3V2 (PO4)3/C composites synthesized via a spray drying -assisted process with high-rate performance as cathode materials for sodium-ion batteries]]>

摘要

Abstract Porous spherical Na3V2(PO4)3/C composites were synthesized by a spray drying-assisted approach combined with microwave calcinations, and then characterized as cathode materials for sodium-ion batteries. The effect of carbon content on Na3V2 (PO4)3/C were investigated by X-ray diffraction, scanning electron microscopy, Brunauer–Emmet–Teller method, charge-discharge test, cyclic voltammetry and electrochemical impedance spectra measurements. The results demonstrate that the Na3V2(PO4)3/C composite with 5wt.% carbon exhibits the best electrochemical performance among the as-prepared three Na3V2 (PO4)3/C samples. It delivers the discharge capacity of 97.9mAhg?1, 93.5mAhg?1 at 0.2C and 5C, respectively. Furthermore, 97.9% of its initial capacity is remained after 500 cycles at a high rate of 5C. The superior electrochemical performance can be ascribed to the improvement of electronic and ionic conductivity by carbon coating and porous spherical structure. Highlights ? Na3V2 (PO4)3/C composites are synthesized by spray drying-assisted method. ? Na3V2 (PO4)3/C composites form porous spherical structure. ? Carbon coating and porous spherical structure are favorable for better property. ]]>