摘要现如今,能源危机已愈演愈烈,开发新能源材料及材料的循环利用已越来越重要。目前,众多研究者都将目光投向了锂离子电池和超级电容器。经过多年的研究,许多材料都表现出了优异的性能,而 Fe3O4 @ C 复合材料作为其中的佼佼者,以其良好的结构稳定性、循环稳定性和倍率性能更是引起了广泛的关注。本论文尝试利用废弃塑料制品作为碳源制备Fe3O4@C复合材料,实现资源可再生利用,同时缓解大量废弃塑料制品处理困难的现状。87324
本论文利用高温催化裂解技术,将二茂铁和多种高分子聚合物不同比例混合,分别在 500 ℃、600 ℃、700 ℃下高温煅烧,得到多种碳基复合材料,对得到的产物的组成、结构进行了表征并测试其电化学性能。最终得出结论如下:
(1)在不锈钢反应釜中,采用高温催化裂解技术, 采用聚苯乙烯、聚对苯二甲酸乙二醇酯、聚丙烯等塑料为碳源,以二茂铁为催化剂,制备出了不同形貌和结构的碳基复合材料。
(2) 表征结果表明,以聚对苯二甲酸乙二醇酯为碳源,制备得到的产物为Fe3O4@C复合材料,其形貌为一维蠕虫状,其形貌产率高达90%以上,一维结构的长度为几微米到几十微米,直径约为800 纳米,其中碳壳中Fe3O4纳米颗粒的直径为80-200纳米,碳壳的厚度约为300纳米。
(3) 将上述制备得到的Fe3O4@C复合材料作为电极材料,测试了其电化学性能。作为锂离子电池负极材料,0。5 A/g电流密度下,第一圈充放电循环中达到最大放电容量,为991。4 mAh/g,第二圈放电容量为646。3 mAh/g,经过50圈充放电循环后,其可逆容量为577。2 mAh/g,样品容量保持率维持在58。2 %;作为超级电容器电极材料,在 0。5 A/g 的电流密度下,经过 500 圈循环后,其比电容仍达到 49。1 F/g。以上结果表明,此种Fe3O4@C复合材料作为电极材料表现出良好的循环稳定性。 毕业论文关键词:催化裂解技术,Fe3O4@C复合材料,电化学性能,锂离子电池,超级电容器
Abstract With the dwindling of petroleum resources and the increasing consumption for energy, developing alternative fuels for sustainable world economics are urgently needed。 Many researchers are paying atention to lithium-ion battery and supercapacitors。 Many transition metal oxides nanoparticles have been employed as lithium ions batteries and supercapacitors electrode materials to improve their properties, and Fe3O4@C composites as one of the best materials, are attracting wide attention because of its good structural stability, rate capability and cycle stability。 This thesis attempts to use discarded plastic products as carbon resources to prepare Fe3O4@C composites, and achieve resource recycling, which provides a new idea for the disposal of waste plastics。
In this thesis, several carbon based composites were prepared by catalytic pyrolysis of waste plastics using ferrocene as catalyst at 500 ℃、600 ℃、700 ℃。 The compositions, morphologies, structures and electrochemical performances were characterized and tested:
(1) In stainless steel autoclave, carbon based composites with different morphologies and structures were prepared by catalytic pyrolysis using polystyrene (PS), polyethylene glycol terephthalate (PET) and polypropylene (PP) as carbon resources, ferrocent as catalyst。
(2) Uniform self-assembly Fe3O4@C core-shell structures have been prepared through catalytic decomposition of waste PET。 The results indicate that the products are extremely abundant one-dimensional structures with several micrometers to tens of micrometers in length and the diameter of about 800 nm。 The diameter of Fe3O4 nanoparticles inside the carbon shell is in the range of 80-200 nm, and the Fe3O4 nanoparticles are self-assembled into one-dimensional necklace-shaped structures。 The thickness of carbon shells is about 300 nm。