镍基复合物材料的制备及其在超级电容器上的应用研究

发布时间：2018-01-10 05:02

本文关键词：镍基复合物材料的制备及其在超级电容器上的应用研究　出处：《吉林大学》2017年博士论文　论文类型：学位论文

【摘要】：镍基硫化物,氧化物和氢氧化物为常见的过渡金属化合物,具有很高的电化学活性。在储能方面,镍基化合物作为电活性物质在电极表面及其近表面进行快速的氧化还原反应可以产生赝电容,是很好的法拉第赝电容器电极材料。赝电容器的能量存储效率要远远大于双电层电容器,这对于填补电池和传统电容器之间的能量空白是非常重要的。但是,单纯的氧化镍、氢氧化镍和硫化镍等镍基化合物无论是在材料的形貌、结构,还是导电性以及电化学性能方面都很难达到令人满意的程度,其较宽的禁带宽度严重限制了电子载流子的数量及利用效率。而以这些镍基化合物为基质组合而成的复合材料则可以利用各元材料的本征特征形成优势互补,从而达到克服上述缺点的目的。另外,各元材料在参与电化学反应的过程中往往伴随着协同作用的发生,这无论是对于器件的能量存储还是转化都有着很大的促进作用。本论文主要针对镍基复合材料的合成及其在超级电容器电极材料方面的应用进行了研究,通过优化实验方案避免材料团聚,调控材料形貌和孔隙率,改善材料的导电性以合成均匀分散的纳米/微米尺寸电极材料,从而获得大的比电容及倍率性能、长的使用寿命和高的功率密度。研究工作主要集中在以下几个方面:1.采用改进界面法及后续的硫化工作制备了镍-锌二元体系化合物材料(Ni1-x Znx OH和NixZn1-x S),探寻避免纳米材料团聚的方法,并对所制得的材料进行了物相、形貌和电化学性能表征。在这里,我们使用低密度,与水互溶性良好的DMF(二甲基甲酰胺)溶剂取代了传统界面方法中所使用的非水溶性有机溶剂,如CCl4和CH2Cl2等。通过这样的改进之后,原本应用范围狭小的界面法将具备更加广泛的用途。在用该方法合成了由Ni1-xZnx OH超薄片组成的三维层状结构材料后,通过进一步的水热处理,我们获得了NixZn1-x S多孔纳米球样品,由于受到柯肯特尔效应(Kirkendall)的作用,在30 nm超小直径的NixZn1-x S纳米颗粒内部形成了丰富的相互连接的纳米孔。这样的结构不仅增大了材料的比表面积(148.4 m2 g-1),而且为离子扩散提供了快速传输的通道,有利于获得高的的比电容和良好的循环稳定性。2.采用一步水热的方法在泡沫镍上原位生长了多层Ni1-xZnx S复合物。利用Zn元素掺杂的技术,控制Zn元素在复合物各层中含量的变化来控制形貌的变化。具备不同形貌的多层结构可以提供大范围的孔径尺寸分布,为电解液离子的快速进出提供通道并缩短离子迁移程。另外各层之间均是通过原位生长的方法构造的,这对于减小电子在层与层之间的传输阻力非常有效,因此其能够提供良好的电化学性能。通过该种构造方式得到的的多层结构材料不仅能够获得高的比电容性能和良好的循环稳定性,而且对于获得超大倍率性能来说也是非常有效的。3.通过硫化和随后的水解反应,我们成功合成了一种高质量负载(8.33 mg cm-2)的新型Ni foam-Ni3S2@Ni(OH)2-graphene三明治结构电极(NF-NN-G)。该样品中Ni3S2和Ni(OH)2的电导率同时得到了提高。其中位于上层的Ni(OH)2表面覆盖着一层薄的石墨烯膜,位于下层的Ni3S2通过在泡沫镍上原位硫化而成,主要作为连接Ni(OH)2和泡沫镍的桥梁。石墨烯不仅增加了Ni(OH)2的结构稳定性并且有效地提高了其电化学性能。由于高活性材料负载量的电极的导电性会随着负载的厚度增加而急剧减小,这种设计对于提高大负载量电极的导电性非常有效,能够减小电子在传输过程中的损失,提高材料的利用率,进而获得高的电化学性能。4.通过简单的一步水热法成功制备了多级三维层状Zn S/Zn O/Ni9S8/Ni(OH)2复合材料。使用Zn S作为类催化剂材料可持续生产辅助支撑材料Zn O以充分利用电极的内部空间,Ni9S8和Ni(OH)2则作为主要活性材料参与电化学反应。Zn S在水解成为Zn O后,其副产物H2S可以与溶液中过量的Zn2+反应生成新的Zn S,这一机制可以保证三维结构在空间范围内理论上无限扩展,为电极材料提供丰富的电活性位点。此外,使用该策略获得的电极材料中,Ni9S8/Ni(OH)2良好的电化学活性与辅助材料的结构稳定性之间具有良好的协同效应,因此可以保证其在获得优异的电化学性能的同时也能够具备极其优秀的循环性能。
[Abstract]:Nickel sulphide, oxides and hydroxides as transition metal compounds are common, with high electrochemical activity. In terms of storage, nickel based compound as an active substance on the electrode surface and near surface rapid oxidation can produce pseudocapacitive redox reaction, is a very good Faraday PSEUDOCAPACITORS electrode materials for energy storage efficiency. PSEUDOCAPACITORS is much larger than the electric double layer capacitor, which is very important for filling between the battery and the traditional capacitor energy gap. However, pure nickel oxide, nickel hydroxide and nickel sulfide, nickel based compound materials in both the structure, morphology, and electrical conductivity and electrochemical properties are difficult satisfactory, the broad band gap has seriously restricted the number of electron carriers and utilization efficiency. With these compounds as the matrix formed by the combination of complex The material can form complementary advantages using the intrinsic characteristics of each material, so as to achieve the purpose of overcoming the defects. In addition, each element in the material processes involved in the electrochemical reaction is often accompanied by a synergistic effect, whether it is for the energy storage device or transformation has great role in promoting this paper. Mainly for nickel base composite material and its application in the synthesis of super capacitor electrode materials were studied through optimization experiment materials to avoid agglomeration, regulation of material morphology and porosity, conductive materials to improve the synthesis of uniform dispersion of nano / micron size electrode material, so as to obtain the specificcapacitance and rate capability of large, long the service life and high power density. The research work mainly focuses on the following aspects: 1. using Ni Zn two by improved interface method and subsequent curing work Element system of compound material (Ni1-x Znx OH and NixZn1-x S), to explore the way to avoid the agglomeration of nano materials, and the prepared materials for the phase, morphology and electrochemical performance characterization. Here, we use low density, and good water solubility DMF (two methyl formamide) solvent instead of the use of traditional interface method in non water soluble organic solvent, such as CCl4 and CH2Cl2. After the improvement, the narrow scope of the original application interface method will have more extensive use. In the three-dimensional layered materials composed of Ni1-xZnx OH thin films were synthesized by this method, through the hydrothermal treatment further, we obtained the NixZn1-x S porous nanospheres were due to Kirkendall effect (Kirkendall) role in the 30 nm ultra small diameter internal NixZn1-x S nanoparticles formed abundant interconnected nanopores such. The structure not only increases the surface area of the material (148.4 M2 g-1), and provide a fast transmission channel for ion diffusion, is beneficial to obtain high specific capacitance and good cycle stability of.2. by one-step hydrothermal in situ grown on nickel foam multilayer Ni1-xZnx S composites. By Zn doping the change of control technology, the content of Zn in each layer in the compound to control the morphology. The pore size has a multilayer structure with different morphologies can provide a wide range of distribution, to provide a channel for the rapid import of electrolyte ions and shorten the ion transfer process. In addition between the layers are constructed by in situ growth. This is very effective in the electronic transmission to reduce the resistance between layers, so it can provide a good electrochemical performance. The structures of multilayer structure materials not only can be obtained High specific capacitance and good cycle stability performance, and to get large rate performance is also very effective.3. through vulcanization and subsequent hydrolysis reaction, we successfully synthesized a kind of high quality load (8.33 mg cm-2) of the new Ni foam-Ni3S2@Ni (OH) 2-graphene sandwich electrode structure (NF-NN-G) and Ni Ni3S2. In the sample (OH) 2 and the conductivity is improved. The upper Ni (OH) 2 is covered with a thin layer of graphene film, and in the lower layer by Ni3S2 on nickel foam in situ vulcanization, as main connection Ni (OH) 2 and the bridge of nickel foam graphite. Not only was increased by Ni (OH) 2 of the structural stability and effectively enhance the electrochemical performance. The conductive electrode active material of high load increases with the increase in the thickness of the load decreases sharply, this to improve the design of large load electrode Very effective conductivity, can reduce the loss of electrons in the transmission process, improve the utilization rate of materials, and the electrochemical performance of.4. high by simple one step hydrothermal method preparation of multi-level three-dimensional layered Zn (OH) S/Zn O/Ni9S8/Ni 2 composite material. Using Zn S as catalyst materials for sustainable production the auxiliary support material Zn O in order to make full use of the internal electrode space, Ni9S8 and Ni (OH) 2 as the main active material in electrochemical reactions of.Zn S in Zn O after hydrolysis as its by-product, H2S and excess Zn2+ in the reaction solution to generate a new Zn S, this mechanism can ensure the three-dimensional structure of unlimited expansion in the range of space theory, provide electricity rich active sites as the electrode material. In addition, the use of the strategy to obtain the electrode material, Ni9S8/Ni (OH) between the structure of 2 good electrochemical activity and stability with auxiliary materials With good synergy, it can guarantee excellent electrochemical performance and excellent cycle performance.

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB33;TM53

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