A self-encapsulated porous Sb-C nanocomposite anode with excellent Na-ion storage performance

In this study, a self-encapsulated Sb-C nanocomposite as an anode material for sodium-ion batteries (SIBs) was successfully synthesised using an SbCl₃-citrate complex precursor, followed by a drying and calcination process under an inert N₂ atmosphere. When the molar ratio of SbCl₃ to citric acid was varied from 1 : 1 to 1 : 4, the Sb-C nanocomposite with a molar ratio of 1 : 3 (Sb-C3) exhibited the highest specific surface area (265.97 m² g^-1) and pore volume (0.158 cm³ g^-1). Furthermore, the Sb-C3 electrode showed a high reversible capacity of 559 mA h g^-1 at a rate of C/10 and maintained a high reversible capacity of 430 mA h g^-1 even after 195 cycles at a rate of 1C. The Sb-C3 electrode exhibited an excellent rate capability of 603, 445, and 357 mA h g^-1 at the rates of C/20, 5C, and 10C, respectively. Furthermore, a full cell composed of an Sb-C3 anode and a Na₃V₂(PO₄)₃ cathode exhibited good specific capacity and cyclability, making the Sb-C composite a promising anode material for high-performance SIBs.