Ti/Mn_((0.8-x))Sn_xIr_(0.2)O_2电极的电容性能研究

Capacitive Properties of Ti/Mn_((0.8-x))Sn_xIr_(0.2)O_2 Electrodes

采用热分解法制备了Ti/Mn_(0.8-x)SnxIr_0.2O_2三元氧化物电极材料。通过扫描电子显微镜,X射线衍射、循环伏安和交流阻抗谱等分析了Ti/Mn_(0.8-x)Sn_xIr_0.2O_2电极材料的组织结构和电容性能。结果表明:随SnO_2含量增加,氧化物涂层中正方结构Mn_3O_4相逐渐减少,正方结构SnO_2相逐渐增加。与锰铱二元氧化物相比,SnO_2的加入可明显改善电极材料在0~0.5 V区间的电流响应,并促进氧化锰活性的发挥,但在一定程度上也抑制了氧化铱的活性。SnO_2的加入也改变了电极材料的电荷转移电阻、弛豫时间常数、以及不同频率下的电容响应速度。相比其它电极材料,Ti/Ir_0.2Mn_0.6Sn_0.2O_2电极材料在低频范围(≤1 Hz)有更好的电容响应和更高的活性,因而获得最高的比电容值。

Ti/Mn0.8-xSnxIr0.2O2 ternary oxide electrode materials were obtained by Pechini sol-gel method. The structure and electrochemical performance of Ti/Mn0.8-xSnxIr0.2O2 electrodes was investigated by scanning electron microscope（SEM）, X-ray diffraction（XRD）, cyclic voltammetry（CV） and electrochemical impedance spectroscopy（EIS）. The results show that with the content of SnO2 increasing, affirmative structure of Mn3O4 phase in Ti/Mn0.8-xSnxIr0.2O2 electrodes oxide coating gradually decreases in amount, but affirmative structure of SnO2 phase increases in amount. Compared with the Mn-Ir-based binary oxides, the addition of SnO2 can significantly improve the current response of electrodes in the range of 0～0.5 V and enhance activity of manganese oxide, but suppress activity of iridium oxide. Impedance analysis indicates that the charge transfer resistance, the relaxation time constant and the capacity of different frequency response of electrode materials change after addition of SnO2. In contrast, the Ti/Mn0.6 Sn0.2 Ir0.2O2 electrode has better capacitance response and higher activity in the low frequency range（≤ 1 Hz）, demonstrating the highest specific capacitance.