▎ 摘　　要

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/Gmaterial 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.