Cooperative Effect of Redox Mediator and Ion Selective Membrane to Inhibit the Shuttle Effect for Li-O2 Battery with Large Cyclic Capacity

Aprotic lithium-oxygen (Li-O-2) batteries hardly cycle at the condition of high area capacity for realizing their high energy density, because the unconducive lithium peroxide (Li2O2) discharge product limits the electron transfer between electrode and O-2/Li2O2. Here, it is demonstrated that one of redox mediator (RM), triethylene glycol bis-2,2,6,6-tetramethylpiperidin-1-oxyl radical (D-TEMPO), can be effectively used to promote the electron transfer between electrode and Li2O2, which the shuttle effect of RM can be cooperatively inhibited by regulating the size of RM and the thickness of ion-selective membrane. As a result, the Li-O-2 battery coupled with double cathodes, D-TEMPO, and ion-selective membrane can be stably operated for 46 days at a capacity of 5 mAh cm(-2). The concept in this work provides the cooperative design of a stable solution-mediated pathway for high-capacity Li-O-2 battery with long cycle stability.

Automated summary

This study demonstrates a method to improve the cycling performance of lithium-oxygen batteries under high capacity conditions by using a redox mediator, D-TEMPO, which promotes the electron transfer between the electrode and Li2O2.