Monoclinic Li3V2(PO4)3/C nanocrystals co-modified with graphene nanosheets and carbon nanotubes as a three-dimensional-network cathode material for rechargeable lithium-ion batteries

Abstract

A graphene nanosheet and carbon nanotube co-modified Li₃V₂(PO₄)₃/C composite has been first prepared via a hydrothermal-assisted sol–gel method. The crystal structure, morphology and electrochemical performance of the as-prepared sample are studied in detail. In this material, the Li₃V₂(PO₄)₃/C (100–150 nm) nanoparticles are strongly adhered to the surface of the graphene nanosheets while the carbon nanotubes are embedded into the Li₃V₂(PO₄)₃/C and graphene nanosheets, and both carbon additives have interlaced to form a crosslinked three-dimensional (3D) mixed conducting network. Thus, the composite exhibits a remarkably high rate capability and long cycle stability, delivering an initial discharge capacity of 147.5 mA h g⁻¹ at 20C within a voltage range of 3.0–4.8 V and the capacity retention is 82.7% after 2000 cycles. With a desirable cell performance, this approach offers a new idea in design and preparation of electrode materials for lithium-ion batteries.