三维有序大孔α-Fe2O3的制备及电化学性能研究

通过聚苯乙烯(PS)胶晶模板法合成了三维有序大孔(3DOM) α-Fe2O3, 运用扫描电镜、热重分析、X射线衍射、电化学充放电等多种方法对其结构和性能进行了表征和研究. SEM表明PS 胶晶模板和3DOM α-Fe2O3呈周期性排列. 合成的3DOM α-Fe2O3为三维有序多孔网状结构, 具有球型和六边形的孔隙形貌, 其孔径大小约为(115±10) nm; 孔壁由α-Fe2O3纳米晶粒组成, 壁厚为20～30 nm. XRD图谱表明经过煅烧除去模板后, 形成了纯α-Fe2O3相. 当3DOM α-Fe2O3作为锂离子电池负极材料时, 首次放电充电容量分别高达1880和1130 mAh•g－1, 20次循环后可逆容量依然高达631 mAh•g－1, 库仑效率大于90%.

Fabrication and Electrochemical Properties of Three-dimensionally Ordered Macroporous α-Fe2O3

Three-dimensionally ordered macroporous (3DOM) α-Fe2O3 was synthesized by using polystyrene (PS) colloidal crystal as templates. The character of 3DOM α-Fe2O3 was measured by scanning electron microscopy (SEM), thermogravimetry (TG), X-ray diffraction (XRD) and electrochemical measurements. SEM images showed that the PS colloidal crystal template and the 3DOM α-Fe2O3 were arrayed periodically in face. The synthesized 3DOM α-Fe2O3 microparticles were composed of sphere or hexagonally porous morphologies interconnected through thin walls formed by nanocrystals of α-Fe2O3. The macropore diameters of the 3DOM α-Fe2O3 were about (115±10) nm and the pore wall thicknesses were between 20～30 nm. X-ray diffraction indicated that a pure α-Fe2O3 phase was produced after calcination. When the 3DOM α-Fe2O3 microparticles were used as anode materials for lithium ion batteries, they exhibited extraordinarily high initial discharge and charge capacities of 1880 and 1130 mAh•g－1 respectively. After 20th cycle, their reversible capacity could be as high as 631 mAh•g－1, with a coulombic efficiency of ＞90%.