过渡金属氧化物复合材料的设计合成及其储锂和光催化性能研究

发布时间：2018-03-14 02:07

本文选题：环境污染　切入点：清洁能源　出处：《江苏科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着世界经济的飞速发展,能源危机和环境污染问题日益严峻,制约着经济、社会的发展,甚至危及人类的生存。环境保护和可持续发展成为人们必须考虑的首要问题,也越来越受到人们的重视。解决环境问题的方针政策是防范和治理,比如减少化石能源的利用,加大对污染物的治理等。因此,开发绿色可再生能源和发展新型污水处理技术是当前研究的重点。锂离子电池作为一种可再生清洁能源,具有绿色环保、高能量、灵活小巧等特点,在数码产品、军事设备、医学器材、电动汽车、智能电网等领域广泛运用。随着科技的发展,人们对锂离子电池的性能提出更高要求,而高性能锂离子电池的实现依赖于其中电极材料的结构设计和性能提升。具有高比容量,高功率密度,资源丰富等优点的过渡金属氧化物材料在众多备选材料中脱颖而出,能够满足动力锂离子电池性能的要求。此外,光催化技术,是在光的作用下,通过光催化剂吸收光子能量,使得苛刻条件下进行的反应能够在温和的环境中就可以进行的一种先进绿色污水处理技术。近十几年来,过渡金属氧化物半导体光催化剂在污染物控制应用领域得到迅速发展。然而,作为一项新技术,光催化技术仍然存在着一些问题。主要表现在半导体光催化剂吸附能力差,光生载流子容易复合等。本论文针对不同研究领域存在的问题,提出相应的改善方法。具体表现在:(1)对于锂电负极材料α-MnO_2在充放电过程中存在体积膨胀而导致循环性能差的问题,本文设计了α-MnO_2@SnO_2纳米异质结复合材料,并研究了其作为锂离子电池负极材料的电化学性能。结果表明:相比较单一材料,α-MnO_2@SnO_2复合材料在100 mA g-1的电流密度下,具有更好的初始放电容量(1548 m Ah g-1)和50圈循环后恢复容量(437 mAh g-1),表现出较好的充放电循环性能。(2)对于锂电正极锰酸锂材料在充放电过程中存在锰溶解而导致的容量衰减的问题,本文设计了LiMn_2O_4纳米棒表面包覆TiO_2复合材料,研究了其作为锂离子电池正极材料的电化学性能。结果表明:LiMn_2O_4纳米棒表面包覆TiO_2复合材料在0.1 C倍率下100次循环后容量保持率为95.5%,而未包覆材料仅为81.4%,包覆材料表现出更好的循环和倍率性能。(3)对于ZnO光催化剂存在吸附能力差,光生载流子容易复合的问题,本文设计了ZnO/rGO/PANI三元复合材料,并研究了其作为光催化剂在紫外光下对甲基橙降解效率及其光电化学性能。结果表明:ZnO/rGO(7 wt.%)/PANI(10 wt.%)三元复合材料在紫外光照射60 min内对甲基橙具有99%的降解效率,而单一ZnO仅为15%。ZnO/rGO(7 wt.%)/PANI(10 wt.%)三元材料表现出更好的光电化学性质和光催化性能。
[Abstract]:With the rapid development of the world economy, the energy crisis and environmental pollution are becoming more and more serious, restricting the development of economy and society, and even endangering the survival of mankind. People pay more and more attention to it. The principles and policies to solve environmental problems are prevention and control, such as reducing the use of fossil energy, increasing the treatment of pollutants, and so on. The development of green renewable energy and the development of new sewage treatment technology is the focus of current research. Lithium ion battery, as a renewable and clean energy source, has the characteristics of green environmental protection, high energy, flexibility and small size, etc., in digital products, military equipment, etc. Medical devices, electric vehicles, smart grids and other fields are widely used. With the development of science and technology, people put forward higher requirements for the performance of lithium ion batteries. The realization of high performance lithium-ion batteries depends on the structure design and performance improvement of electrode materials. Transition metal oxide materials with high specific capacity, high power density and abundant resources stand out among many alternative materials. In addition, the photocatalytic technology, which absorbs photon energy through photocatalyst under the action of light, can meet the requirements of the performance of dynamic lithium-ion batteries. An advanced green sewage treatment technology that allows reactions under harsh conditions to be carried out in a mild environment. Transition metal oxide semiconductor photocatalysts have been developed rapidly in the field of pollutant control. However, as a new technology, there are still some problems in photocatalytic technology. Photogenerated carriers are easy to recombine, etc. In this paper, we aim at the problems in different research fields. The corresponding improvement methods are put forward, which is manifested in the problem that the volume expansion of lithium negative electrode material 伪 -MnO _ 2 leads to poor cyclic performance due to its volume expansion during charging and discharging. In this paper, a 伪 -MnO _ 2SnO _ 2 nanoheterojunction composite is designed for 伪 -MnO _ 2SnO _ 2 heterojunction composite. The electrochemical properties of 伪 -MnO _ 2SnO _ 2 composites as anode materials for lithium ion batteries were studied. The results show that compared with a single material, 伪 -MnO _ 2SnO _ 2 composite is at the current density of 100 Ma g ~ (-1). It has a better initial discharge capacity of 1548 mAh g-1) and a recovery capacity of 437 mAh g -1 after 50 cycles, showing a better charge-discharge cycle performance. In this paper, the surface of LiMn_2O_4 nanorods coated with TiO_2 composites was designed. The electrochemical properties of the composite used as cathode material for lithium ion battery were studied. The results showed that the capacity retention rate of TiO_2 composite coated with TiO_2 nanorods was 95.5 after 100 cycles at 0.1C ratio, while that of uncoated material was 81.4, and the coating material was coated. The results show that there is poor adsorption ability for ZnO photocatalyst with better cycling and ratio performance. In this paper, ZnO/rGO/PANI ternary composites are designed for easy recombination of photogenerated carriers. The photodegradation efficiency of methyl orange and its photochemical properties were studied. The results showed that the degradation efficiency of methyl orange by the three-component composite was 99% when irradiated by ultraviolet light for 60 min. The single ZnO is only 15%. ZnO / rGO7 wt.%)/PANI(10 wt.) the ternary materials exhibit better photochemical properties and photocatalytic properties.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TB33

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