低温燃烧合成纳米钒基材料及性能研究

发布时间：2018-06-21 01:04

本文选题：低温燃烧合成 + 钒基材料　；参考：《北京科技大学》2017年博士论文

【摘要】：纳米钒基材料在光、电、热、磁等方面具有独特的性能,广泛的应用于能源、催化、合会等领域。低温燃烧合成是近年来发展迅速的一种制备纳米材料的新的湿化学方法,具有简便、快捷、能耗和成本低、产物活性高等诸多优点。本论文将低温燃烧合成方法应用于纳米钒基材料的制备。主要研究内容包括以下几个方面：(1)研究了燃料、氧化剂等原料以及燃烧气氛、点燃条件等参数对钒氧化物粉末制备及产物性能的影响,成功通过一步燃烧法合成了单相的二氧化钒、三氧化二钒、五氧化二钒。以柠檬酸和甘氨酸为混合燃料,摩尔比为4时,可制备得到粒径约为15～20nm,比表面积为18.5 m2·g-1的VO2粉末,产物具有MST转变特性；通过控制燃烧气氛,使燃烧反应在氮气气氛下进行,可制备得到粒径约为40～80 nm的颗粒组成的纳米V203;尿素为燃料时,可制备出直径约为4～6μm的V2O5片状单晶。该V205单晶薄片呈现出优异的锂电特性,作为锂电正极材料时,在0.1 A·g-1的电流密度下,50次循环后,容量为234mAh·g-1。(2)通过在溶液中引入水溶性葡萄糖碳源,首次利用低温燃烧合成法一步制备氧化钒/碳复合材料。研究了葡萄糖添加量对氧化钒/碳产物的物相、形貌的影响,在葡萄糖与偏钒酸铵的摩尔比为0.2,可制备得到二维多孔片状结构的VOx/0.2C样品,其中无定形的具有混合价态的VOx颗粒均匀分布在碳片上。研究了该氧化钒/碳粉末作为锂离子电池负极材料时的电化学性能,在0.1 A·g-1电流密度下,100次循环后该负极材料的可逆容量为1088 mAh·g-1,在1 A·g-4电流密度下,在400次循环后可逆容量稳定在776 mAh·g-1。(3)将低温燃烧合成各种价态的氧化钒前驱物进行氨气还原氮化制备氮化钒,研究了前驱物的价态、粒度、形貌等对氮化反应以及产物的影响,发现不同价态的氧化钒前驱物在氮化反应过程中的相变以及氮化产物的形貌、粒度均不同,所制备氮化钒的电化学性能也不同。以V02作为前驱物制备VN,随着反应温度的升高,V02首先转变为V5O9(400℃),再转变为V203(500℃)、VO0.9(600℃),直到温度升高至700℃实现完全氮化,得到由30～40 nm的纳米颗粒组成的VN产物；以V205作为前驱物制备VN,V2O5首先转变为VO2(300℃),随着氮化温度的升高,逐步转变为VO2和VO的混合物(400℃、500℃)、再转变为VO0.9(600℃),700℃氮化完全,得到由30～40 nm的纳米颗粒组成的片状VN。将所制备VN作为超级电容器的电极材料应用时,在0.1 A·g-4电流密度下,比容量为83 F·g-1。(4)将低温燃烧合成的氧化钒/碳复合前驱物进行氨气还原氮化制备出氮化钒/碳复合材料。研究了葡萄糖添加量以及氨气还原氮化常数对所制备氮化钒/碳粉末性能等的影响,优化出最佳的反应参数,制备出电化学性能优异的氮化钒/碳复合粉木。在葡萄糖与偏钒酸铵的摩尔比为1,氮化反应温度为600℃,制备得到二维多孔片状结构,比表面积为21.1 m2·g-1,颗粒粒径约为7～10nm的VN/1C-600样品,作为锂离子电池的负极材料时,在1 A·g-1电流密度下,500次循环后可逆容量稳定在650 mAh·g-1,0.1 A·g-1电流密度下,100次循环后可逆容量为712 mAh·g-1。当氮化温度升至700℃时,可得到比表面积为29.2 m2·g-1,VN颗粒粒径约为9-13 nm的VN/1C-700样品,作为超级电容器的电极材料应用时,在75：15：10(活性物质：导电剂：粘结剂)质量配比下,电流密度为0.1、0.25、0.5、1、2和5 A·g-1时,电压窗口为-1～0V时,VN/1C-700样品,对应的比容量分别为196、139、123、110、102和78F·g-1。
[Abstract]:Nano vanadium based materials in light, electricity, heat, magnetic fields have unique properties, widely used in energy, catalysis, cooperation and other fields. The low temperature combustion synthesis is developed rapidly in recent years for the preparation of nanomaterials new wet chemical method is simple, fast, low energy consumption and cost. The activity of product advantages. This paper will be of low temperature Combustion synthesis method applied to nano vanadium base material was prepared. The main contents include the following aspects: (1) of fuel, raw materials such as oxidation agent and combustion atmosphere, the influencing conditions of vanadium oxide powder preparation and properties of the product, through the success of one step combustion synthesis of two vanadium oxide phase the three oxidation two V, five of two vanadium. With citric acid and glycine as fuel, molar ratio of 4, can be prepared by the particle size is about 15 ~ 20nm, than VO2 powder surface area is 18.5 M2 - g-1, the product has the transition properties of MST; through the atmosphere to control the combustion, the combustion reaction under nitrogen atmosphere that can be prepared by particle size of about 40~80 nm particle group The nano V203; urea as fuel, can be prepared by V2O5 flake crystal diameter is about 4~6 m. The V205 single crystal shows excellent characteristics of the lithium sheet, as cathode materials, the current density of 0.1 A - g-1, after 50 cycles, the capacity is 234mAh - g-1. (2) in the solution by introducing a water soluble carbon source, used for the first time One step synthesis method for preparing vanadium oxide / carbon composite materials. Low temperature combustion of glucose addition on vanadium oxide / carbon phase, morphology, the molar ratio of glucose and ammonium metavanadate was 0.2, can be prepared by two dimensional porous sheet structure of VOx/0.2C samples, including amorphous VOx particles with mixed valence distribution In the carbon film. The vanadium oxide / carbon powder electrochemical performance as anode materials for lithium ion batteries, at 0.1 A g-1 current density, after 100 cycles the reversible capacity of the cathode material is 1088 mAh - g-1, at 1 A G-4 current density, after 400 cycles the reversible the capacity is stable at 776 mAh g-1. (3) will be all kinds of low temperature combustion synthesis Vanadium oxide precursor for preparing valence vanadium nitride nitride for ammonia reduction, valence, precursor on the particle size and morphology of nitridation reaction and the product of the effect, found that phase transition vanadium oxide precursors with different valences in the nitridation process and morphology of the nitride product, the size are different. Electrochemical preparation of vanadium nitride It is also different. The preparation of VN with V02 as the precursor, with the rise of reaction temperature, V02 first into V5O9 (400 C), and then transformed into V203 (500 C), VO0.9 (600 DEG C), until the temperature rises to 700 degrees to achieve complete nitridation, VN products are composed of nano particles of 30~40 nm the preparation of VN; using V205 as precursor, V2O5 first converted to VO2 (300 C), with the increase of nitriding temperature, gradually transformed into a mixture of VO2 and VO (400 DEG, 500 DEG C), and then transformed into VO0.9 (600 C), 700 nitridation completely, flake VN. composed of nano particles of 30~40 nm in the preparation of VN as the application of super capacitor electrode material in 0.1, A G-4 current density, specific capacity of 83 F g-1. (4) will The synthesis of vanadium oxide / carbon composite precursor ammonia prepared vanadium nitride / carbon composite materials for low temperature combustion. Reduction and nitridation of glucose and ammonia reduction and nitridation effect on constant prepared vanadium nitride / carbon powder performance, optimize the optimal reaction parameters, preparation of vanadium nitride / excellent the electrochemical properties of carbon composite Wood powder. The molar ratio of glucose and ammonium metavanadate was 1, reaction temperature is 600 DEG C, the prepared porous two-dimensional sheet structure, specific surface area is 21.1 M2 - g-1, the particle size is about VN/1C-600 samples of 7 ~ 10nm as anode materials for lithium ion batteries, in 1 A. G-1 current density after 500 cycles, the reversible capacity is stable at 650 mAh G-1,0.1 A, the current density of g-1, after 100 cycles, the reversible capacity was 712 mAh g-1. when the nitridation temperature rose to 700 degrees, can obtain the specific surface area is 29.2 M2 - g-1, VN particle size is about 9-13 nm VN/1C-700 samples, used as supercapacitor electrode materials, in 75:15: 10 (active substances: conductive agent: binder) with quality Than under the current density of 0.1,0.25,0.5,1,2 and 5 A g-1, the voltage window is -1 ~ 0V, VN/1C-700 sample, the corresponding capacity ratio were 196139123110102 and 78F - g-1.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TQ135.11;TB383.1

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