Hollow NaTi_1.9Sn_0.1(PO₄)₃@C Nanoparticles for Anodes of Sodium-Ion Batteries with Superior Rate and Cycling Properties

Herein, two strategies are simultaneously used to synthesize the hollow carbon-coated nanoparticles of NaTi_1.9Sn_0.1(PO₄)₃@C (NTSP@C). The porous morphology of NTST@C is controlled through a trace amount of tin doping while selecting a fire-new carbon source. The NTSP@C materials present a nanosized structure with a hollow morphology, exhibiting a large specific surface area of ≈71.0 m² g⁻¹ and a average bore diameter of ≈26.4 nm. Moreover, the carbon layer is ≈5 nm thick with a mass ratio of 6.81%. The NTSP@C sample displays an ultrastrong rate capability (128.8 mA h g⁻¹ at 0.1 C and 101.5 mA h g⁻¹ at 10 C at 1.5–3.0 V) and a superior cycling performance (126.3–115.8 mA h g⁻¹ after 300 cycles at 1 C for a retention ratio of 91.7% and 101.4–87.1 mA h g⁻¹ after 2000 cycles at 10 C for a retention ratio of 85.9%). These excellent electrochemical performances are due to the nanosized structure, unique morphology, and thin carbon layer as a conductive medium. It is clear that the NTSP@C material is a promising anode material that can be incorporated into sodium-ion batteries to achieve superior electrochemical performance.