【摘要】 以KMnO4和MnCl2.4 H2O为原料,采用液相化学沉淀法合成纳米结构MnO2电极材料,并添加一定量的K2Cr2O7对其进行改性。通过X射线衍射(XRD),扫描电子显微镜(SEM)等手段对MnO2的结构形貌进行表征;利用循环伏安法和恒流充放电等方法研究了MnO2在1 mol/L KOH电解液中的电容行为。测试结果表明,K2Cr2O7的存在导致了MnO2由γ-MnO2向a-MnO2晶型的转变以及MnO2纳米棒的形成。MnO2纳米棒的直径约为80 nm,长度约为0.5~2μm,并且MnO2电极材料的晶化程度和电化学性能都得到了提高。当K2Cr2O7添加量为10%(与KMnO4的质量比)时,在0.3A/g和1 A/g电流密度下,电极比容量分别为271 F/g和199 F/g,大约是未添加K2Cr2O7条件下制备的电极的2倍。Cr掺杂MnO2纳米棒表现出优异的高倍率性能。更多还原

【Abstract】 Nanostructured MnO2 electrode materials were synthesized by chemical co-precipitation method using KMnO4and MnCl2·4 H2O as raw materials.A certain amount of K2Cr2O7 was added for modification.The structure and morphology of MnO2 were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM).The capacitive behaviors of MnO2 were studied by cyclic voltammetry(CV) and galvanostatic charge-diacharge in 1 mol/L KOH electrolyte.The presence of K2Cr2O7 resulted in a structural change from γ-MnO2 to α-MnO2 phase and the formation of MnO2 nanorods whose diameter is about 80 nm and the length is about 0.5~2 μm.Moreover,the improvement of crystallinity and electrochemical performance of MnO2 electrode materials were observed.The MnO2 nanorods which were obtained with 1∶10 mass ratio of K2Cr2O7 to KMnO4 shows the specific capacitance of 271 F/g and 199 F/g at the current density of 0.3 A/g and 1 A/g,respectively.The values are about twice as many as those of MnO2 prepared in the absence of K2Cr2O7.The Cr doped MnO2 nanorods exhibits high rate performance.更多还原