过渡金属化合物纳米材料的化学合成及其储能性能研究

发布时间：2018-05-11 17:58

本文选题：过渡金属化合物 + 纳米结构　；参考：《西北大学》2015年硕士论文

【摘要】：当今世界的能源越来越紧缺,环境污染也越来越严重,而发展新型能源材料是解决能源危机和环境污染的一条有效途径。其中过渡金属化合物因为具有特殊的的外层价电子,而产生了奇特的物理和化学性质,所以其在催化、电化学、传感、磁性以及吸附等领域都有着广泛应用。最近将具有新颖形貌的过渡金属化合物纳米结构,如氢氧化物、氧化物、碳化物和硫化物等,应用于电化学储能方面的研究受到了大家的广泛关注。本论文主要采用简单的水热反应和高温煅烧的方法制备了形貌和结构可调的过渡金属化合物纳米材料(Ni(OH)2纳米片、CoO纳米线、Mo2C纳米线等)。将以上这些纳米结构材料用作超级电容器电极或锂离子电池的阳极材料,均表现出了良好的电化学储能效果。本文研究的具体内容主要包括以下三个部分：1：通过简单的水热方法及后续的二次水热或煅烧分别得到了由分层多孔Ni(OH)2纳米片组装的Ni/Ni(OH)2杂化结构和NiO纳米链。在整个实验过程中,控制还原剂N2H4·H2O的加入量是控制前躯体Ni纳米链形貌的关键,也就控制了随后的Ni/Ni(OH)2杂化结构和NiO纳米链的形貌。然后,通过XRD、SEM、FETEM、TEM、BET和FTIR等测试手段分析了Ni/Ni(OH)2杂化结构和NiO纳米链的结构和形貌。所合成的Ni/Ni(OH)2杂化结构和NiO纳米链用作超级电容器的电极,可表现出优异的电化学性能。其中Ni/Ni(OH)2杂化电极在电流密度为2Ag-1下可获得高达3247 F g-1的比容量；NiO纳米链电极在电流密度为1Ag1时的比容量可以达到413Fg-1。目前这种合成方法具有简单、高效和环境友好等优点。2：采用简单的水热法合成了Co(CO3)0.5(OH)·0.11H2,通过调节实验的pH可获得不同形貌的Co(CO3)0.5(OH)·0.11H2O。我们将尺寸较小的Co(CO3)0.5(OH)·0.11H2O前躯体分别在管式炉和马弗炉中高温煅烧得到了CoO纳米线和Co304纳米线。将CoO纳米线和Co3O4纳米线作为锂离子电池的阳极材料,均取得了一定储锂效果。在0.1 C的电流密度下,CoO纳米线和C0304纳米线的首圈比容量分别为850 mAh g-1和1027 mAh g-1。3：利用简单水热法制备得到了MoO3-EDA,通过调节水热温度,可以得到不同形貌的MoO3-ED A。将前躯体MoO3-EDA纳米线在通有H2-Ar混合气的管式炉中煅烧可得到Mo2C纳米线；将不同形貌的前躯体MoO3-EDA与不同的硫源分别进行水热反应,可获得不同形貌的MOS2。我们通过XRD、SEM、TEM、BET和FTIR等表征手段分析了前躯体MoO3-EDA、Mo2C纳米线以及MoS2纳米线和颗粒的结构和形貌。分析对比后,分别将Mo2C纳米线和MoS2纳米线用作锂离子电池的阳极材料,其首圈比容量分别为1037mAhg-1和743mAhg-1。
[Abstract]:Nowadays, energy is becoming more and more scarce and environmental pollution is becoming more and more serious in the world, and the development of new energy materials is an effective way to solve the energy crisis and environmental pollution. Transition metal compounds have been widely used in the fields of catalysis, electrochemistry, sensing, magnetism and adsorption because of their unique physical and chemical properties due to their special outer valence electrons. Recently, nanostructures of transition metal compounds with novel morphologies, such as hydroxides, carbides and sulphides, have attracted much attention in electrochemical energy storage. In this paper, a simple hydrothermal reaction and high temperature calcination method were used to prepare transition metal compound nanomaterials, such as NiOH2 nanowires and Mo2C nanowires, which have adjustable morphology and structure. These nanostructured materials were used as anode materials for supercapacitor electrodes or lithium ion batteries, and showed good electrochemical energy storage effect. The main contents of this paper are as follows: 1: through simple hydrothermal method and subsequent secondary hydrothermal or calcination, the Ni/Ni(OH)2 hybrid structure and NiO nanowires assembled by layered porous Ni(OH)2 nanoparticles are obtained respectively. In the whole experiment, controlling the amount of reducing agent N2H4 H2O is the key to controlling the morphology of the precursor Ni nanochain, which controls the subsequent Ni/Ni(OH)2 hybrid structure and the morphology of the NiO nanochain. Then, the structure and morphology of Ni/Ni(OH)2 hybrid structure and NiO nanochain were analyzed by means of XRDX SEMX FETEM Tem BET and FTIR. The synthesized Ni/Ni(OH)2 hybrid structure and NiO nanochains can be used as electrodes for supercapacitors and exhibit excellent electrochemical performance. The specific capacity of Ni/Ni(OH)2 hybrid electrode can reach 413Fg-1 when the current density is 1Ag1, and the specific capacity of nio nanochain electrode is up to 3247 F g ~ (-1) when the current density is 2Ag-1. At present, this method has the advantages of simplicity, high efficiency and environmental friendliness. Coco _ (3) O _ (0.5) O _ (2) 0.11H _ (2) has been synthesized by a simple hydrothermal method. By adjusting the pH of the experiment, different morphologies of Coco _ (3) O _ (3) O _ (0.5) O _ (H) 0.11H _ 2O can be obtained. The CoO nanowires and Co304 nanowires were obtained by calcining the smaller COCO3 (0.5) OH) 0.11H2O precursors in a tube furnace and a muffle furnace at high temperatures, respectively. Both CoO nanowires and Co3O4 nanowires were used as anode materials for lithium ion batteries. The first cycle specific capacities of CoO nanowires and C0304 nanowires were 850 mAh g-1 and 1027 mAh g-1.3 at current density of 0.1C, respectively. Moo _ 3-EDAs were prepared by a simple hydrothermal method. Different morphologies of MoO3-ED A were obtained by adjusting the hydrothermal temperature. The Mo2C nanowires can be obtained by calcining the precursor MoO3-EDA nanowires in a tubular furnace with H2-Ar mixture, and MOS2 with different morphologies can be obtained by hydrothermal reaction of the precursor MoO3-EDA with different sulfur sources. The structure and morphology of the precursor MoO3-EDA-Mo2C nanowires and MoS2 nanowires and particles were characterized by XRDD-SEMMO-TEMT-BET and FTIR. After analysis and comparison, Mo2C nanowires and MoS2 nanowires were used as anode materials for lithium-ion batteries, and the first cycle specific capacities were 1037mAhg-1 and 743mAhg-1, respectively.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

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