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

Lithium-oxygen (Li-O2) and lithium-carbon dioxide (Li-CO2) batteries are emerging devices for energy storage applications. The bifunctional catalysts play an important role in the reduction and evolution reactions for the rechargeable Li-O2 and Li-CO2 batteries. Here, we synthesize Co single-atom catalysts (SAC(Co)) and FeCo alloy nanoclusters embedded on the nitrogen-doped carbon nanotube (NCNT) grown on reduced graphene oxide (rGO) catalyst (SAC(Co)-FeCo-NCNT/rGO) for the Li-O2 and Li-CO2 applications. We find that the SAC(Co), FeCo, and NCNTs provide an excellent electrocatalytic performance due to the synergic effect while the open-space structure of the NCNTs and rGO offers a large void for the storage of the products (Li2O2 and Li2CO3) during the discharge process. As a result, the Li-O2 battery with the novel bifunctional catalyst shows a deep discharge capacity of 29498 mAh g-1 (at 200 mA g-1) and a good cycle ability (> 100 cycles at 500 mAh g-1 and 200 mA g-1), while Li-CO2 battery shows a deep discharge capacity of 43463 mAh g-1 (200 mA g-1) and good cycle ability (>200 cycles at 500 mAh g-1 and 500 mA g-1).