On the possibility of polystyrene-derived carbon coating for NASICON-type Na3V2(PO4)3 composites as cathode materials for sodium-ion batteries

摘要

We here prepared polystyrene-derived carbon-coated Na₃V₂(PO₄)₃ composite (NVP/C) cathode materials via a solid-phase reaction using a mixture of NVP precursor and polystyrene (as the carbon source), followed by calcination at high temperatures. Using this method, we were able to obtain active NVP materials with relatively high purity while allowing a uniform surface coating with carbon layers about 3–4 nm thick. This structure significantly prevented NVP particle growth even after calcination at high temperatures. The NVP/C material calcined at 700°C exhibited the best charge–discharge performance among the samples studied.