基于锰氧化物的超级电容器电极材料的制备及其电化学性能研究

发布时间：2018-03-18 10:18

本文选题：超级电容器　切入点：锰氧化物　出处：《兰州大学》2017年硕士论文　论文类型：学位论文

【摘要】：为应对能源危机与环境污染等问题,世界各国都致力于超级电容器的开发。锰氧化物材料因为储量丰富、价格低廉、理论比电容大、环境友好等优点得到了超级电容器研究者的广泛关注。本论文采用简单易行的方法制备了两种类型的MnOx电极,并采用多种物理和电化学表征方法研究了它们的结构和电化学性能。主要内容如下:1.水热法制备不同价态和形貌的锰氧化物电极材料及其电化学性能研究在本章节实验中,以高锰酸钾和具有儿茶酚结构的化合物(盐酸多巴胺或3,4-二羟基苯基丙酸)为原料,在不改变其它反应条件的情况下,通过调控二者的摩尔配比,以水热合成的方法制备了一系列不同形貌和晶型的锰类化合物。通过TEM、SEM、XRD和FTIR表征确定了各产物的形貌和晶体结构,分别为纳米花状的δ-MnO_2、棒状的MnOOH、纳米颗粒状的Mn_3O_4、立方形及纺锤形的MnCO_3。将粉末涂覆到集流体上制成电极后,于0.5 M Na2SO_4电解液中研究了它们的电化学性能,结果发现,在5 mV/s的扫描速率下,纳米颗粒状的Mn_3O_4和立方形的MnCO_3的比电容最小,棒状的MnOOH和纺锤形的MnCO_3比电容居中,而纳米花状的δ-MnO_2具有最好的电容性能,其比电容为307.4 F/g。在经过500次充放电循环后,δ-MnO_2能保留56.2%的初始比电容,可以应用到超级电容器中。2.高性能的超级电容器电极材料泡沫镍/二氧化锰的制备及其电化学性能研究在本章节实验中,通过KMnO_4和HAc之间简单的氧化还原反应直接在泡沫镍的表面上负载了MnO_2材料,该复合材料可以直接作为电极使用。通过TEM和SEM表征发现成功负载的MnO_2为相互交联的纳米片状结构,并通过CV和GCD等电化学表征方法研究了该复合材料的电化学性能。泡沫镍/MnO_2复合材料结合了MnO_2的高电容性能、3D多孔泡沫镍的高比表面积和高导电性的优势,使其较之MnO_2粉末电极具有更加优异的电化学性能:较高的比电容(5 mV/s的扫描速率下比电容值高达1095 F/g),较好的倍率性能(即使在100 mV/s的扫描速率下比电容也有499 F/g),较低的内部电阻和良好的循环稳定性(经过1000次充放电循环后能保留54.5%的初始比电容)。
[Abstract]:In order to deal with the problems of energy crisis and environmental pollution, countries all over the world are committed to the development of supercapacitors. In this paper, two types of MnOx electrodes were prepared by a simple and convenient method. The main contents are as follows: 1. The preparation and electrochemical properties of manganese oxide electrode materials with different valence states and morphologies by hydrothermal method were studied in this chapter. Potassium permanganate and catechol-containing compounds (dopamine hydrochloride or 3o 4-dihydroxyphenyl propionic acid) were used as raw materials and their molar ratio was adjusted without changing other reaction conditions. A series of manganese compounds with different morphologies and crystal forms were prepared by hydrothermal synthesis. The morphology and crystal structure of the products were determined by Tem SEM XRD and FTIR. 未 -MnO _ 2 in nanoscale shape, MnOOH in rod shape, Mn3O _ 4 in nano-particle shape, square and spinned-shaped MnCO _ 3s _ 3 respectively. Their electrochemical properties were studied in 0.5m Na2SO_4 electrolyte after the powder was coated on the collector and made into electrode. At the scanning rate of 5 mV/s, nano-granular Mn_3O_4 and square MnCO_3 have the smallest specific capacitance, rod-shaped MnOOH and spindle-shaped MnCO_3 have the middle specific capacitance, while nano-flower-like 未 -MnO2 has the best capacitance. Its specific capacitance is 307.4 F / g. After 500 charge-discharge cycles, 未 -MnO _ 2 can retain an initial specific capacitance of 56.2%. Preparation and Electrochemical Properties of High performance Supercapacitor electrode material Nickel / Manganese dioxide. The MnO_2 material was directly loaded on the surface of nickel foam by a simple redox reaction between KMnO_4 and HAc, and the composite could be used as an electrode directly. It was found by TEM and SEM that the successfully loaded MnO_2 was cross-linked nanoflake structure. The electrochemical properties of the composite were studied by CV and GCD. The nickel foam / MNO _ 2 composite combined the advantages of high capacitance of MnO_2 and high specific surface area and high conductivity of porous nickel foam. It has better electrochemical performance than the MnO_2 powder electrode: the specific capacitance is as high as 1095F / g / g at the scanning rate of 5 mV/s, and the specific capacitance is 499F / g / g (even at the scan rate of #number0# mV/s, the specific capacitance is 49F / g). Low internal resistance and good cycle stability (after 1, 000 charge-discharge cycles, the initial specific capacitance of 54.5% can be retained.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ137.12;TM53

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