氧化铁复合纳米材料的水热制备及其超级电容特性研究

发布时间：2018-01-15 17:37

本文关键词：氧化铁复合纳米材料的水热制备及其超级电容特性研究　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：超级电容器作为一种新型的储能器件,由于具有低等效串联电阻,快速功率输出,高能量密度,大功率密度,高循环效率,长循环寿命等优异性能,目前,已成为国内外清洁能源领域的研究热点之一。氧化铁,作为一种典型的过渡金属氧化物半导体材料,其具有良好的赝电容特性。同时,与传统超级电容器材料(如,石墨烯、碳纳米管等碳基材料、氧化钌、氧化钴、氧化镍、氧化锰等过渡金属氧化物材料)相比,氧化铁纳米材料具有含量丰富、制备成本低、环境友好等众多优点。然而,单纯的氧化铁纳米材料导电性能较低,循环性能较差,比容量不高。针对上述问题,本论文通过水热法合成了不同形貌的氧化铁纳米颗粒,并将不同形貌的氧化铁纳米颗粒与石墨烯和碳纳米管进行复合,并系统研究了氧化铁/碳纳米管、氧化铁/石墨烯等氧化铁基复合纳米材料的超级电容特性。论文详细内容如下:(1)利用水热法合成出不同形貌的氧化铁纳米材料,并对材料的形貌和电化学性能进行表征。初步探讨了[H_2PO_4]~-对材料形貌的影响。实验表明磷酸二氢根离子附着在纳米晶体的侧壁,导致晶体沿[006]轴向生长。合成出的不同长径比的棒状纳米颗粒,有效增大了材料的比表面积,扩大了电解液离子与电极活性物质的接触面积,提高了电子和质子在电极材料中的传递速率,由此造成材料的电化学性能产生显著差异。结果表明长径比最小的颗粒表现出最优的比容量和稳定性。(2)利用水热法制备了多种形貌的氧化铁/多壁碳纳米管复合材料,对Fe_2O_3/MWCNT复合材料进行了结构表征和电化学性能测试。结果表明粒径较小的Fe_2O_3纳米颗粒能够生长在碳纳米管的管壁上,而粒径较大的Fe_2O_3纳米颗粒却无法在管壁上生长。粒径为5 nm、30 nm、环状、镂空环状、片状的氧化铁与碳纳米管复合后兼顾了碳纳米管和氧化铁的优点,同时又增加了材料的比表面积,加快了电子在电极材料中的传递速率,因此提高了Fe_2O_3/MWCNTs的电容性能。在电流密度为1A/g时,镂空环状氧化铁/多壁碳纳米管复合材料的比电容最高达到183 F/g并且循环性能得到明显提升,表明氧化铁/多壁碳纳米管复合材料具有良好的超级电容性能。(3)利用水热法制备了多种形貌的氧化铁/石墨烯复合纳米材料,并对Fe_2O_3/r GO复合纳米材料进行形貌表征和电化学性能测试,可以看到Fe_2O_3负载在石墨烯的层状结构上,形成二维结构,这种结构不仅缩短了离子的迁移距离,而且提高了活性材料的利用率;同时,负载有粒径为5 nm、30 nm、环状、镂空环状、片状的Fe_2O_3的石墨烯提高了材料的导电性,加快了有效离子和电荷的传输速率,从而提高了复合材料的电容性能。在电流密度为1A/g时,粒径为30 nm的Fe_2O_3/r GO比容量为135 F/g并且在经过循环充放电1000圈后其比容量保留率最高为80%,表明氧化铁/石墨烯复合材料相较纯的氧化铁和氧化铁/多壁碳纳米管复合材料,具有更好的超级电容性能。
[Abstract]:Supercapacitor is a new energy storage device, due to its low equivalent series resistance, fast power output, high energy density, high power density, high cycle efficiency, long cycle life and excellent performance, at present, has become a hot research topic in the field of clean energy field. Iron oxide, as a typical transition the metal oxide semiconductor material, which has good pseudocapacitive properties. At the same time, with the traditional super capacitor materials (e.g., graphene, carbon nanotubes and other carbon based material, ruthenium oxide, cobalt oxide, nickel oxide, manganese oxide and transition metal oxide materials), iron oxide nanomaterials have abundant preparation cost low, many advantages of environmental friendly. However, the conductive properties of pure iron oxide nano materials is low, poor cycle performance, high specific capacity. According to the above problems, this paper through the hydrothermal method with different morphologies were synthesized. Iron oxide nanoparticles, and different morphologies of composite iron oxide nanoparticles and graphene and carbon nanotubes, and the system of iron oxide / carbon nanotubes, super capacitor characteristics of iron oxide / graphene oxide composite nano materials. The detailed contents are as follows: (1) the synthesis of iron oxide nanomaterials with different morphologies by hydrothermal method and morphology and electrochemical performance of the materials were characterized. Preliminary study on the effect of [H_2PO_4]~- on the morphology of the materials. The results show that two hydrogen phosphate ions attached to the nano crystal wall, lead crystal along [006] axial growth. Different length diameter ratio of the synthesis of rod like nano particles, can increase the ratio of material the surface area, expand the contact area of the electrolyte and electrode active material, electron transfer rate and proton in the electrode material is improved, the resulting material electrochemical performance Have a significant difference. The results show that the ratio of length to diameter of the smallest particles exhibit optimal capacity and stability. (2) a variety of morphologies of iron oxide / multiwalled carbon nanotube composites were prepared by hydrothermal method on Fe_2O_3/MWCNT composites were characterized and electrochemical performance test. The results show that the smaller particle size of Fe_2O_3 nanoparticles the particles can grow in carbon nanotube walls, while the larger particle size of Fe_2O_3 nanoparticles is not on the pipe wall growth. The particle size is 5 nm, 30 nm, ring, ring hollow, flaky iron oxide and carbon nanotube composite after the advantages of carbon nanotubes and iron oxide, while the increase of material the specific surface area, accelerate the electron transfer rate in the electrode material, thereby improving the performance of Fe_2O_3/MWCNTs capacitor. When the current density is 1A/g, the hollow annular iron oxide / multiwalled carbon nanotubes composite materials than electricity The highest volume reached 183 F/g and the cycle performance has improved significantly, showed that iron oxide / multiwalled carbon nanotube composite material with super capacitor with good performance. (3) a variety of morphologies of iron oxide / graphene nanocomposites were prepared by hydrothermal method, and the Fe_2O_3/r GO composite nano materials morphology characterization and electrochemical performance testing. You can see the Fe_2O_3 load in the layered structure of graphene, a two-dimensional structure is formed, the structure not only reduces the migration distance of ions, but also improve the utilization of the active material; at the same time, loaded with the diameter of 5 nm and 30 nm, ring, ring hollow, graphene sheet Fe_2O_3 improved conductive material to speed up the transmission rate, effective ion and charge, thereby improving the capacitance properties of the composites. When the current density is 1A/g, the size of 30 nm Fe_2O_3/r GO capacity is 135 F/g and the After 1000 cycles of charge and discharge, the specific capacity retention rate is 80%, indicating that iron oxide / graphene composite material has better supercapacitor performance than pure iron oxide and iron oxide / multi walled carbon nanotube composite.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM53;TB383.1

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