基于锰、钼氧化物及其复合纳米材料的储能器件研究

发布时间：2019-05-24 06:49

【摘要】：超级电容器也称为电化学电容器,是一种近年来发展迅速的新型能量存储器件。相对于电池而言,超级电容器具有高功率密度、快速充放电、长使用寿命和高安全性等优点,在电动汽车、信息技术、航空航天、清洁能源的开发和利用等诸多领域,有着广阔的应用前景。超级电容器所采用的结构布局和电极材料,在很大程度上决定了器件的性能,是整个器件设计的核心。以结构布局来分,超级电容器分为对称结构和非对称结构两种；以电极材料来分,主要有采用以碳材料为代表的双电层电容器、采用以过渡金属氧化物为代表的赝电容器和二者皆用的混合型电容器。相对而言,后两种电容器在大规模应用方面尽管还有一些瓶颈有待突破,但它们有更大的能量密度,是超级电容器在近来的一个重要发展方向。因此,本论文以后面两种类型的超级电容器为研究重点。本文选定化学性能稳定、高比表面积的活性炭、碳纳米管,廉价且环境友好的二氧化锰、三氧化钼作为超级电容器的电极材料,并与有机导电高分子材料聚吡咯进行复合,结合多种材料表征测试方法,系统地研究了超级电容器结构的优化设计、电极材料的制备、电解液的选择、器件的性能和影响因素等。主要的研究内容和创新点如下： 1.在单根碳纤维基底上,用电化学恒电压法生长了二氧化锰纳米片,并在二氧化锰纳米片外原位生长聚吡咯薄膜进行包覆,研究其电化学性能。结果表明,得到的二氧化锰纳米片属于￡型二氧化锰,且酸性电解质能腐蚀未包覆的二氧化锰纳米片；当￡型二氧化锰包覆聚吡咯薄膜后,可以防止酸性电解质的腐蚀。在恒电压下生长15分钟的二氧化锰纳米片,且经2分钟的聚吡咯生长包覆后,复合材料有良好的电化学性能。这种复合材料构建的超级电容器,工作电压窗口为0～0.8V,在0.1mA cm-3的电流密度下,器件的体积电容可以达到69.3F cm-3；经1000次循环测试,器件能够保留86.7%的初始电容量。在此基础上开发出与微纳机电系统和柔性电子器件相匹配的对称结构固态柔性超级电容器。 2.在碳布基底上,用电化学恒电流法生长了二氧化锰纳米片,并在二氧化锰纳米片外原位生长聚吡咯包覆薄膜,研究其电化学性能。该方法合成的二氧化锰纳米片,经过检测证明其属于水钠锰矿。在碳布基底上,在恒电流下生长75分钟的二氧化锰纳米片,经过2.5分钟的聚吡咯生长包覆后,作为超级电容器的正极,与碳布基底包覆活性炭负电极匹配后,组成非对称结构超级电容器,工作电压窗口为0～1.8V。在0.5mA cm-2的电流密度下,器件的面电容可以达到1.41F cm-2,经1000次循环测试,器件能够保留98.6%的初始电容量。在此基础上,成功开发出与可穿戴式电子设备匹配的非对称结构固态柔性超级电容器。 3.采用过渡金属氧化物中,具有最大功函数差的二氧化锰和三氧化钼作为非对称结构超级电容器的正、负电极材料。用水热法合成二氧化锰纳米线和三氧化钼纳米带,分别掺入一定比例的碳纳米管来改善电极的导电性能。研究表明,由这两种电极构成的非对称超级电容器,工作电压窗口为0～2.0V,在2mV s-1的扫描速度下,其体积比电容为50.2F cm-3。进一步在正、负电极之间插入内联结构的中间层后,器件的工作电压窗口可以达到0～4.0V,当功率密度为261.4mW cm-3时,该电容器的能量密度达到28.6mWh cm-3。经10,000次循环测试,器件能够保留99.6%的初始电容量。
[Abstract]:The super-capacitor, also known as an electrochemical capacitor, is a new type of energy storage device that has developed rapidly in recent years. Compared with the battery, the super capacitor has the advantages of high power density, quick charge and discharge, long service life and high safety, and has wide application prospect in the fields of electric automobile, information technology, aerospace, clean energy development and utilization. The structure layout and the electrode material used by the super capacitor determine the performance of the device to a great extent, which is the core of the whole device design. According to the structure layout, the super-capacitor is divided into two types: the symmetrical structure and the non-symmetrical structure, and the electrode material is divided into two electric double layer capacitors represented by the carbon material, and the pseudo-capacitor represented by the transition metal oxide and the mixed type capacitor are used. In contrast, the latter two kinds of capacitors have to break through the large-scale application, but they have a greater energy density, which is an important development direction of the super-capacitor in recent years. Therefore, this paper focuses on two types of supercapacitors. The method comprises the following steps of: selecting active carbon with stable chemical property, high specific surface area, carbon nano-tube, cheap and environment-friendly manganese dioxide and ferrosilicon as the electrode material of the super capacitor, The optimum design of the super capacitor structure, the preparation of the electrode material, the selection of the electrolyte, the performance of the device and the influencing factors are systematically studied. The main research and innovation points are as follows: 1. on a single carbon fiber substrate, a manganese dioxide nanosheet is grown by an electrochemical constant voltage method, and the polyelectrolyte film is grown in situ outside the manganese dioxide nanosheet to be coated, and the electrochemical property thereof is studied. The results show that the obtained manganese dioxide nanosheet belongs to the manganese dioxide, and the acid electrolyte can corrode the uncoated manganese dioxide nanosheet. When the manganese dioxide nano-sheet is coated with the polyelectrolyte thin film, the corrosion of the acidic electrolyte can be prevented. Etching. The composite material has good electrochemical property after 15 minutes of manganese dioxide nanosheet is grown at constant voltage and the composite material is coated with a 2-minute polyelectrolyte. The super-capacitor constructed by the composite material has a working voltage window of 0-0.8V, and the volume capacitance of the device can reach 69.3 F-3 under the current density of 0.1 mA-3; and the device can retain 86.7% of the initial capacitance after the 1000-cycle test on the basis of which, a symmetrical structure solid-state flexible super capacitor matched with the micro-nano electromechanical system and the flexible electronic device is developed 2. on the carbon cloth substrate, the manganese dioxide nanosheet is grown by an electrochemical constant current method, The method is characterized in that the manganese dioxide nanosheet synthesized by the method is tested to prove that the manganese dioxide nanosheet belongs to water, the manganese dioxide nanosheet is grown at constant current for 75 minutes on a carbon cloth substrate, Capacitor, working voltage window is 0 ~ 1 .8 V. The surface capacitance of the device can reach 1.41 F cm-2 at a current density of 0.5 mA cm-2, and the device can retain 98.6% of the initial capacitance after 1000 cycles. On the basis of this, it has successfully developed the non-symmetrical structure solid-state flexible super-fine structure matched with the wearable electronic equipment. 3. using the transition metal oxide, the manganese dioxide with the greatest work function difference and the manganese dioxide are used as the positive part of the super-capacitor of the asymmetric structure, The negative electrode material is synthesized by hydrothermal synthesis of the manganese dioxide nano-wire and the conductive nano-band, and the carbon nano-tube with a certain proportion is respectively doped to improve the electrode. The study shows that the working voltage window is 0-2.0V, and the volume ratio of the asymmetric super capacitor is 50.2 at the scanning speed of 2 mV s-1. The working voltage window of the device can reach 0-4.0V, when the power density is 261.4 mW cm-3, the energy density of the capacitor reaches 28.6 mW. h cm-3. After 10,000 cycles, the device will be able to retain 99.6%
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TM53;TB383.1

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