2D MoSi₂N₄ as electrode material of Li-air battery — A DFT study

Li-air batteries are one of the most promising next-generation batteries. The development of 2D layered materials enriches the materials for Li-air batteries. In this work, a DFT study of the configuration and energetics of Li atoms on 2D MoSi₂N₄ is presented. We propose 2D MoSi₂N₄ as a suitable material for both anode and cathode materials of Li-air batteries. The high Li ion conductivity of 2D MoSi₂N₄ brings advantages for it to be an anode, and the low barrier for Li₂O₂ growth on 2D MoSi₂N₄ brings advantages for it to be a cathode material. The maximum capacity of Li-loaded MoSi₂N₄ is predicted to be 129 mAh/g. For Li-loaded MoSi₂N₄, the anode potential is stable (~ -0.2 V relative to Li bulk) in a wide range of Li loading (Li% = 12 ~ 75%). As the cathode, the open-circuit cathode potential is stable (~ 2.8 V relative to Li bulk) during the growth of Li₂O₂ slab. Our work reveals the possibility of 2D MAX phases (M is transition metal, A is Al or Si, and X is C, N, or both) as metal-air battery materials.