Lithium–Air Battery Mediator

Redox mediators (RMs) have been proposed as a promising solution to two challenging drawbacks of Li–air batteries: high overpotential during charge and electrode passivation during discharge. In the recent decade a wide range of RMs with different properties has been applied to both the discharge and charge reaction. Here we reviewed the studies on RMs with a focus on the electrochemical and physical properties, which are vital for their role as RMs, including redox potentials, stabilities, and diffusivities. We present the state-of-the-art landscape of the mediators' performance and the understanding in their reaction mechanism. Future directions in developing the effect of RMs are given based on our comprehensive perspectives.