电化学和水热沉积法制备膜电极材料及其电化学性能研究

发布时间：2018-01-14 01:20

  本文关键词：电化学和水热沉积法制备膜电极材料及其电化学性能研究　出处：《宁夏大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： 超级电容器 金属有机骨架材料 金属硫化物 电化学合成法 水热法

【摘要】：由于环境的日益恶化、温室效应的加剧和化石燃料的耗尽,发展新能源产业已经迫在眉睫,其中高性能的能量存储和转换材料是关键技术之一。超级电容器因其高功率密度、可快速充放电以及循环寿命长等诸多优点受到了广泛关注。在制备电极材料的过程中通常需要加入粘结剂来增强电极材料与集流体之间的黏附性,但是也会因此而堵塞电极材料的孔道,减少有效孔道面积。为了解决这一问题,本论文利用电化学和水热沉积法分别在泡沫镍和铁片上直接生长制备Ni-MOFs和硫化铁薄膜电极,在无需添加任何粘结剂的情况下,提高了材料的利用率。本文研究了合成工艺参数与电化学性能之间的关系,为进一步优化工艺参数,改进材料性能提供了科学依据。本论文主要包括以下两个方面的研究内容：(1)以泡沫镍为集流体和镍源,均苯三甲酸为配体,蒸馏水和无水乙醇混合溶液为溶剂,氟化铵为电解质,通过电化学合成法在泡沫镍基底上直接生长出Ni-MOFs膜电极材料。研究了不同的电化学合成时间、电流密度、温度和电解液配比对制备Ni-MOFs泡沫镍薄膜电极的影响,利用X-射线衍射(XRD),扫描电镜(SEM)对其进行了结构表征。研究表明,在不单独加入镍源的情况下,可以在泡沫镍孔道中生长一层Ni-MOFs的针状晶体。负载量随电化学时间和电流密度的增加而增加。通过循环伏安法,恒流充放电法和电化学阻抗谱技术测试了该电极材料的电化学性能。结果表明：在扫速为10mV/s时,Ni-MOFs的比电容仅为25.63 F/g。在扫速为10 mV/s下,经过500次循环测试之后电容保持率为63.68%。为了提高材料的比电容,以Ni-MOFs为前驱体,通过高温处理得到了NiOx/C复合材料,研究了不同的热解温度对电极材料性能的影响。Ni-MOFs电极碳化后转化成为Ni/NiOx/C复合电极材料,碳化温度为900℃时,所得Ni/NiOx@C复合材料的电化学性能最佳。在扫速为10 mV/s时,碳化样品的比电容达到224.56 F/g。在扫速为10 mV/s下,经过500次循环测试之后电容保持率为92.83%。优化得到电化学合成的工艺参数为电流密度7 mA/cm2、温度60℃、时间10h和电解液配比为1：1。(2)以铁片作为集流体,FeCl2·4H2O铁源,分别以H2NCSNH2和C2H5NS为硫源,通过水热法在铁片上生长硫化铁薄膜电极材料。研究了不同硫源、铁源浓度、水热温度和水热时间对FeS纳米片生长的影响,并对该电极材料进行结构表征和电化学性能测试。结果表明,以H2NCSNH2为硫源,水热温度在200℃,水热时间在36 h时,合成的FeS纳米片结晶性较好,物相单一。在扫速为10 mV/s下,样品的比电容为66.10 F/g。在扫速为10 mV/s下,经过1000次循环之后,FeS纳米片样品的电容保持率为89.30%。以C2H5NS为硫源,水热温度在165℃,水热时间在36 h时,合成的FeS纳米片结晶性较好,物相单一,没有杂相。在扫速为10 mV/s下,样品的比电容为65.83 F/g。在扫速为10 mV/s下,经过1000次循环之后,FeS纳米片样品的电容保持率在87.20%。
[Abstract]:Due to the worsening of the environment, the intensification of the greenhouse effect and the depletion of fossil fuels, the development of new energy industry is imminent. High performance energy storage and conversion materials are one of the key technologies. Supercapacitors have high power density. Many advantages such as rapid charging and discharging and long cycle life have attracted much attention. In the process of preparing electrode materials it is usually necessary to add binder to enhance the adhesion between electrode materials and collector. However, it will also block the holes of electrode materials and reduce the effective pore area. In order to solve this problem. In this paper, Ni-MOFs and iron sulfide thin film electrodes were prepared by electrochemical and hydrothermal deposition on nickel foams and iron substrates, respectively, without adding any binder. The relationship between the synthesis process parameters and electrochemical properties was studied in order to further optimize the process parameters. Improving the properties of the materials provides a scientific basis. This paper mainly includes the following two aspects of research: 1) foam nickel as a fluid and nickel source, trimethoic acid as ligands. Distilled water and anhydrous ethanol were mixed as solvent and ammonium fluoride as electrolyte. Ni-MOFs film electrode materials were directly grown on nickel foam substrate by electrochemical synthesis method. Different electrochemical synthesis time and current density were studied. The effect of temperature and electrolyte ratio on the preparation of Ni-MOFs foamed nickel film electrode was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Without adding nickel source alone, a layer of needle-like crystal of Ni-MOFs can be grown in the foamed nickel channel. The loading amount increases with the increase of electrochemical time and current density, and the cyclic voltammetry is used. The electrochemical properties of the electrode were measured by constant current charge-discharge method and electrochemical impedance spectroscopy. The results show that the scanning speed is 10 MV / s. The specific capacitance of Ni-MOFs is only 25.63 F / g, and the sweep speed is 10 mV/s. After 500 cycles, the capacitance retention rate is 63.68. In order to improve the specific capacitance of the material, NiOx/C composites were obtained by high temperature treatment with Ni-MOFs as the precursor. The effect of different pyrolysis temperature on the properties of electrode materials was studied. Ni-MOFs electrode was carbonized and converted into Ni/NiOx/C composite electrode material, and the carbonation temperature was 900 鈩，

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