多形貌锐钛矿型介孔二氧化钛的研究

发布时间：2018-06-27 22:32

  本文选题：锐钛矿 + 介孔　； 参考：《天津大学》2015年博士论文

【摘要】：随着不可再生能源的枯竭和环境问题的恶化,开发利用清洁可再生能源迫在眉睫。染料敏化太阳能电池有效的将太阳能转化成电能。锂离子二次电池有效的储存电能。介孔TiO_2具有孔体积大、孔径可调、比表面积高、成本低廉、结构稳定、环境友好和电子和光学性质优异等优点,用作染料敏化太阳能电池光阳极材料,增加染料的化学吸附量,提高太阳能转化效率;用作锂离子电池负极材料,增加电极与电解质的接触面积、缩短锂离子的扩散路径,而提高储能能力。本文旨在优化和开创介孔TiO_2的制备方法、制备新形貌介孔TiO_2、研究介孔TiO_2的形成机制及探索介孔TiO_2在锂离子二次电池和染料敏化太阳电池中的应用。本文,以十六烷基胺为结构导向剂,通过溶胶-凝胶和溶剂热两步法及空气下高温锻烧,制备出单分散亚微米锐钛矿型介孔球形TiO_2。系统探索了反应温度和陈化时间,优化了制备方法;介孔球形TiO_2用作锂离子电池负极材料,1 C(1C=170 mA g-1)下,200次循环后放电比容量仍有146.4 mA h g-1,容量保持率为85.1%;用作染料敏化太阳能电池光阳极,获得η=6.25%的光电转化效率。通过对以十六烷基胺为结构导向剂、溶胶-凝胶和溶剂热两步法制得的TiO_2,在氩气中高温将有机物原位碳化后,制备出单分散亚微米锐钛矿型介孔球形TiO_2/C。采用多种测试手段表明构成介孔球形TiO_2/C的基本颗粒表面包覆了一层约1.5 nm厚的碳膜,碳含量为1.1 wt%。用作锂离子电池负极材料,1 C和10C下,介孔球形TiO_2/C的放电比容量分别为~180 mA h g-1和110 mA h g-1;而介孔球形TiO_2的放电比容量仅分别为~170 mA h g-1和~97 mA h g-1。开创了一步溶剂热法,以十六烷基胺为结构导向剂,快速、有效的制备单分散锐钛矿型介孔球形Ti O_2。用作锂离子电池负极材料,1 C循环50次后,单分散介孔球形TiO_2仍有约150 mA h g-1的比容量,高于商品化25 nm TiO_2纳米粒子110 mA h g-1的比容量。将方法扩展至制备球/片结构Li_4Ti_5O_(12),20 C(1 C=175 mA g-1)循环500次,比容量仍在100 mA h g-1以上。不加添加剂的情况下,甲醇和钛酸丁酯在常温、常压下反应得到的中间体TBM作为原位模板在空气中水解后,通过“原位转化机理”制备出厚度为13-30nm的单颗粒层锐钛矿型介孔片状TiO_2。用作锂离子电池负极材料,在5 C下,经过4000次的充放电后,片状介孔TiO_2仍有~60%的容量保持率。使用溶剂热方法,在甲醇-钛酸丁酯体系条件中,首次制备出了新形貌三维锐钛矿型介孔梭形介晶TiO_2,并提出了一种方向附着生长机理。用作锂离子电池负极材料,1 C下,1000次的循环中,其可逆比容量保持在110 mA h g-1。
[Abstract]:With the depletion of non-renewable energy and the deterioration of environmental problems, it is urgent to develop and utilize clean and renewable energy. Dye-sensitized solar cells effectively convert solar energy into electricity. Lithium ion secondary battery can store electric energy effectively. Mesoporous TiO2 has the advantages of large pore volume, adjustable pore size, high specific surface area, low cost, stable structure, environment-friendly and excellent electronic and optical properties. It is used as photoanode material for dye-sensitized solar cells to increase the amount of chemisorption of dyes. It can be used as anode material of lithium ion battery, increase the contact area between electrode and electrolyte, shorten the diffusion path of lithium ion, and improve the energy storage ability. The purpose of this paper is to optimize and create the preparation method of mesoporous TiOs _ 2, to prepare new mesoporous TiO-2, to study the formation mechanism of mesoporous TiO-2 and to explore the application of mesoporous TiO-1 in lithium ion secondary battery and dye sensitized solar cell. In this paper, using hexadecylamine as the structure guide, the monodisperse submicron mesoporous spherical TIO _ 2 was prepared by sol-gel and solvothermal two-step method and high temperature calcination in air. The reaction temperature and aging time were systematically explored and the preparation method was optimized. Mesoporous spherical TiO2 was used as anode material for lithium ion batteries. After 200 cycles, the specific discharge capacity was still 146.4 Ma 路g ~ (-1), and the capacity retention was 85.1%. As a dye sensitized photoanode for solar cells, the photoconversion efficiency of 畏 ~ (6.25%) was obtained. By using hexadecylamine as structure guide, sol-gel and sol-thermal two-step synthesis of TIO _ 2s, the monodisperse submicron mesoporous TIO _ 2 / C was prepared by in-situ carbonization of organic matter at high temperature in argon. The surface of the basic particles of mesoporous tio _ 2 / C is coated with a carbon film about 1.5 nm thick, and the carbon content is 1.1 wt. The discharge specific capacities of mesoporous TiO-2 / C and mesoporous spherical TiO-2 are 180mA hg-1 and 110mA hg-1, respectively, while mesoporous spherical TiO-2 discharge capacity is only 170mA hg-1 and 97mA hg-1, respectively, at 10C and 10C for lithium-ion batteries. A one-step solvothermal method was developed to prepare monodisperse anatase spherical mesoporous TIO _ (2) with hexadecylamine as structure guide. After 50 cycles as anode material for lithium ion battery, the specific capacity of monodisperse mesoporous TiO-2 is still about 150mAhg-1, which is higher than that of commercial 25nm TiO-2 nanoparticles (110mAhg-1). The method was extended to the preparation of Li4Ti5O12 / 20C (1CN175mAg-1) cycle with a specific capacity of more than 100mA / g ~ (-1). The intermediate TBM obtained by reaction of methanol with butyl titanate at room temperature and atmospheric pressure was hydrolyzed in air as an in-situ template without additive. In situ conversion mechanism was used to prepare single granular layer anatase mesoporous tio _ s _ 2s with thickness of 13-30nm. When used as anode material for lithium ion batteries, after 4000 charges and discharges at 5 C, the volume retention of TiO-2 in sheet mesoporous cells is still 60%. A new 3D anatase mesoporous TiO-2 was prepared by solvothermal method in methanol-butyl titanate system for the first time, and a directional adhesion growth mechanism was proposed. The reversible specific capacity of the cathode material for lithium ion battery kept at 110mA h g -1 in 1000 cycles at 1C.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TQ134.11
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本文编号：2075493