Core−Shell Li₃V₂(PO₄)₃@C Composites as Cathode Materials for Lithium-Ion Batteries

Core−shell Li 3 V 2 (PO 4 ) 3 @C nanostructured composites were prepared via a sol−gel route followed by hydrothermal treatment. XRD patterns showed that Li 3 V 2 (PO 4 ) 3 has a monoclinic structure with space group P 2 1 / n . TEM images exhibited that Li 3 V 2 (PO 4 ) 3 particles are encapsulated with a carbon shell ∼10 nm in thickness. Compared with pure Li 3 V 2 (PO 4 ) 3, core−shell Li 3 V 2 (PO 4 ) 3 @C composites presented enhanced electrochemical Li ion intercalation performances. Cyclic voltammetry and electrochemical impedance spectroscopy disclosed that carbon shells improved Li ion diffusion and electrical conductance significantly and also retarded formation of solid electrolyte interphase film of Li 3 V 2 (PO 4 ) 3 cathode materials.