Graphene/antimonene/graphene heterostructure: A potential anode for sodium-ion batteries

Antimony has been regarded as a promising anode for Na-ion batteries (NIBs) owing to its high specific capacity and electrical conductivity, as well as low potential range. However, its practical application is largely hindered by the poor cyclability due to the acute pulverization. Herein, we propose a trilayer graphene/antimonene/graphene (G/Sb/G) heterostructure as a potential anode material for NIBs. The aim of this anode design is to markedly increase the surface active sites via modifying the two-dimensional morphology and to alleviate volume expansion by introducing the graphene buffer. Based on density functional theory calculations and ab initio molecular dynamics simulations, the structural, electronic, mechanical properties, and the Na storage characteristics of the G/Sb/G heterostructure are systematically investigated. The results indicate that the G/Sb/G heterostructure exhibits superior thermodynamic stability, good electronic conductivity and ultrahigh stiffness. The trilayer G/Sb/G heterostructure can provide strong binding with sodium and low-migration barrier for sodium, endowing the anode with high specific capacity and good rate capability. More importantly, the coupling interaction between graphene and antimonene can greatly suppress the structural destruction of the antimonene layer during the sodiation process, offering excellent cyclability. Our findings suggest that the G/Sb/G heterostructure is a promising anode material for practical NIBs.