In this work, we perform a first-principles study of graphene, nitrogen-, boron-doped graphene, and codoped graphene as the potential catalysts in nonaqueous lithium-oxygen (Li-O2) batteries. Among the samples studied, boron-doped graphene exhibits the lowest discharge and charge overpotentials, suggesting that boron-doped graphene is the best catalyst for both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) in nonaqueous Li-O2batteries. Another significant finding is that codoping of nitrogen and boron atoms does not enhance the ORR/OER in the presence of lithium atoms, indicating that the synergistic effect in the presence of protons does not appear in nonaqueous Li-O2batteries. This behavior is attributed to the fact that the existence of lithium atoms can change the most stable adsorption sites and adsorption energies of intermediates. Finally, on the basis of our calculation results, we propose that the adsorption energy of intermediates in the rate-determining step (RDS) can be the descriptor of the overpotential, and the lower adsorption energy in RDS represents the lower overpotential. The findings reported in this work contribute to the understanding of the ORR/OER in nonaqueous Li-O2batteries and provide useful insight into the catalyst design. (Graph Presented).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films