溶液燃烧法制备纳米Fe_2O_3/C超级电容器电极材料

Preparation of nano-scale Fe_2O_3/C for electrode material of super-capacitor by solution combustion method

以硝酸铁[Fe（NO3）3·9H2O,氧化剂]、柠檬酸（C6H8O7·H2O,燃料）和硝酸铵（NH4NO3,助燃剂）为原料,在空气气氛下采用溶液燃烧法（350℃,30min）一步合成纳米Fe2O3/C复合材料。研究发现,通过改变柠檬酸的用量可以引入原位碳及改变产物中Fe2O3相的组成。运用X射线衍射（XRD）、热重（TG）、SEM和TEM技术对产物的形貌和结构进行表征,通过循环伏安和恒电流充放电测试研究了Fe2O3/C纳米复合材料的电化学性能。结果表明：Fe2O3/C产物中,Fe2O3为α-Fe2O3和γ-Fe2O3的混合相,当硝酸铁和柠檬酸的摩尔比为6∶8时,合成的产物具有较大的比表面积和孔结构,原位碳均匀分布在Fe2O3纳米颗粒的周围;在1mol/L KOH溶液中,电位窗口-1-0V（vs.SCE）时,Fe2O3/C电极表现出良好的倍率和循环特性（1000次循环后,容量保持率为80.7%）,在电流密度为1A/g时,其比电容为148.4F/g。

Nanostructured Fe2O3/C composites were prepared by one-step solution combustion route （within 30 min at 350℃ in air） from Fe（NO3）3·9H2O solution （oxidizer） with citric acid （fuel） and Ammonium nitrate （combustion improver）. Significantly,in-situ formed carbon could be introduced into the products （i. e. , Fe2O3/C nano-composites） and composition in the Fe2O3 phase by simply increasing the dosage of citric acid in the precursor solution. The morphology and structure characterization of samples were analyzed by X-ray diffraction（XRD）, thermal gravity （TG）, scanning electron microscopy （SEM） ,transmission electron microscopy （TEM）. Cyclic voltammetry and galvanostatic charge/discharge were used to characterize the electrochemical performance of samples. The results showed the Fe2 Oa phase in the Fe2O3/C corn posites was composed of α-Fe2O3 and γ-Fe2O3. When the molar ratio of Fe（NO3）3·9H2O and citric acid was 6：8, the as prepared Fe2O3/C nano-composite had relatively high specific surface areas and mesopores. Besides, in-situ formed carbon was evenly distributed around Fe2O3 nanopartieles. In an electrolyte of 1mol·L^-1 KOH,it exhibited good rate capability and long-term cycling stability （kep over 80.7% of the initial specific capacitance after 1000 cycles） in the potential region of -1-0V（vs. SCE）. At a current density of 1A·g^1,it had a specific capacitance of 148.4F·g^-1.