Ion transport and mechanical properties of N-doped graphene composite Li3N SEI: A first principles calculation

Abstract

An artificial solid electrolyte interface (SEI) provides an effective way to solve the instability of the metal lithium anode interface, avoid the growth of lithium dendrites and alleviate the interface fluctuations caused by volume expansion. A first principles method was used to calculate the stability of the double-layer SEI of nitrogen-doped graphene composites with lithium nitride (NGs/Li3N), including low-concentration doped graphene (NG-1, NG-2 and NG-3) with nitrogen atoms (1–3), graphene nitride (C2N) and graphite phase carbon nitride (g-C3N4) in the doped state. The adsorption and migration of lithium ions on the surface and interface of the heterostructure and the ability of the critical tensile strain to regulate the diffusion of lithium at the interface of the heterostructure were calculated. The optimal diffusion path of the NG-2/Li3N heterostructure graphene terminal and the interface is the same. The difference (0.114 eV) in the diffusion energy is the smallest. Under mechanical strength, the NG-2/Li3N heterostructure limits the interface deformation caused by the adsorption of lithium and increases the stability of the adsorption of lithium at the interface. A nitrogen-doped graphene composite lithium nitride layered SEI exhibiting a synergistic interface effect was constructed to regulate the deposition of lithium and inhibit the growth of dendrites.