Carbon-coated LiFePO_4 hollow nanofibers as cathode materials for Li-ion batteries were obtained by coaxial electrospinning. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller specific surface area analysis, galvanostatic charge–discharge, and electrochemical impedance spectroscopy(EIS) were employed to investigate the crystalline structure, morphology, and electrochemical performance of the as-prepared hollow nanofibers. The results indicate that the carbon-coated LiFePO_4 hollow nanofibers have good long-term cycling performance and good rate capability: at a current density of 0.2C(1.0C = 170 mA ·g^(-1)) in the voltage range of 2.5–4.2 V, the cathode materials achieve an initial discharge specific capacity of 153.16 mA h·g^(-1) with a first charge–discharge coulombic efficiency of more than 97%, as well as a high capacity retention of 99% after 10 cycles; moreover, the materials can retain a specific capacity of 135.68 mA h·g^(-1), even at 2C.
Metal oxide(TiO2or Co3O4)doped activated carbon nanofbers(ACNFs)were prepared by electrospinning.These nanofbers were characterized by X-ray difraction(XRD),scanning electron microscopy(SEM),and BrunnerEmmett-Teller method(BET).The results show that the average diameters of ACNFs were within the range of 200-500nm,and the lengths were several tens of micrometers.The specifc surface areas were 1146.7 m2/g for TiO2-doped ACNFs and 1238.5 m2/g for Co3O4-doped ACNFs,respectively.The electrospun nanofbers were used for adsorption of low concentration sulfur dioxide(SO2).The results showed that the adsorption rates of these ACNFs increased with an increase in SO2concentration.When the SO2concentration was 1.0μg/mL,the adsorption rates of TiO2-doped ACNFs and Co3O4-doped ACNFs were 66.2%and 67.1%,respectively.The adsorption rate also increased as the adsorption time increased.When the adsorption time was 40 min,the adsorption rates were 67.6%and 69.0%for TiO2-doped ACNFs and Co3O4-doped ACNFs,respectively.The adsorption rate decreased as the adsorption temperature increased below 60 C,while it increased as the adsorption temperature increased to more than 60 C.
采用同轴静电纺丝法制备了碳包覆纳米SnO2中空纤维超级电容器电极材料.利用X射线衍射(XRD)、拉曼光谱、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和比表面积分析仪(BET)对材料进行表征.结果表明,纤维呈现中空形貌,平均直径为1μm;SnO2颗粒均匀分布于碳壳结构中,平均粒径为3–15 nm.材料的比表面积为565 m2 g–1.在三电极体系中,当电流密度为0.25 A g–1时,电极材料的比容量达397.5 F g–1;在1.0A g–1电流密度下,充放电循环3000次后比容量仍保持为初始值的88%.在对称型双电极体系中,电流密度为0.25 A g–1时,电极材料的比容量达162.0 F g–1,在1.0 A g–1电流密度下,充放电循环3000次后比容量仍保持为初始值的84%.
采用静电纺丝法制得La2Co Fe O6竹节状中空纳米纤维光催化材料。La2Co Fe O6纳米纤维具有稳定的一维结构,由菱形晶型的La2Co Fe O6纳米颗粒相互连接组成,并存在明显的竹节状中空结构,其比表面积可达98.7 m2/g。La2Co Fe O6纳米纤维对自然光具有较高的利用率,其禁带宽度为1.6 e V。在甲基橙溶液浓度为10 mg/L,p H为2,催化剂用量为1.5 g/L条件下,自然光光照2 h后,La2Co Fe O6纳米纤维对甲基橙的降解率可达96.9%。
