Cation Additive Enabled Rechargeable LiOH‐Based Lithium–Oxygen Batteries

Lithium–oxygen (Li–O 2 ) batteries have attracted extensive research interest due to their high energy density. Other than Li 2 O 2 (a typical discharge product in Li–O 2 batteries), LiOH has proved to be electrochemically active as an alternative product. Here we report a simple strategy to achieve a reversible LiOH‐based Li–O 2 battery by using a cation additive, sodium ions, to the lithium electrolyte. Without redox mediators in the cell, LiOH is detected as the sole discharge product and it charges at a low charge potential of 3.4 V. A solution‐based reaction route is proposed, showing that the competing solvation environment of the catalyst and Li + leads to LiOH precipitation at the cathode. It is critical to tune the cell chemistry of Li–O 2 batteries by designing a simple system to promote LiOH formation/decomposition.