Porous Na3V2(PO4)3@C nanoparticles enwrapped in three-dimensional graphene for high performance sodium-ion batteries

Abstract

Porous Na₃V₂(PO₄)₃@C nanocomposites enwrapped in a 3D graphene network were prepared using a simple freeze-drying-assisted thermal treatment method. The carbon layer and 3D graphene network provide not only a 3D conductive network but also a double restriction on the aggregation of Na₃V₂(PO₄)₃ particles that have a high crystallinity under high temperature treatment. Due to the high electrochemical activity of the highly crystalline Na₃V₂(PO₄)₃ nanoparticles and 3D conductive network, the novel NVP@C/G material displays a superior rate capability (76 mA h g⁻¹ at 60C) and ultra-long cyclability (82% capacity retention for 1500 cycles at 40C) when used in sodium-ion batteries.