Interface-Controlled Rhombohedral Li₃V₂(PO₄)₃ Embedded in Carbon Nanofibers\nwith Ultrafast Kinetics for Li-Ion Batteries

Abstract

We present a unique\ncomposite assembly of rhombohedral Li₃V₂(PO₄)₃ and carbon nanofiber, which\nsimultaneously facilitates Li-ion transport as well as electron transfer.\nFor the synthesis of this composite, the inorganic precursors were\nconfined in electron-spun nanofibers, and then, through controlled\nannealing, Na₃V₂(PO₄)₃ particulates were grown with controllable crystallite size and partially\nembedded into carbon nanofibers with precisely controlled diameter.\nThe rhombohedral Li₃V₂(PO₄)₃ could be successfully obtained by ion exchange from Na to Li in\nthe prepared Na₃V₂(PO₄)₃. The final rhombohedral Li₃V₂(PO₄)₃ particles anchored onto the carbon nanofibers exhibited\nexcellent electrochemical performance with fast kinetics for Li-ion\nbatteries. Suprisingly it maintains 69 and 41 mAh/g even at 100<i>C</i> as cathode and anode. Several advanced characterizations\nrevealed that its ultrafast kinetics could be attributed to synergistic\neffect resulting from the distinctive microstructure of the composite\nand the structural superiority of highly symmetric rhombohedral Li₃V₂(PO₄)₃ over its monoclinic\nhomologue for Li-ion transport.