ABSTRACT
Regardless of the type of rechargeable metal-air batteries (RMABs), the air-electrodes (or cathodes) must be continuously suppliedby active materials (oxygen from air or pure oxygen). The core component of an air-electrode is the bifunctional catalyst. Besides the catalyst's contribution to improve the mass transport of reactants and products due to its porous structure, it can also speed up both the ORR and OER kinetics. Inevitably, the physicochemical properties of such a bifunctional catalyst exert a significant effect on the efficiency of air-electrodes. This chapter 6 summarizes and analyzes the battery performance and bifunctionality by validating various catalysts as air-electrodes in RMABs. It is demonstrated that to obtain high battery performance, a trade-off strategy should focus on the selection of optimal catalyst formulation and structure, as well as its integration into the remaining air-electrode components. Also, this chapter 6 emphasizes the current challenges of bifunctional catalysts and then points out the future research directions in developing bifunctional catalysts for RMABs.
