Theoretical study of catalytic performance of X-γ-Graphyne as cathodes for lithium-air batteries

Lithium-air batteries (LiO2) are considered one of the most promising energy storage and conversion device candidates for future mobility applications, such as electric vehicles, due to their ultrahigh theoretical energy density (up to similar to 3600 Wh kg(-1)). The main goal in this work is to study an electrochemical catalytic model for a cathode in LiO2 batteries to simulate the OER during the discharging process. Density Functional Theory (DFT) calculations were performed to investigate gamma-Graphyne and N-gamma-Graphyne (N-Doped gamma-Graphyne) as the potential cathode catalyst for LiO2 batteries. gamma-Graphyne and N-gamma-Graphyne surfaces exhibit high stability according to calculations, the pristine surface exhibits a slight improvement in the formation energy of LixO2, moreover, the N-Doped surface can reduce the significant formation energy of LixO2 in the OER. Calculations explain the catalytic mechanism and identify the active sites to perform N-doping on pristine gamma-Graphyne. This study demonstrates a feasible approach to achieve designed gamma-Graphyne and N-gamma-Graphyne as cathode catalysts for Li air batteries, which is promising for cost reduction in mass production of Li-air batteries.