Uniform Carbon Coated Na3V2(PO4)2O2xF3-2x Nanoparticles for Sodium Ion Batteries as Cathode

A uniform carbon-coated Na3V2(PO4)(2)O2xF3-2x (NVPOF/C) nano-particle synthesized by a novel pyro synthesis method is utilized for sodium-ion batteries (SIBs) as a cathode. Remarkably, the electrochemical properties are performed at high rates show significantly improved discharge capacity. At 0.1 degrees C, the NVPOF/C cathode shows a discharge capacity of 130 mAh g(-1), corresponding to 100% of the theoretical capacity. Even at 50 degrees C, a discharge capacity of similar to 85 mAh g(-1) could be attained. The in situ X-ray diffraction and ex-situ synchrotron X-ray absorption near edge structure spectroscopy results exposed that the reversible sodium ion insertion/extraction into/from NVPOF/C host structure occurs with a small volume change (3.4%), indicating the structural stability of the cathode. Our study validates that the Na3V2(PO4)(2)O2xF3-2x/C electrode is a promising candidate for developing high power/energy density cathodes for SIBs.