过渡金属硫化物中空纳米结构及其阵列的赝电容特性

发布时间：2018-03-16 00:33

本文选题：超级电容器　切入点：金属硫化物　出处：《华中科技大学》2015年博士论文　论文类型：学位论文

【摘要】：超级电容器相对传统电容具有更高的比能量,相对二次电池具有更突出的比功率,是能量转换与存储系统中化学能与电能转换的候选器件之一,其性能主要取决于高性能电极材料的获得。因此,本研究采用基于柯肯达尔效应的牺牲模板法,制备出具有良好电导率、快速的离子扩散通道且具有丰富氧化还原反应的过渡金属硫化物中空纳米结构及其阵列。设计和可控构造基于过渡金属硫化物中空纳米结构及其复合阵列结构；围绕该材料体系系统地研究了其中空纳米结构形成机制和电荷储能机理；挑选出最优电容性能的中空结构作为正极材料,成功组装了混合型器件,并完成对其性能综合评价。本论文主要研究内容如下：采用基于柯肯达尔效应的牺牲模板法可控制备出硫化钴中空纳米管及其阵列,并对其赝电容特性进行了研究。首先,采用一维棒状Co-盐前驱体作为牺牲模板制备出管径大约250nm、长度大约为3μm为CogS8中空纳米管；其次,通过控制前驱体反应温度制备出不同尺寸的Co9S8中空纳米管。研究表明Co9S8中空纳米管特殊的元素组成和微观结构使其具有优异的电导率、离子扩散通道及电化学活性,因此表现出优于C0304纳米棒的电容性能。随着反应温度的升高纳米管的尺寸之间增大,但是电容性能有下降趋势。在80℃获得的Co9S8中空纳米管具有较高的比表面积和最优的电解质离子扩散通道及电化学活性位点使其具有相对较高的电容性能,在0.5Ag-1下比电容达285Fg-1。在此基础上,获得在FTO和石墨烯纸表面生长的Co9S8中空纳米管阵列,由于特殊的离子扩散通路和电子传导路径使其具有优异的电容性能。设计和可控制备出三元镍钴硫化物中空纳米结构及其阵列,并对其形成机制和电荷存储机理进行了研究。首先,采用海胆状Ni-Co盐前驱体作为牺牲模板法制备出Ni-Co硫化物中空纳米管,并通过控制前驱体反应中Ni/Co元素比例制备出不同结构的Ni-Co硫化物。NiCo2S4纳米管以其特殊的结构和元素组成使得它具有更好的电子传导率和优异的电化学活性,且具有便易的离子扩散通道而表现出比NiCo2S4中空纳米管和NiCo2S4纳米棒更突出的电容性能,在0.5Ag-1下比电容达1145Fg-1,和较高的倍率特性及循环稳定性。Ni/Co (1:2)硫化物表现出相对其他比例更丰富和更活跃的氧化还原反应而表现出良好的电容性能和倍率特性。在此基础上,成功制备出三维NiCo2S4纳米管@Ni-Mn纳米片/石墨烯海绵,在1mA cm-2时其单位面积电容达到1740.3mF cm-2,并表现出优异的倍率特性和循环稳定性。采用一步法制备出由一维针状阵列组成的中空刺猬状Ni-Mn碱式碳酸盐,系统地研究了形成机制,并以此为前驱体成功制备出具有超高性能的Ni-Mn硫化物二级中空结构。首先,通过TEM、SEM、XRD、FT-IR等手段对不同反应温度下的产物进行表征,得出该结构是一种Mn2+诱导生长机理。其次,对该特殊结构前驱体在不同浓度的NaOH、Na2S水溶液中进行水热反应,及不同温度下煅烧以获得不同微观结构的Ni-Mn化合物。由于Ni-Mn硫化物特殊的元素组成而具有较高的电导率和电化学活性而具有相对Ni-Mn氧化物、氢氧化物更突出的性能。最后,通过控制反应中S2-浓度获得Ni-Mn硫化物二级中空结构,并通过对比分析探讨了Ni-Mn硫化物二级中空结构的优异储能机理,由于Ni-Mn硫化物二级中空结构具有突出的电子传导率、离子扩散通道和电化学活活性而表现出优异的性能,在0.5Ag-1时的比电容达到1530.1Fg-1并表现出优异的倍率特性和循环稳定性。开展了不同系列非对称组装工艺研究。将上述较高电容性能的NiCo2S4纳米管作为正极材料与活性炭作为负极材料封装成NiCo2S4//AC混合型器件,该电容器在10～90℃的温度范围内电容性能表现良好,并表现出高的比能量和比功率。同时将相对廉价Ni-Mn硫化物二级中空结构作为正极材料与活性炭负极材料封装成Ni-Mn硫化物//AC非对称器件,能表现出与NiCo2S4//AC混合器件匹敌的比能量和比功率。NiCo2S4@Ni-Mn LDH/石墨烯作为正极材料,VN/石墨烯作为负极材料封装成非对称器件,表现出优异的比能量和比功率。综上所述,本研究结合过渡金属硫化物及其特殊形态结构可控制备技术相关研究,讨论了金属硫化物中空结构及其阵列的形成机制与电化学赝电容电荷存储机理的基础问题,为高性能电极材料与储能器件的开发和应用奠定了良好的技术和理论基础。
[Abstract]:Compared with the traditional capacitance super capacitor has higher specific energy, relative to the two battery is more prominent than power, is one of the candidate chemical and electric power conversion device of energy conversion and storage system, whose performance depends on the high performance electrode material. Therefore, this study adopts kirkendal sacrificial template method based on the effect of preparation, with good conductivity, fast ion diffusion channels with transition metal sulfide hollow nanostructures rich redox reaction and its array. Design and controllable structure based on transition metal sulfide hollow nano composite structure and array structure; the material around the system to study the formation mechanism of nano structure and empty the charge storage mechanism; select the optimal performance of the hollow structure capacitor as cathode material, successfully assembled hybrid devices, and the completion of the The main contents of this paper are as follows:
The sacrificial template method can control the Kirkendall effect based on prepared cobalt sulfide nanotubes and arrays, and the pseudo capacitance characteristics were studied. First of all, as a sacrificial template was prepared using Co- diameter about 250nm one-dimensional rod like salt precursor, the length is about 3 m for CogS8 hollow nanotubes; secondly, by controlling the the reaction temperature of precursor prepared Co9S8 nanotubes with different sizes. The results indicate that the Co9S8 nanotubes special element composition and microstructure which has excellent conductivity, ion channel diffusion and electrochemical activity, the capacitance exhibits a better performance than C0304 nanorods. With increasing reaction temperature increase between the nanotube size, but capacitance there is a downward trend. The performance of Co9S8 hollow nanotubes obtained at 80 DEG C with high specific surface area and optimal electrolyte ion diffusion and electrochemical channel The active site which has relatively high performance capacitors, 285Fg-1. based capacitance in 0.5Ag-1, in FTO and Co9S8 hollow nanotube graphene grown on the surface of the paper, because of the special ion diffusion path and electronic conduction path has the capacitance with excellent performance.
Design and control of prepared three yuan nickel cobalt sulfide hollow nano structure and its array, and the formation mechanism and the charge storage mechanism was studied. Firstly, as a sacrificial template was prepared using Ni-Co sulfide nanotubes urchinlike Ni-Co precursors, and the control of the Ni/Co element precursor prepared by Ni-Co reaction ratio the sulfide.NiCo2S4 nanotubes with different structure with its special structure and elements so that it has better electronic conduction rate and excellent electrochemical activity, and has showed more prominent than the capacitance performance of NiCo2S4 hollow nanotubes and nanorods of NiCo2S4 ion diffusion channels easily, 1145Fg-1 capacitance in 0.5Ag-1,.Ni/Co and rate characteristics the cyclic stability and high sulfide (1:2) showed the proportion relative to other richer and more active redox reaction and showed good electrocatalytic On the basis of these properties, three dimensional NiCo2S4 nanotube @Ni-Mn nanosheets / graphene sponge was successfully prepared. When 1mA cm-2, its capacitance per unit area reached 1740.3mF cm-2, and showed excellent rate and cyclic stability.
By one step prepared one-dimensional array composed of acicular hollow hedgehog Ni-Mn basic carbonate, systematically studied the formation mechanism, and as a precursor prepared with ultra high performance Ni-Mn two grade sulfide hollow structure. First of all, through the TEM, SEM, XRD, FT-IR and other means of product of different reaction temperature the characterization of the structure is a Mn2+ induced growth mechanism. Secondly, the special structure of the precursor at different concentrations of NaOH, hydrothermal reaction of Na2S in aqueous solution, and calcined under different temperatures to obtain Ni-Mn compounds with different microstructure. Because Ni-Mn sulfide special elemental composition and electrochemical conductivity with high activity and relatively Ni-Mn oxides, hydroxides performance more prominent. Finally, by controlling the concentration of S2- was two Ni-Mn sulfide hollow structure reaction, and through comparative analysis Discusses the excellent storage Ni-Mn two grade sulfide hollow structure can mechanism, because the Ni-Mn two level of sulfide hollow structure with electronic conduction outstanding rate, ion diffusion and electrochemical activity of channel and show excellent performance in 0.5Ag-1, the specific capacitance of 1530.1Fg-1 and exhibited excellent rate performance and cycle stability.
The different series of asymmetric assembly technology research. The high capacitance performance of NiCo2S4 nanotubes as cathode material and activated carbon as anode material is packaged into a NiCo2S4//AC hybrid device, the performance of the capacitor in the temperature range of 10~90 DEG C in good performance, and exhibits high specific energy and power. At the same time will be relatively cheap two Ni-Mn sulfide hollow structure as packaging cathode material and activated carbon anode materials into Ni-Mn sulfide //AC asymmetric device can show mixed with the NiCo2S4//AC device to match the specific energy and power.NiCo2S4@ Ni-Mn LDH/ graphene as anode material, VN/ graphene as anode materials encapsulated into asymmetric device exhibits excellent specific energy and the specific power.
In summary, this study combined with transition metal sulfide and its special morphology controlled preparation technology research, discusses the basic problems of metal sulfide hollow structure and array formation mechanism and electrochemical pseudocapacitor charge storage mechanism, and laid a good technical and theoretical basis for the development and application of high performance materials and storage electrode devices.

【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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