High capacity-favorable tap density cathode material based on three-dimensional carbonous framework supported Na3V2(PO4)2F3 nanoparticles

- NVPF nanoparticles are supported by 3D carbonous framework with low carbon content.
- Favorable tap-density and low specific surface area.
- Excellent high-rate capacity and good cycling performance.
- Simple technical procedure and wide universality.

NASICON structured Na3V2(PO4)2F3/C@RGO (NVPF/C@RGO) composites with interconnected 3D carbonous framework are composed of NVPF nanoparticles, coating layer of amorphous carbon and RGO nanosheets, where the RGO serves as the main framework. The low carbon content (4.6%) and uniform NVPF nanoparticles supported by the unique 3D carbonous architecture lead to low specific surface area and favorable tap density. By taking full advantage of the interconnected 3D carbonous framework, the excellent electronic conductivity of NVPF/C@RGO is three orders of magnitude higher than that of pristine NVPF/C, resulting in favorable enhanced electrochemical performance. The initial capacity of 124.5 mAh g−1 at 0.1 C-rate and a high discharge capacity of 119.2 mAh g−1 with an excellent retention of 90.9% after 700 cycles at 1 C can be attained. Most importantly, NVPF nanoparticles connected with 3D carbonous framework have a low specific surface area, favorable tap density, simple technical procedure, and show great potential to optimize battery performance, apply in large scale energy storage and extend to all polyanion-based cathode materials.