Co Single Atom-FeCo Alloy-Carbon Nanotube Catalysts on Graphene for Lithium-Oxygen and Lithium-Carbon Dioxide Batteries

Lithium-oxygen(Li-O-2) and lithium-carbondioxide (Li-CO2) batteries are emerging as promisingenergy storage devices. Bifunctional catalysts play a crucial rolein the reduction and evolution reactions for rechargeable Li-O-2 and Li-CO2 batteries. In this study, wesynthesized Co single-atom catalysts (SAC-(Co)) and FeCo alloy nanoclustersembedded on nitrogen-doped carbon nanotubes (NCNTs) grown on a reducedgraphene oxide (rGO) catalyst (SAC-(Co)-FeCo-NCNT/rGO) for use in Li-O-2 and Li-CO2 applications. We found thatthe SAC-(Co), FeCo, and NCNTs offer excellent electrocatalytic performancedue to their synergistic effect, while the open-space structure ofthe NCNTs and rGO provides a large void for the storage of dischargeproducts (Li2O2 and Li2CO3). As a result, the Li-O-2 battery with the novelbifunctional catalyst showed a deep discharge capacity of 29498 mAhg(-1) (at 200 mA g(-1)) and a goodcycle ability (>100 cycles at 500 mAh g(-1) and200mA g(-1)), while the Li-CO2 batteryexhibited a deep discharge capacity of 43463 mAh g(-1) (at 200 mA g(-1)) and good cycle ability (>200cyclesat 500 mAh g(-1) and 500 mA g(-1)). SAC-(Co)-FeCo-NCNT/rGO catalyst for applicationsof Li-O-2 and Li-CO2 batteries