Facile synthesis of nitrogen-doped carbon derived from polydopamine-coated Li3V2(PO4)3 as cathode material for lithium-ion batteries

Abstract

Nitrogen-doped, carbon-coated Li₃V₂(PO₄)₃ cathode materials were prepared by the oxidative self-polymerization of dopamine on the Li₃V₂(PO₄)₃ surface and subsequent carbonization of polydopamine. Field emission scanning electron microscopy (FESEM), scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDS) and X-ray photoelectron spectroscopy (XPS) were performed to characterize morphologies and structures. The uniform nitrogen-doped, carbon coating provided a continuous electronic conducting network. Furthermore, the existence of nitrogen in the composite can improve electronic conductivity. As cathode materials for lithium-ion batteries, the nitrogen-doped, carbon-coated Li₃V₂(PO₄)₃ composites display superior rate performance and excellent cycle performance over the pristine Li₃V₂(PO₄)₃ and carbon-coated Li₃V₂(PO₄)₃. The electrode delivers high specific capacity of 74 mA h g⁻¹ at 10 C, and still remains at 95.4% of initial capacity after 100 cycles at 1 C.