Recent Development of Aprotic Na−O2 Batteries

The development of batteries with high energy density and low costs involves chemistry beyond lithium‐ion batteries. Rechargeable sodium‐oxygen (Na−O2) batteries make two essential steps forward: i) replacing Li by Na to remove the bottleneck in resources supply and ii) using oxygen from air to raise the theoretical energy density. A lot of progress has been made in performance and understanding of Na−O2 battery since its first report in 2012. However, there remain significant challenges, such as the instability of discharge products, dendrite growth of Na metal, and the crossover of superoxide. A timely review is given here to summarize the challenges encountered in the components of the Na−O2 battery. Insights are offered on sodium anode protection, morphology dynamics at the cathode, amphibian presence of superoxide, and the roles of electrolyte. Bright prospects in further development of aprotic Na−O2 batteries are envisioned.