应用水热合成法制备NaV2O5晶体,XRD、SEM、拉曼光谱和XPS分析测试及电化学表明,该材料属正交晶系,空间群为Pmmn,呈纯相的棒状结构,长度约有20μm,宽度大约200 nm.该材料的V离子均价为+4.5价.首次放电容量达到120 mAh/g,放电平台为2.0 V.经过20个循环,容量保持率98 mAh/g,表现了良好的循环性能.

The NaV2O5 was prepared by a low temperature hydrothermal process.The material crystallized in the layered orthorhombic structure with space group Pmmn.X-ray diffraction confirmed that the material was pure and the scanning electron microscopy showed that the material was composed of needle crystals with 20 μm in length and 200 nm in width.X-ray photoelectron spectroscopy indicated the co-existence of V4+ and V5+ in the material,which results in an average V4.5+ oxidation state of the material.The observed Raman bands were ascribed to different V—O vibrations.The first specific capacity about 120 mAh/g between 3.5 V and 1.0 V with a voltage plateau at 2.0 V was obtained,and the specific capacity was still 98 mAh/g after 20 cycles,which shows the good electrochemical stability of the material.