas atmospheres, such as oxygen and carbon dioxide, is critical for the implementation of emerging metal–gas batteries with high energy density and improved safety. Herein, we demonstrate a three-salt electrolyte system to tackle the problems of gas crossover and uncontrolled metallic dendrite growth for all-climate sodium–gas batteries by the formation of an electrochemically/chemically stable solid electrolyte interphase that is rich in fluoride and sulfate compounds. Consequently, the sodium metal anodes present high reversible capacity (10 mAh cm–2 at 1.5 mA cm–2) and long cycle life (2000 h) in gas atmospheres across a wide operating temperature range. Using the three-salt electrolyte, all-climate sodium–oxygen and sodium–carbon dioxide batteries are demonstrated with a reversible capacity of 1000 mAh g–1 over 100 cycles at ambient temperature and good adaptability to temperatures from −60 to 60 °C.