基于天然纤维素物质的光电转化和锂离子电池材料的制备和性质研究

发布时间：2018-02-04 12:47

本文关键词： 纤维素表面溶胶-凝胶法自组装光电转化锂离子电池　出处：《浙江大学》2017年博士论文　论文类型：学位论文

【摘要】：进入二十一世纪,工业的飞速发展伴随着巨大的能源消耗,人类面临着化石燃料等不可再生能源的日益枯竭,以及随之而来的一系列严峻的环境问题。因此,开发新型清洁能源材料和充分利用太阳能等可再生能源迫在眉睫。自然界中存在着大量的生物质资源,其中,天然纤维素物质具有丰富的产量、良好的生物可降解性、生物相容性、柔韧性和机械强度,并且纤维素分子之间复杂的相互作用赋予其独特的三维多层级结构、多孔性和大比表面积。因此,天然纤维素物质是优良的生物模板,其表面丰富的活性羟基使多种客体材料在纤维素表面的自组装成为可能。本文是基于天然纤维素物质(无灰定量滤纸)为模板,在纤维素单根纳米纤维表面进行多种氧化物客体分子的自组装,随后以不同的方式进行后处理,制备得到结合了天然纤维素模板独特结构和客体材料特异性功能的新型先进功能纳米材料,可用于光电转化体系和锂离子电池等领域的研究,主要内容如下:1、光系统Ⅱ/多孔二氧化钬纳米管网络光阳极体系:基于天然纤维素的表面羟基和钛醇盐的共价作用,在滤纸的纳米纤维表面进行二氧化钛凝胶薄膜的层层自组装,在空气中煅烧除掉纤维素模板,得到精确复制了模板多层级多孔网络结构的锐钛矿型二氧化钬纳米管材料。用该二氧化钬材料对电极基底表面进行修饰。随后,将从菠菜叶片中提纯出的具有光解水功能的光系统Ⅱ(PSⅡ)蛋白组装在电极上,成功构建了新型蛋白/半导体复合仿生光阳极体系。由于电极的平面结构被二氧化钛纳米管材料优化,蛋白在电极表面的负载量得以提高。此外,PSⅡ蛋白和二氧化钛之间具有协同作用,在PSⅡ蛋白和二氧化钛能级间的电子传递模拟了自然界光合作用中的电子传递"Z"型链。该复合光阳极体系具有良好的光电化学性能。将其用于太阳能的转化和电能的产生,在模拟太阳光的白光照射下能产生较高的光电流,在一定外加条件下能够驱动LED灯泡发光。2、光系统Ⅱ/纳米管状氧化铟锡薄膜共组装光阳极体系:基于天然纤维素的表面羟基和铟醇盐、锡醇盐的共价作用制备得到氧化铟锡(ITO)凝胶薄膜/纤维素复合材料,在空气中煅烧除掉纤维素成分,即可得到精确复制了纤维素模板的多层级多孔网络结构的纳米管状ITO薄膜材料。该材料对可见光透过性良好,其铟锡比使材料具有较高的导电率。将纳米管状ITO薄膜材料用导电金胶粘附在电极基底上实现对平面电极的修饰,并将PSⅡ蛋白组装在ITO薄膜材料的多孔网络结构中,构建得到一个新型半人工PSⅡ/纳米管状ITO薄膜复合光阳极体系。纳米管状ITO薄膜材料在电极表面的修饰有效提高了 PSⅡ蛋白的负载量;ITO材料的纳米管结构及其优越的光学和电学性能有效增强了电子在光阳极体系中的传递效率。将该复合光阳极体系用于太阳能的转化和电能的产生,在模拟太阳光的白光照射下产生了较大的光电流响应,具有出色的光电转化效率和光电化学性能。3、聚吡咯/硅纳米纤维复合材料:基于天然纤维素表面的羟基和硅烷的共价作用,通过溶胶-凝胶法制备二氧化硅凝胶薄膜/纤维素复合材料,在空气中煅烧得到二氧化硅纳米管材料,再通过镁热还原反应将二氧化硅纳米管还原为硅晶体纳米颗粒组成的硅纳米纤维材料,随后用原位化学聚合法将吸附在硅纳米纤维表面的吡咯单体聚合,得到的聚吡咯纳米颗粒均匀且完整包覆在硅纳米纤维表面。聚吡咯/硅纳米纤维复合材料复制了纤维素模板的三维多孔网络结构。将该复合材料用作锂离子电池负极的活性材料,在充放电过程中材料结构的完整性以及硅的晶体相得以很好保持,电池显示了良好的可逆比容量、循环稳定性和倍率性能。4、钒掺杂的二氧化钬复合材料:基于天然纤维素表面的羟基和钛醇盐、钒醇盐的共价作用,通过表面溶胶-凝胶的方法在滤纸纳米纤维表面层层自组装二氧化钬/五氧化二钒复合凝胶薄膜,再置于空气中分别通过火焰燃烧或煅烧的方法除去纤维素模板,得到一系列钒掺杂的二氧化钛复合材料。其中,钒掺杂比例可以通过钒醇盐和钛醇盐的摩尔比来控制。和煅烧法相比,火焰燃烧法能在一定程度上抑制二氧化钛和五氧化二钒的相分离以及晶体颗粒在相转变过程中的聚集和生长,促进了钒离子在二氧化钛晶格中的掺杂,制备得到精确复制了纤维素模板多层级结构的钒掺杂金红石型二氧化钛复合纳米纤维材料,组成纤维的纳米颗粒尺寸较小且均匀。此外,进一步研究了用煅烧法制备得到的二氧化钛材料的相转变,结果表明钒离子在二氧化钛晶格中的掺杂以及基于天然纤维素为模板的层层自组装制备方法能够显著降低二氧化钛的相转变温度,在600℃的较低煅烧温度下初始的锐钛矿型二氧化钛即可完全转变为金红石型的二氧化钛。
[Abstract]:In twenty-first Century, the rapid development of industry with huge energy consumption, mankind is faced with fossil fuels and other non renewable energy exhausting, followed by a series of serious environmental problems. Therefore, the development of new clean energy materials and make full use of solar energy and other renewable energy imminent. There are a lot of biomass resources in nature among them, the natural cellulose material with abundant yield, good biodegradability, biocompatibility, flexibility and mechanical strength, and cellulose molecules between the complex interaction gives its unique three-dimensional multi-level structure, porous structure and large surface area. Therefore, natural cellulose is an excellent biological activity of hydroxyl groups on the surface of the template. Rich variety of object materials might self assemble into cellulose surface. This paper is based on natural cellulose substances ( No ash) quantitative filter paper as the template, the self-assembly of various guest molecules on the surface of oxide cellulose single nanofiber, followed by different ways to prepare postprocessing, combined with a new type of cellulose template structure and unique object material specific functions in functional nano materials, can be used in the research field of photoelectric transformation system and lithium ion batteries, the main contents are as follows: 1, photosystem II / two porous holmium oxide nanotube network light anode system: the covalent interaction of surface hydroxyl groups of cellulose and titanium alkoxide based on titanium dioxide gel film in the surface of nanometer fiber filter paper of self-assembly, calcined in air to get rid of the cellulose template obtained an exact copy of the anatase two holmium oxide nanotubes template multilayer porous network structure. The two holmium oxide materials on the surface of the electrode substrate Modified. Then, the purified from spinach leaves with water splitting function of photosystem II (PS II) protein assembled on the electrode, successfully constructed a novel protein / semiconductor composite anode system. Because the bionic planar electrode was titanium dioxide nanotube material optimization, protein can improve the loading capacity of the electrode surface. In addition, synergistic interaction between PS protein and titanium dioxide, transfer to simulate electron transfer in Photosynthesis "Z" chain in electronic PS II protein and titanium dioxide levels. The complex light anode system has good photoelectrochemical properties. It used for the conversion of solar energy and electric power generation, light current high white light under simulated sunlight, with a certain external to drive LED lights under the condition of.2, PS / nano tubular indium tin oxide film is light anode body assembly Department of surface hydroxyl cellulose and indium alkoxides based on covalent interactions for tin alkoxide preparing indium tin oxide (ITO) gel film / cellulose composite material, calcined in air to get rid of cellulose, can obtain nano tubular ITO thin film structure of multilayer porous network to accurately reproduce the cellulose template. The material of visible light transmittance, conductivity of the indium tin make material has high adhesion. The conductive colloidal gold achieve modification of planar electrode on the electrode substrate using nano tubular ITO film material, and the PS II protein assembled in the porous network structure of ITO thin film materials, construct a new semi manual PS II / ITO nano tubular composite optical anode system. Nano tubular ITO films can effectively improve the load capacity of PS II protein in the surface of the electrode; ITO nanotube structure material and its superior The optical and electrical properties and enhance the transmission efficiency in the electronic light anode system. The composite light anode system for solar energy conversion and power generation, in the light irradiation of simulated sunlight caused by the photocurrent response is larger, with excellent photoelectric conversion efficiency and photoelectrochemical properties of PPy /.3. Silicon nano fiber composite materials: covalent interactions of natural cellulose based on surface hydroxyl groups and silane, was prepared by sol-gel silica gel film / cellulose composite material, calcined in air to obtain silica nanotubes, by magnesiothermic reduction reaction of silica nanotubes reduced to silicon nano crystal silicon nano fiber material particles, then the adsorption on the surface of silicon nano fiber polymerization of pyrrole monomer in situ chemical polymerization of polypyrrole nanoparticles to obtain uniform and complete package Coating on the surface of the fibers. The silicon nano polypyrrole / silicon nano fiber composite material copied cellulose template three-dimensional porous network structure. The composite material is used as the active material of lithium ion battery cathode material structure, in the process of charge and discharge and the integrity of the silicon crystal phase can be maintained, the battery showed good reversible capacity, cycle stability and rate performance of.4 two, holmium oxide composite vanadium doping: natural cellulose hydroxyl on the surface of titanium alkoxide and based on covalent effects of vanadium alkoxide, by surface sol-gel nano fiber filter in surface layer by layer self-assembly of two / five of two vanadium holmium oxide composite gel film, then in the air by flame method or calcined to remove the cellulose template, obtained a series of vanadium doped TiO2 composite materials. Among them, the proportion of vanadium doped by vanadium alkoxide And the mole ratio of titanium alkoxide control. Compared with the calcination method, phase separation flame combustion method can to some extent inhibit the oxidation of two titanium dioxide and five vanadium and crystal particles in the phase transition and aggregation in the process of growth, promoted vanadium doping ions in TiO2 lattice, prepared to accurately reproduce vanadium doping rutile TiO2 composite nano fiber material structure of multi grade cellulose fiber template, nano particle size is small and uniform. In addition, further study of the phase transformation of calcined TiO2 materials were prepared, the results showed that the doped vanadium ion in TiO2 lattice and layers based on natural cellulose template self-assembly preparation method can significantly reduce the phase transition temperature of TiO2 anatase TiO2 can be calcined at low initial temperature of 600 DEG C under complete turn It turns into rutile titanium dioxide.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O636.11;TM912

【参考文献】