Highly flexible free-standing Sb/Sb2O3@N-doped carbon nanofiber membranes for sodium ion batteries with excellent stability

Sb and Sb2O3 are attractive anode materials for sodium ion batteries due to their relatively low cost and high theoretical capacity. However, the poor cycling stability caused by serious volume expansion hinders their development. In this work, we use electrospinning and carbon thermal reduction to easily synthesize Sb/Sb2O3@N-doped carbon nanofiber membranes. The flexible Sb/Sb2O3@NCNF membranes are directly used as free-standing electrodes in SIBs showing a high specific capacity and excellent cycling stability (527.3 mA h g−1 after 100 cycles at 0.1 A g−1). They can still deliver a reversible specific capacity around 400 mA h g−1 after 700 cycles even at 1 A g−1. The flexible free-standing design, simple synthesis methods and excellent electrochemical properties make the Sb/Sb2O3@NCNF electrodes an ideal anode candidate material for sodium ion batteries.