Ultrafast Cathode Characteristics of Nanocrystalline-Li₃V₂(PO₄)₃/Carbon Nanofiber Composites

Anisotropically grown Li 3 V 2 (PO 4 ) 3 nanocrystals, which are highly dispersed and directly impregnated on the surface of a carbon nanofiber (CNF), were successfully synthesized via a two-step synthesis process: i) precipitation of nanoplated V 2 O 3 precursors (20–200 nm); ii) transformation of the V 2 O 3 precursor into Li 3 V 2 (PO 4 ) 3 nanoplates without size change. The direct attachment of the Li 3 V 2 (PO 4 ) 3 nanocrystals to the carbon surface improves the electronic conductivity and Li + diffusivity of the entire Li 3 V 2 (PO 4 ) 3 /CNF composite, simultaneously producing a mesoporous network (pore size of approximately 10 nm) that acts as an electrolyte reservoir owing to the pillar effect of the impregnated Li 3 V 2 (PO 4 ) 3 crystals. This ideal Li 3 V 2 (PO 4 ) 3 /CNF nanostructure enabled a 480C rate (7.5 seconds) discharge with 83 mA h g −1 , and 69% of capacity retention at the slowest discharge rate (1C). Such an ultrafast charge–discharge performance opens the possibility of using Li 3 V 2 (PO 4 ) 3 as a cathode material for ultrafast lithium ion batteries with a stable cycle performance over 10,000 cycles at a 10C rate, maintaining 85% of the initial capacity.