MoO_3纳米纤维电极材料的水热合成和电化学表征

Hydrothermal synthesis of MoO_3 nanobelts and their electrochemical characterization

通过调控硝酸浓度，利用水热酸化钼酸盐溶液高产率地合成了的α-MoO3纳米纤维。并用X射线衍射（XRD）、透射电子显微镜（TEM）和高分辨透射电镜（HRTEM）等技术对其形貌和结构作了表征。结果表明，当硝酸浓度〉6．73mol／L时，可制备出直径范围在50-400nm，沿[001]方向生长的正变相α-MoO3纳米纤维；硝酸浓度在2．6mol／L左右时，产物是针状的六方相MoO3；随着硝酸浓度的提高，产物由六方相MoO3向正交相MoO3过渡。对正交MoO3纳米纤维电极材料的电化学充放电测试表明，电流密度从0．195mA／cm^2增至0．52mA／cm^2时，首次锂插入容量降幅比通常的微米级粉体材料要小。

α-MoO3 nanobelts can be hydrothermally synthesized by acidifying solution of molybdate with nitric acid at a well-controlled concentration. X-ray diffraction,transmission electron microscopy （TEM） and high-resolution transmission electron microscopy （HRTEM） were employed to analyze the crystalline structure and morphology of the synthesized MoO3 nanofibres. The results indicate that orthorhombie MoO3 nanofibres with widths ranging from 50-400nm grow along [001-] direction when nitric acid concentration is above 6. 3mol/L, while hexagonal MoO3 can be obtained when nitric acid concentration is around 2.6mol/L, Galvanostatie cycling tests reveal that electrode composed of MoO3 nanobelts shows smaller decline in first lithiation capacity than that consists of mierosized MoO3 powders when the current density increases from 0.195-0.52mA/cm^2.