Recent advances in cathode catalyst architecture for lithium–oxygen batteries

Lithium–oxygen (Li–O2) batteries have great potential for applications in electric devices and vehicles due to their high theoretical energy density of 3500 ​Wh kg−1. Unfortunately, their practical use is seriously limited by the sluggish decomposition of insulating Li2O2, leading to high OER overpotentials and the decomposition of cathodes and electrolytes. Cathode electrocatalysts with high oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities are critical to alleviate high charge overpotentials and promote cycling stability in Li–O2 batteries. However, constructing catalysts for high OER performance and energy efficiency is always challenging. In this mini-review, we first outline the employment of advanced electrocatalysts such as carbon materials, noble and non-noble metals, and metal–organic frameworks to improve battery performance. We then detail the ORR and OER mechanisms of photo-assisted electrocatalysts and single-atom catalysts for superior Li–O2 battery performance. Finally, we offer perspectives on future development directions for cathode electrocatalysts that will boost the OER kinetics.