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

Abstract

Lithium–oxygen (Li–O2) and lithium–carbon dioxide (Li–CO2) batteries are emerging as promising energy storage devices. Bifunctional catalysts play a crucial role in the reduction and evolution reactions for rechargeable Li–O2 and Li–CO2 batteries. In this study, we synthesized Co single-atom catalysts (SAC(Co)) and FeCo alloy nanoclusters embedded on nitrogen-doped carbon nanotubes (NCNTs) grown on a reduced graphene oxide (rGO) catalyst (SAC(Co)-FeCo-NCNT/rGO) for use in Li–O2 and Li–CO2 applications. We found that the SAC(Co), FeCo, and NCNTs offer excellent electrocatalytic performance due to their synergistic effect, while the open-space structure of the NCNTs and rGO provides a large void for the storage of discharge products (Li2O2 and Li2CO3). As a result, the Li–O2 battery with the novel bifunctional catalyst showed 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 the Li–CO2 battery exhibited a deep discharge capacity of 43463 mAh g–1 (at 200 mA g–1) and good cycle ability (>200 cycles at 500 mAh g–1 and 500 mA g–1).