P6C5 monolayer as promising anode for high-performance sodium-ion batteries: Insights from DFT and AIMD study

Abstract

Recently, a lateral heterostructure (LHS) combining black phosphorene and graphene edges was developed, addressing volume change issues and enhancing capacity retention. However, unresolved geometric concerns require further investigation, particularly regarding its suitability as a sodium-ion battery (SIB) anode. We present three LHSs models, labeled (LHS PC)₁, (LHS PC)₂, and P₅C₆, all featuring edge contact symmetry (armchair direction) but with different interface defects. Through first-principles calculations, we compare their structural stability, electronic properties, and charge transfer mechanisms. P₅C₆ exhibits superior energetic stability and dynamic stability, with type II band alignment and a 0.73 eV direct band gap, indicating optimal charge diffusion. Electrochemical assessments reveal a low sodium migration barrier (0.019 eV), facilitating rapid charge-discharge rates, with a storage capacity of 590.5 mAh/g and intercalation at a low average voltage (0.27 V). Additionally, ab initio molecular dynamics (AIMD) confirm its thermal stability during sodium storage, underscoring P₅C₆'s potential as a promising SIB anode material.