Carbon-coated Li₃V₂(PO₄)₃ derived from metal-organic framework as cathode for lithium-ion batteries with high stability

Recently, Metal-Organic Frameworks (MOFs) derived carbon-based materials have attract wide interest in electrochemical devices due to their large surface area and favorable conductivity. In this work, instead of using MOFs for direct carbon sources, we employed vanadium metal-organic framework (MIL-101(V)) precursor as both carbon sources and vanadium sources for synthesizing carbon-coated Li₃V₂(PO₄)₃ nanocomposites (LVP@M-101). The electrochemical property of LVP@M-101 has been investigated as cathode electrode at a voltage of 3.0–4.8 vs Li⁺/Li, to compare with Li₃V₂(PO₄)₃ prepared using V₂O₅. It is shown that the composite material displays a remarkably improved electrochemical stability with a high reversible capacity of 113.1 and 105.8 mA h g⁻¹ at the rate of 0.5C and 1C after 1000 cycles, together with a superior rate performance at various current densities from 0.1C to 10C. Moreover, we have applied ex-situ PXRD and EPR spectroscopy to investigate the lithiation/delithiation process of LVP@M-101 electrode. Through detailed characterizations and electrochemical tests, we believe that the novel nanocomposites LVP@M-101 retain the two-phase transition nature of Li₃V₂(PO₄)₃ and the enhanced cathodic performance in lithium-ion battery is largely due to its unique structural stability.