循环伏安法制备石墨-MnO_2复合电极及其特性分析

Preparation of Graphite-MnO_2 Composite Electrode Using Cyclic Voltammetry Method and Evaluation of Its Property

MnO_2是一种广泛用于制作超级电容的重要材料,电化学方法制备的电极材料具有组织均匀等优点。为了提高石墨基体上电沉积的MnO_2的电容值,以硫酸锰和硫酸钠为主要原料,采用循环伏安法在石墨基体上制备MnO_2膜层,采用扫描电子显微镜(SEM)、能谱(EDS)等研究了扫描速率、扫描次数以及添加硫酸镍对MnO_2膜层电容特性的影响。结果表明:随着扫描次数的增加,MnO_2膜层的电容先增加后下降,随着扫描速率的增大,MnO_2沉积速率先增大后减小,当扫描次数为550次、扫描速率为0.14 V/s时,获得的MnO_2颗粒均匀细小,膜层具有最大的电容;当溶液中硫酸镍与硫酸锰比例为1∶15时,膜层中沉积了MnO_2和NiO,颗粒均匀细小,增大了膜层的电容量。

In order to improve the capacitance value of the deposited MnO_2 film on graphite substrate,using MnSO_4 and Na_2SO_4 as raw materials,the MnO_2 film was prepared by cyclic voltammetry method on graphite substrate.Subsequently,scanning electron microscopy(SEM) and energy dispersive X-ray spectrometer(EDS) were used to characterize the influences of scanning speed,number of times and nickel sulfate on the capacitance characteristics of MnO_2 film.Results showed that with the increase of scanning number of times,the capacitance of MnO_2 film increased firstly and then decreased.As the scanning speed became quicker,the deposition rate of MnO_2 increased firstly and then decreased.When the scanning number of times was 550 and the speed was 0.14 V/s,the obtained MnO_2 particle was uniform and tiny,and the film had the optimal capacitance.Besides,when the ratio of nickel sulfate and manganese sulfale was1:15,the uniform tiny MnO,and NiO particles were deposited on the film,which could improve the capacitance.