2D sandwich-like nanosheets of ultrafine Sb nanoparticles anchored to graphene for high-efficiency sodium storage

Abstract

Sb is considered a promising anode material for high-performance sodium-ion batteries (NIBs) owing to its high theoretical specific capacity (660 mAh·g−1). However, Sb shows a very large volume change (∼200%) during sodiation and desodiation, leading to poor electrochemical performance. Here, we designed and tested a sandwich-like graphene-supported Sb nanocomposite (denoted Sb@RGO@Sb), in which ultrafine Sb nanoparticles are uniformly anchored on a reduced graphene oxide (RGO) surface. The ultrafine Sb nanocrystals anchored on the RGO surface minimize the aggregation of Sb and inhibit restacking of the RGO sheets, leading to a minimum transport length for both ions and electrons. The graphene layer not only accommodates the large volume variation of Sb during cycling but also promotes the electron conductivity of the whole electrode. Owing to its unique structure, this sandwich-like composite exhibits superior sodium storage properties.