| 초록 |
In this study, Sodium-Super-Ionic-Conductor (NASICON) of Na3V2(PO4)2F3 (NVPF)/C cathode for sodium-ion batteries is prepared successfully by convenient polyol refluxing process without any impurity phases. The NVPF has a tetragonal NASICON-type lattice with a space group of P42/mnm, as confirmed by X-ray diffraction and Rietveld refinement. In this method, polyol is used a solvent as well as a carbon source. The presence of nanosized NVPF particles in the carbon matrix is confirmed by high-resolution transmission electron microscopy (HR-TEM) and field-emission scanning electron microscopy (FE-SEM). The carbon is analyzed by Raman scattering and elemental analysis. When applied as a Na-storage material in a potential window of 2.0–4.3 V, the electrode exhibits two plateaus at 3.7 and 4.2 V with an electrochemically active V3+/V4+ redox couple. In addition, after Na3V2(PO4)2F3/C was cycled about 1,500 at 15C, It maintaion capacity of ~ 88%. Moreover, at high current densities of 30 and 50 C, Na3V2(PO4)2F3/C cathode retains the specific discharge capacities of 108.4 and 105.9 mAh·g–1, respectively, the structural stability of the material prepared through a facile polyol refluxing method. |
