In-situ constructing Na3V2(PO4)2F3/carbon nanocubes for fast ion diffusion with high-performance Na+-storage

Abstract

Due to its beneficial advantage in energy density, Na3V2(PO4)2F3 (NVPF) gains tremendous attentions as cathode material for sodium ion batteries (SIBs). Herein, a delicate nanocube-like architecture that, the thin carbon layers are in-situ formed and coated on NVPF (NVPF-NC), is proposed and fabricated via a modified solid-state synthesis approach, where paraffin associated with surfactants can serve as the quasi-water-in-oil media to confine the growth of nanoparticles. The as-prepared NVPF-NC delivers outstanding rate tolerance (107.7 mAh g−1 at 30C) and superior cyclic stability (capacity preservation of 84.8% after 2500 cycles at 50C). Even assembled in NVPF-NC || hard carbon full cell, NVPF-NC maintains 98.5% of its initial capacity at 0.5C after 100 cycles. Such encouraging achievements should be ascribed to the structural engineering in nanoscale which constructs the rapid Na+-migration paths and the in-situ carbon coating which promotes the electron transport. Therefore, this modified solid-state method enlightens the exploration and rational design for nanosized cathode materials with enhanced electrochemical properties.