石墨烯水凝胶及钴镍（锰）层状氢氧化物的制备与电化学性质的研究

发布时间：2018-06-20 21:05

本文选题：超级电容器 + 石墨烯水凝胶　；参考：《河北大学》2017年硕士论文

【摘要】：超级电容器作为一种新型的储能装置具有功率高、循环寿命长和快速充放电等优点,在储能领域是一种对电池的补充,所以有着广泛的应用。传统的超级电容器电极材料根据它们的储荷原理不同主要分为两种:碳基纳米材料和赝电容材料。近年来,有储能作用的材料都获得了广泛的研究和多领域的应用。石墨烯作为一种先进的碳材料是近年来多个领域的研究热点,并且如何设计方法构筑三维的石墨烯结构受到了研究者的青睐,所以本论文研究的着眼点之一是提出新的制备石墨烯三维结构的方法。另外,类电池材料近年来在超级电容器领域应用广泛,所以本论文一方面制备了钴镍双氢氧化物微球,以探索其在混合储能装置中的应用价值;另一方面探索了三元金属离子构成的氢氧化物的电化学性质,并进一步构筑了复合电极材料以改善其性能缺陷。主要内容如下:(1)在温和的水热条件下,通过使用葡萄糖和氨水体系还原氧化石墨(GO)溶液,得到具有三维(3D)交联结构的石墨烯水凝胶(GH)。在这个反应过程中,GO纳米片自组装形成3D-GH,因为是在氨水环境下反应,所以得到的GH有N元素掺杂。此外发现,和凝胶GH-1相比较,具有更高N掺杂含量的凝胶GH-2展现出了更加有序地交联结构和更好的电化学性质。(2)通过一步溶剂热法得到了三维的纳米结构的钴镍双氢氧化物(Co1-xNix LDHs)微球,在反应过程中,使用无水乙醇作为溶剂、尿素作为碱源。通过调节钴和镍离子的投料摩尔比,最后得到了具有最佳电化学性质的Co0.2Ni0.8 LDH,其在1 A g-1下具有855.4C g-1的比容量,10 A g-1时仍然能保持777.9 C g-1。此外,以Co0.2Ni0.8 LDH为正极,活性炭(AC)为负极,制备了混合储能装置Co0.2Ni0.8 LDH//AC,其具有1.6 V的工作电压,并且展现出较高的能量密度和功率密度。(3)用原位生长法把钴镍锰混合层状氢氧化物(CoNiMn-LHCs)直接生长在泡沫镍基底上,通过调节钴镍锰离子的配比,得到了具有最高电容量的2-CoNiMn/NF,然而测试发现,在经过1000次循环之后,2-CoNiMn/NF的电容衰减到其初始电容的30.4%。因此为了改善氢氧化物的循环性能,在此基础上制备了两类复合电极材料。一是把NF浸渍在3 mg mL-1的GO溶液中反应,通过水热反应得到还原氧化石墨(RGO)膜包覆的NF,即RGO/NF;另外,我们构筑了Co3O4阵列生长在NF表面(Co3O4/NF)。最后,在RGO/NF和Co3O4/NF电极上用同样的溶剂热条件生长钴镍锰氢氧化物,得到了CoNiMn/RGO/NF和CoNiMn/Co3O4/NF复合电极材料。测试发现,复合电极材料具有更好的循环性能,特别是CoNiMn/Co3O4/NF还展现出很高的比容量,表明它在能源存储材料领域具有很大的研究价值和潜在的应用价值。
[Abstract]:As a new type of energy storage device, supercapacitor has many advantages, such as high power, long cycle life and rapid charge and discharge, so it is a supplement to battery in the field of energy storage, so it has a wide range of applications. The traditional supercapacitor electrode materials are mainly divided into two types according to their storage principle: carbon based nanomaterials and pseudo-capacitor materials. In recent years, energy storage materials have been widely studied and applied in many fields. Graphene, as an advanced carbon material, has been a hot topic in many fields in recent years, and how to design and construct three-dimensional graphene structure is favored by researchers. Therefore, one of the focus of this paper is to propose a new method for the preparation of three-dimensional structure of graphene. In addition, battery-like materials have been widely used in the field of supercapacitors in recent years, so on the one hand, cobalt and nickel double hydroxide microspheres were prepared in order to explore their application value in hybrid energy storage equipment. On the other hand, the electrochemical properties of hydroxides formed by ternary metal ions were explored, and the composite electrode materials were constructed to improve their performance defects. The main contents are as follows: (1) under mild hydrothermal conditions, a graphene hydrogel with a three-dimensional (3D) crosslinking structure was obtained by using glucose and ammonia system to reduce the oxidized graphene (GOG) solution. In this reaction process, the nanocrystalline go nanoparticles were self-assembled to form 3D-GHs. Because of the reaction in ammonia solution, the growth hormone was doped with N element. In addition, it was found that compared with the gel GH-1, The gel GH-2 with higher N-doped content showed a more orderly cross-linking structure and better electrochemical properties. (2) Three-dimensional cobalt and nickel dihydroxide Co _ 1-xNi _ x LDHs microspheres were prepared by one-step solvothermal method. Anhydrous ethanol was used as solvent and urea as alkali source. By adjusting the molar ratio of Co ~ (2 +) and Ni ~ (2 +), the best electrochemical properties of Co _ (0.2) Ni _ (0.8) LDH were obtained. The specific capacity of Co _ (0.2) Ni _ (0.8) LDH could still be kept at 777.9 C g ~ (-1) with a specific capacity of 855.4 C / g ~ (-1) at 1 A g ~ (-1). In addition, Co0.2Ni0.8 LDH / AC was prepared by using Co0.2Ni0.8 LDH as positive electrode and activated carbon acid as negative electrode. Co0.2Ni0.8 LDH / AC has a working voltage of 1.6 V. It is shown that the high energy density and power density of Co / Ni / Mn-LHCs) are grown directly on the foamed nickel substrate by in situ growth method, and the ratio of cobalt, Ni and mn ions is adjusted by adjusting the ratio of cobalt, nickel and manganese ions. The maximum capacitance of 2-CoNiMn / NFF is obtained. However, after 1000 cycles, the capacitance of 2-CoNiMn-NF decreases to 30.4g of its initial capacitance. Therefore, in order to improve the cyclic performance of hydroxides, two kinds of composite electrode materials were prepared. First, NF was impregnated in 3 mg mL-1 go solution, and the reduced graphite oxide RGO-coated NFR was obtained by hydrothermal reaction. In addition, we constructed a Co3O4 array to grow on the NF surface of Co3O4 / NFN. Finally, cobalt, nickel and manganese hydroxides were grown on RGO / NF and Co _ 3O _ 4 / NF electrodes under the same solvothermal conditions. CoNiMnR / RGO-NF and CoNiMnR / Co _ 3O _ 4 / NF composite electrode materials were obtained. It is found that the composite electrode material has better cycling performance, especially CoNiMnR / Co3O4 / NF has a high specific capacity, which indicates that it has great research value and potential application value in the field of energy storage materials.
【学位授予单位】：河北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ427.26;TM53

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