石墨烯（复合）材料的γ-射线辐照制备方法研究

发布时间：2018-04-29 00:17

本文选题：射线辐照方法 + MnO/rGO复合材料　；参考：《中国科学技术大学》2017年硕士论文

【摘要】：由于独特的光电性能、优异的机械性能和高的比表面积,石墨烯有着非常广泛的应用。但由于石墨烯层间的范德华和π-π吸引力的作用,石墨烯易倾向于堆叠,而这则极大的抑制了石墨烯本身具有的优异性能,限制了其在大多数领域的应用。而石墨烯三维结构和其纳米复合材料因其独特的结构可以避免石墨烯层间的堆叠。目前石墨烯及其复合材料典型的合成方法包括气相沉积法、化学还原法和水热法等,但这些方法的应用因为高昂的费用、有毒还原剂的使用及苛刻的高压条件等被极大地限制。在本论文中,我们采用了一种温和且洁净的γ-射线辐照方法,对其在两种石墨烯(复合)材料中的制备进行了研究。一、在常温常压下,通过γ-射线辐照方法制备氧化亚锰/石墨烯(MnO/rGO)复合材料,用于锂离子二次电池负极。γ-射线可以辐解水产生水合电子还原高锰酸钾,产生尺寸可调的MnO颗粒,并在石墨烯的表面上均匀地分布。以上优势使γ-射线辐照还原制备的MnO/rGO复合材料有着较好的电化学性能。2 A g-1电流密度下进行500次循环后,MnO/rGO复合材料的比容量仍可高达1687 mA h g-1。在0.2 Ag-1的高电流密度下,MnO/rGO复合材料的比容量可高达2175 mAh g-1。且即使在15 Ag-1的高电流密度下,复合材料的比容量仍可达546mAh g-1,约为商用石墨负极的1.5倍。因此,γ-射线辐照还原在制备电池材料方面将是一种很有前景的方法。二、在无表面活性剂的条件下,采用简单的γ-射线辐射法合成石墨烯海绵结构。通过在氧化石墨烯(GO)分散液中加入醋酸和氨水调节GO在溶剂中的分散状态,分析其对三维石墨烯海绵形成的影响。还通过在石墨烯上负载1.1×104 cm cm-2的CNT(5 wt.%)来增强石墨烯海绵的压缩性能。我们也通过控制GO的浓度来调节石墨烯海绵的密度,以满足不同的需求。石墨烯海绵的密度可低至5.0 mg cm-3,孔隙率高达99.8%,电导率仅为0.012 S cm-1。我们对海绵进行了压缩性能测试,结果显示80%形变下线性部分的长度达73.5%,且电阻率在压缩和回弹时随形变呈近线性变化;50%形变下,800次循环后样品仍可保持初始形貌,应力保留率在85%左右。该法合成的石墨烯海绵由于超低的电导率和极好的压缩性能在弹性导体、压力传感器等方面有较好的应用前景。
[Abstract]:Graphene has a wide range of applications due to its unique optoelectronic properties, excellent mechanical properties and high specific surface area. However, due to the van der Waals and 蟺-蟺 attraction between graphene layers, graphene tends to be stacked, which greatly inhibits the excellent properties of graphene itself and limits its application in most fields. Because of its unique structure, graphene three-dimensional structure and its nanocomposites can avoid the stacking between graphene layers. At present, the typical synthesis methods of graphene and its composites include vapor deposition, chemical reduction and hydrothermal methods. However, the application of these methods is greatly limited due to the high cost, the use of toxic reductants and harsh high pressure conditions. In this thesis, a mild and clean 纬-ray irradiation method was used to study the preparation of 纬-ray radiation in two graphene (composite) materials. Firstly, at room temperature and atmospheric pressure, the manganese oxide / graphene oxide MNO / rGO) composite material was prepared by 纬 -ray irradiation method, which was used in lithium ion secondary battery negative electrode. 纬 -ray can radiate water to produce hydrated electron reduction potassium permanganate to produce MnO particles of adjustable size. And distributed uniformly on the surface of graphene. The above advantages make the MnO/rGO composites prepared by 纬 -ray irradiation have better electrochemical performance. The specific capacity of MNO / R go composites can still reach 1687 Ma / g ~ (-1) after 500 cycles at current density of 2.2A g ~ (-1). Under the high current density of 0.2 Ag-1, the specific capacity of the MNO / RGO composite can be up to 2175 mAh g ~ (-1). Even at the high current density of 15 Ag-1, the specific capacity of the composite is still up to 546mAh g-1, which is about 1.5 times of the commercial graphite anode. Therefore, 纬-ray irradiation reduction will be a promising method in the preparation of battery materials. Secondly, graphene sponge structure was synthesized by simple 纬-ray radiation under the condition of no surfactant. The influence of acetic acid and ammonia water on the formation of three-dimensional graphene sponge was analyzed by adding acetic acid and ammonia into the dispersion solution of graphene oxide to adjust the dispersion state of go in solvent. The compression properties of graphene sponges were also enhanced by loading 1. 1 脳 10 ~ 4 cm cm-2 CNT(5 wt. on graphene. We also control the concentration of go to adjust the density of graphene sponge to meet different needs. The density of graphene sponge is as low as 5.0 mg / cm ~ (-3), the porosity is as high as 99.8 and the conductivity is only 0.012 S / cm ~ (-1). The compressive properties of sponge were tested. The results showed that the length of linear part in 80% deformation was 73.5%, and the resistivity changed nearly linearly with deformation (50%). After 800 cycles, the initial morphology of the sample could be maintained. The stress retention rate is about 85%. The graphene sponge synthesized by this method has a good application prospect in elastic conductors, pressure sensors and so on due to its ultra-low conductivity and excellent compression properties.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;TB33

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