异质纳米结构钴基金属氧化物的设计、制备及其超级电容器性能研究

发布时间：2018-07-01 12:06

本文选题：超级电容器 + 钴基金属氧化物　；参考：《安徽工业大学》2017年硕士论文

【摘要】：超级电容器作为一种新型的能源存储设备,因具有充放电速度快、绿色环保、高能量密度和功率密度而被广泛关注。而电极材料是影响超级电容器性能的关键因素。钴基金属氧化物作为赝电容器电极材料,具有高的理论比容量,制备简单等特点。但是,其电导率低、倍率性能低、循环稳定性差限制了其在电子设备领域的应用。为了研究和改善该类材料的倍率性能和循环稳定性,本文成功制备出了纳米结构的钴基金属氧化物及其复合结构系列的产物。主要研究内容概括如下:采用简单的水热法和化学沉积法制备了具有介孔结构的NiCo_2O_4@MnO_2纳米针阵列,而且材料直接生长在泡沫镍上。该纳米针阵列尺寸均一,长度约为2μm,并且在其表面可观察到MnO_2纳米颗粒。高分辨透射也显示NiCo_2O_4纳米针阵列和MnO_2纳米颗粒成功复合。电化学测试表明,异质结构的NiCo_2O_4@MnO_2(S2)纳米针阵列在1 A·g~(-1)电流密度下比容量可高达2353.4 F·g~(-1)。在8 A·g~(-1)电流密度下,连续循环3000次后,容量保持率仍为92.9%,即使在15A·g~(-1)的大电流密度下循环10000次后,容量仍高达736 F·g~(-1),表现出优异的循环稳定性。采用水热法分别制备出Co_3O_4三维微米球和NiCo_2O_4纳米颗粒,并采用协同组装法将两种物质按照质量比为9:1、4:1、3:1进行复合,制备出不同比例的Co_3O_4/NiCo_2O_4复合材料。Co_3O_4为微米球形,直径约为4μm,并且由纳米颗粒构成,颗粒之间形成间隙。Co_3O_4/NiCo_2O_4复合比例为4:1的样品的电化学性能最为优异。电化学测试表明,Co_3O_4/NiCo_2O_4(4:1)复合物在1 A·g~(-1)电流密度下,放电比容量为1278.1 F·g~(-1),即使在10 A·g~(-1)电流密度下,容量仍为809.4 F·g~(-1)。在8 A·g~(-1)电流密度下,连续循环3000次后,容量保持率为81.6%,表现出优异的电化学性能。通过简单的水热法和化学沉积法在泡沫镍上制备了具有介孔结构的ZnCo_2O_4/NiO纳米片状花结构。二维片层纳米结构具有较大比表面积,缩短了离子、电子的扩散距离。电化学测试表明,ZnCo_2O_4/NiO(M3)样品,在电流密度为1 A·g~(-1)充放电的条件下,其放电比容量高达2797 F·g~(-1),10 A·g~(-1)的放电比容量为2287.2 F·g~(-1),容量保持率为81.8%,即使在40 A·g~(-1)大电流下充放电时,放电比容量高达1079.2 F·g~(-1)。在30 A·g~(-1)下,循环4000次后,容量保持率基本保持在100%,说明ZnCo_2O_4/NiO(M3)复合材料具有优异的电化学循环稳定性。
[Abstract]:As a new type of energy storage devices, supercapacitors have attracted much attention due to their high charge and discharge speed, environmental protection, high energy density and power density. The electrode material is the key factor to affect the performance of supercapacitor. Cobalt-based metal oxide as a pseudo-capacitor electrode material has the advantages of high theoretical specific capacity and simple preparation. However, its low conductivity, low rate performance and poor cyclic stability limit its application in the field of electronic equipment. In order to study and improve the rate performance and cyclic stability of this kind of materials, the products of cobalt based metal oxides and their composite structure series have been successfully prepared in this paper. The main research contents are summarized as follows: NiCo2O4MnO-2 nanoneedle arrays with mesoporous structure have been prepared by simple hydrothermal method and chemical deposition method, and the materials are grown directly on nickel foam. The nano-needle array has a uniform size and a length of about 2 渭 m, and MnO _ 2 nanoparticles can be observed on its surface. High resolution transmission also showed that NiCo2O4 nanoneedle array and MnOST2 nanoparticles were successfully recombined. Electrochemical measurements showed that the specific capacity of the heterostructure NiCoS _ 2O _ 4 @ MnO _ s _ 2 (S _ 2) nanoneedle array could be as high as 2353.4 F ~ (-1) at 1A g ~ (-1) current density. At the current density of 8 A g ~ (-1), the capacity retention rate is 92.9 after 3000 continuous cycles. Even after 10000 cycles at the high current density of 15A g ~ (-1), the capacity is as high as 736F g ~ (-1), showing excellent cyclic stability. Cos / s _ 3O _ 4 microspheres and NiCoS _ 2O _ 4 nanocrystals were prepared by hydrothermal method respectively, and the two substances were compounded by the cooperative assembly method according to the mass ratio of 9: 1: 4: 1: 1. The Co3O4NiCo2O4 composite. Co3O4 / NiCo2O4 composite was prepared in different proportions. The Co3O4NiCo2O4 composite was micrometer spherical. The sample with a diameter of about 4 渭 m and composed of nanocrystalline particles formed a gap between the particles. The electrochemical properties of the samples with a composite ratio of 4:1 NiCo2O4 are the best. Electrochemical measurements showed that the discharge specific capacity of the Co3O / NiCo2O4 (4:1) composite was 1278.1 F g ~ (-1) at the current density of 1A g ~ (-1), and 809.4 F g ~ (-1) even at the current density of 10 A g ~ (-1). At the current density of 8 A g ~ (-1), after 3000 continuous cycles, the capacity retention rate is 81.6, showing excellent electrochemical performance. ZnCo2O4 / nio nanoflakes with mesoporous structure were prepared on nickel foam by simple hydrothermal method and chemical deposition method. The two-dimensional lamellar nanostructures have a large specific surface area, which shortens the diffusion distance of ions and electrons. The electrochemical measurements show that the discharge specific capacity of the sample is up to 2797 F g ~ (-1) and the retention rate is 81.8, even when the current density is 1 A g ~ (-1) charge and discharge. The discharge specific capacity is up to 1079.2 F g ~ (-1) even when charged at 40 A g ~ (-1). At 30 Ag ~ (-1), after 4000 cycles, the capacity retention rate of ZnCoS _ 2O _ 4 / NiO (M3) composite is almost 100, indicating that ZnCoS _ 2O _ 4 / NiO (M _ 3) composite has excellent electrochemical cycling stability.
【学位授予单位】：安徽工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TM53

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