泡沫石墨烯纳米复合材料的制备与应用研究

发布时间：2018-04-30 15:26

  本文选题：石墨烯 + 聚乙烯醇　； 参考：《东南大学》2017年硕士论文

【摘要】：泡沫石墨烯是具有三维结构的石墨烯组装体,既有石墨烯优秀的物理化学性质,又具有三维多孔结构的比表面积大、机械强度可控以及传质快速等优点。这些独特的性质使泡沫石墨烯及其复合材料备受关注。本课题采用氧化石墨烯(GO)为前驱体,制备了氧化石墨烯/聚乙烯醇(GO/PVA)三维复合材料,通过热还原法制备了 r-GO/PVA材料,并系统研究了材料的成分、微观结构及力学性能。为探索复合材料在高性能锂离子电池上的应用,本文采用水热法合成了 Sn02纳米粒子,研究了水热温度对其形貌、性能的影响。在此基础上,制备了石墨烯/二氧化锡/聚乙烯醇r-GO/SnO_2/PVA三维多孔材料,研究了其电化学性能。本论文主要研究内容和结果如下:(1)通过冷冻干燥法制备了二元复合GO/PVA泡沫材料,其内部具有均匀的孔洞,且可通过改变PVA加入量调节孔径,材料的抗压强度和弹性模量随PVA含量增加而提高。在氩气下300 ℃还原后,得到r-GO/PVA,材料的导电性能提高,强度和模量均低于同比例的GO/PVA材料。(2)采用水热法制备了 Sn02纳米材料,并对其进行系统表征。结果表明,随水热温度提高,SnO_2由纳米颗粒转变成纳米棒状结构。将240 ℃下得到的纳米棒状SnO_2用作锂电负极材料,具有较高的首次放电容量(1401 mAh/g),在500 mA/g电流密度下循环100次后,放电比容量在350 mAh/g左右。(3)将SnO_2纳米棒均匀地分散在GO溶液中,采用冷冻干燥法制备了r-GO/SnO_2/PVA,将其用作锂离子电池负极材料时,表现出优异的电化学性能。首次库伦效率大于60%,循环100次后放电比容量保持在709.9 mAh/g以上,且此材料具有优秀的倍率性能,在4A/g的电流密度下充放电,放电比容量在～500 mAh/g左右。
[Abstract]:Foamed graphene is an assembly of graphene with three dimensional structure. It has excellent physical and chemical properties, large specific surface area of three-dimensional porous structure, controllable mechanical strength and rapid mass transfer. These unique properties have attracted much attention to graphene foam and its composites. In this paper, the graphene oxide / polyvinyl alcohol (GOP / PVA) three dimensional composites were prepared by using graphene oxide (GOO) as the precursor. The r-GO/PVA materials were prepared by thermal reduction method. The composition, microstructure and mechanical properties of the composites were systematically studied. In order to explore the application of composite materials in high performance lithium-ion batteries, Sn02 nanoparticles were synthesized by hydrothermal method, and the effects of hydrothermal temperature on their morphology and properties were studied. On this basis, three dimensional porous materials of graphene / tin dioxide / polyvinyl alcohol (r-GO/SnO_2/PVA) were prepared and their electrochemical properties were studied. The main contents and results of this paper are as follows: (1) binary composite GO/PVA foam materials were prepared by freeze-drying method. The internal pores were uniform and the pore size could be adjusted by changing the amount of PVA. The compressive strength and elastic modulus of the material increase with the increase of PVA content. After reduction at 300 鈩，

本文编号：1825099