A Critical Review on Superoxide‐Based Sodium–Oxygen Batteries

Abstract

Sodium superoxide (NaO2) based sodium–oxygen batteries (Na‐O2) possess high theoretical energy density and high energy efficiency that can be an alternative energy storage device to lithium‐ion batteries. However, the state‐of‐the‐art sodium–oxygen batteries are still far from real application due to the limited understanding of the cell chemistry and reaction mechanism. This article reviews the recent advances on NaO2‐based Na‐O2 batteries, especially focusing on the reaction mechanism and the stability of NaO2. The parasitic reactions from the highly active NaO2 are discussed. It is hoped this provides insightful understanding on the mechanism and the role of the discharge product in Na‐O2 batteries.

Critical advances in re-engineering the cathode-electrolyte interface in alkali metal-oxygen batteries

“…A sandwich structure of alkali metal (Li, Na or K)-electrolyte-cathode is widely used in traditional AMOBs [3][4][5][6][7] . Unlike other battery systems, the cathode of AMOBs can be viewed as either an open or semiopen structure because of the constant consumption and release of oxygen [8] .…”

Research Progress and Future Perspectives on Rechargeable Na‐O2 and Na‐CO2 Batteries

“…Following the subsequent charge process, the NaO 2 decomposes and releases oxygen; Na + is reduced to Na and plates on the sodium anode side at the same time. [ 32,33 ] Based on the discharge product NaO 2 , the theoretical energy density of Na‐O 2 batteries is calculated to be 1108 Wh kg −1 . [ 34 ] In addition, owing to the reversible electrochemistry of the oxygen/superoxide () redox pair, Na‐O 2 batteries could exhibit much lower charging overpotential compared to Li‐O 2 batteries with semi‐irreversible oxygen/peroxide() pairs.…”

Atomic/nano-scale in-situ probing the shuttling effect of redox mediator in Na–O2 batteries

“…Rechargeable sodium-oxygen (Na-O 2 ) batteries are considered a promising candidate for energy storage devices benefiting from their high theroretical capacity (1100 Wh kg À1 ), low cost, small charging overpotential, and improved coulombic efficiency compared with lithium-oxygen batteries (Li-O 2 ) [1][2][3][4]. However, Na-O 2 batteries are even further from comercialization comapred with Li-O 2 because of several critical chanllenges: limited rate performance, undesirable side reactions and poor cyclibility [5].…”

“…However, Na-O 2 batteries are even further from comercialization comapred with Li-O 2 because of several critical chanllenges: limited rate performance, undesirable side reactions and poor cyclibility [5]. Among many efforts made to improve the performances of metal-O 2 batteries, one promising strategy is employing homogeneous catalysts which are also known as redox mediators [1,6,7]. Unlike lithiumoxygen batteries, Na-O 2 batteries are exempted from high charge overpotentials.…”