基于氧化铁/生物质碳复合材料的高性能超级电容器研究

Study on high-performance supercapacitors based on Fe_(2)O_(3)/biomass carbon composites

为改善碳材料比电容低的问题以及氧化铁(Fe_(2)O_(3))导电性和循环稳定性差的问题,采用氧化铁修饰生物质衍生碳(ATC)表面制备氧化铁/生物质碳(Fe_(2)O_(3)/ATC)复合材料,通过氧化铁和生物质衍生碳的协同效应使复合材料获得更高的比电容和更好的稳定性。利用扫描电镜(SEM)、X射线光电子能谱(XPS)、拉曼(Raman)光谱等技术手段对样品进行了表征。结果表明,制备的复合材料存在一定的孔隙结构,氧化铁纳米粒子被锚定在碳表面。当氧化铁和生物质衍生碳的质量比为1∶1时,制备的复合材料具有最优的电化学性能,在3.0 mol/L氢氧化钾溶液中显示出430.8 F/g(电流密度约为1.0 A/g)的高比电容,电流密度增大20倍时电容保持率大于60%。将其作为负极构建的不对称超级电容器具有较高的电压窗口(0~1.6 V),并且实现了39.1 W·h/kg的高能量密度;同时表现出优异的循环稳定性,在电流密度为10 A/g下循环5000次后拥有111%的电容保持率。

To improve the low specific capacitance of carbon materials as well as the poor electrical conductivity and low cyclic stability of ferric oxide(Fe_(2)O_(3)),Fe_(2)O_(3) was used to modify the surface of biomassderived carbon to prepare Fe_(2)O_(3)/biomass carbon composites,which achieved higher specific capacitance and better stability by the synergistic effect of Fe_(2)O_(3) and biomass-derived carbon.The samples were characterized by scanning electron microscopy(SEM)、X-ray photoelectron spectroscopy(XPS)and Raman spectra.The results demonstrated that the prepared composites had a certain pore structure,with Fe_(2)O_(3) nanoparticles anchored on the carbon surface.When the mass ratio of Fe_(2)O_(3) and biomassderived carbon was 1∶1,the prepared composites possessed the best electrochemical performance,showing a high specific capacitance of 430.8 F/g(1.0 A/g)in 3.0 mol/L KOH.The capacitance retention was still greater than 60%when the current density was increased by 20 times.The asymmetric supercapacitor constructed by using it as the negative electrode had a high voltage window(0~1.6 V)and achieved a high energy density of 39.1 W·h/kg.While,it also exhibited excellent cycling stability with 111%capacitance retention after 5000 cycles at 10 A/g.