The Sb/SbPO4@3D-G composite as a promising anode material for sodium-ion batteries

In this work, an Sb/SbPO4@3D-G composite was successfully synthesized by a phosphating process that involved octahedral particles of Sb/SbPO4 with diameters of about 200–400 nm. When used for sodium-ion batteries (SIBs), the composite exhibits a capacity of 425.3 mA h g−1 after 100 cycles at 0.1 A g−1. Even at 1 A g−1, it retains a capacity of 350.2 mA h g−1 after 100 cycles. The composite also displays high rate capabilities of 484.4, 438.4, 418, 387.5, 361.3, 323 and 236.1 mA h g−1 at 0.05, 0.1, 0.2, 0.5, 1, 2 and 5 A g−1, respectively. Both its cycling stability and rate performance are superior to those of Sb@3D-G and SbPO4@3D-G materials. In the composite, Sb could provide a high capacity and coulombic efficiency, and SbPO4 could offer excellent conductivity and a stable coulombic efficiency. The unique graphene framework also plays a role in stabilizing the structure and buffering volume expansion. This work may pave the way for obtaining Sb-based composite materials with high electrochemical energy storage performance.