Effect of singlet oxygen on redox mediators in lithium-oxygen batteries

The use of a redox mediator (RM) to chemically decompose Li 2 O 2 is an efficient approach to improve the efficiency and cyclability of lithium-oxygen batteries. It has been suggested that RMs can react with the singlet oxygen ( 1 O 2 ) but no attempt has been made to categorize the reactivity of different RMs with 1 O 2 , or investigate the impact of this reaction on the electrochemical behavior of RMs. Here we show that the reactivity of RMs with 1 O 2 depends on the unique chemistry of the RM, and that the Li 2 O 2 decomposition kinetics of RMs are considerably affected by their reactivity towards 1 O 2 . We examine changes to the chemical and electrochemical properties of RMs after exposure to 1 O 2 . These results suggest that the activity and lifetime of RMs in Li-O 2 cells are affected by their reactivity towards 1 O 2 , and that RMs can be classified depending on how easily they react with, or physically quench 1 O 2 . 1 O 2 reacts with RMs but the effect of 1 O 2 on the function of RMs has been ambiguous. In this work we show the effect of RMs functionality from various perspectives and classified them following the reaction of RMs with 1 O 2 .