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

Abstract

Lithium−oxygen (Li−O 2 ) and lithium−carbon dioxide (Li−CO 2 ) batteries are emerging as promising energy storage devices. Bifunctional catalysts play a crucial role in the reduction and evolution reactions for rechargeable Li−O 2 and Li−CO 2 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−O 2 and Li−CO 2 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 (Li 2 O 2 and Li 2 CO 3 ). As a result, the Li−O 2 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−CO 2 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 ).

A Li–O2/CO2 battery based on bio-inspired engineering of the Bi2S3/PVP cathode

“…A Li–CO 2 battery, as an emerging technology, takes greenhouse gas CO 2 as the cathode and theoretically has a high specific energy density of 1876 W h kg −1 , which has the potential to provide a high specific energy density power source while effectively utilizing greenhouse gas CO 2 , providing hope for solving the current energy crisis and climate warming. 16–20 However, the charging process of rechargeable Li–CO 2 batteries involves the electrochemical oxidative decomposition of Li 2 CO 3 or the reversible reaction between Li 2 CO 3 and carbon species to generate CO 2 gas molecules and Li + ions, which largely depends on the choice of different catalysts. On the one hand, nonpolar CO 2 molecules of carbon–oxygen double bond rupture makes the dynamics of the electrochemical reduction of CO 2 a slow process.…”