石墨烯基复合水凝胶用于超级电容器电极材料的性能研究
发布时间：2019-06-26 08:27
【摘要】：超级电容器,作为一种新颖、低价、环保、高性能的储能系统,在资源日益枯竭的今天受到了学者们的广泛关注。石墨烯水凝胶具有团聚度小、自支撑性、不用粘合剂、三维交联网络孔结构等优秀的结构特性,并且作为超级电容器电极材料,其循环寿命好,在较大的电流密度下仍可以保持原有的比电容,但是比电容较低。因此本文研究重点是通过复合来提高石墨烯水凝胶的比容量和能量密度。通过简单的水热法制备了石墨烯/碳纳米管复合水凝胶。石墨烯水凝胶拥的交联网络结构为电解液的进出以及带电离子的嵌入和脱出提供了通道,同时碳纳米管插层在石墨烯片之间还可以减少石墨烯片层的层叠现象,提高材料的电导率,并且增加了复合物的比电容。所得产物的电容量可以达到350.1 F/g,并且拥有良好的倍率特性,可以在大电流下使用。同时具有较高的能量密度,可以达到175.1 Wh/kg。并且具有良好的循环稳定性,在充放电循环一千圈后仍然可以保持第一圈充放电90%的电容量,非常具有实际应用价值。石墨烯/二氧化钒复合水凝胶是通过一步水热法制备得到的。水凝胶三维网络结构的存在降低了复合材料的电阻,同时二氧化钒的存在增加了复合材料的电容量,减少了石墨烯片的层叠现象。在两种组分协同作用下,这种复合水凝胶具有较大的比容量,其最大电容量可以达到281.5 F/g,并且循环稳定性良好,在充放电一千圈后,其电容量仍然可以保持第一次充放电电容量的95%。同时,复合物水凝胶拥有较高的能量密度,可以达到140.8 Wh/kg,这与传统电池相比具有很明显的优势。该复合物水凝胶适用于超级电容器电极材料。通过水热法制备了石墨烯水凝胶,然后采用化学浴(Chemical Bath Deposition, CBD)的方法以石墨烯水凝胶为基底生长了 NiOOH纳米片。石墨烯水凝胶的交联网络结构为电极反应提供了更多的活性位点;其三维孔结构的存在不仅避免了石墨烯片层的层叠和团聚现象,同时为电解液离子的传输提供了通道,降低了复合水凝胶的电阻。NiOOH作为赝电容有较高的比电容,但是由于生长的太少,复合水凝胶的比电容并没有太大的提高,仅由61.7 F/g提高到了 91.3 F/g。但是其循环稳定性良好,循环一千圈后,其电容量仍可以保持初始值的91.5%,有一定的实际应用价值。
[Abstract]:Supercapacitor, as a novel, low-cost, environmentally friendly and high-performance energy storage system, has been paid more and more attention by scholars when the resources are exhausted day by day. Graphene hydrogel has excellent structural characteristics, such as small agglomeration, self-support, no adhesive, three-dimensional crosslinked network pore structure and so on. As an electrode material of supercapacitor, graphene hydrogel has good cycle life and can still maintain the original specific capacitance at high current density, but the specific capacitance is low. Therefore, the focus of this paper is to improve the specific capacity and energy density of graphene hydrogel by recombination. Graphene / carbon nanotube composite hydrogel was prepared by simple hydrothermal method. The crosslinked network structure of graphene hydrogel provides a channel for electrolyte in and out of electrolyte and the embedding and stripping of charged ions. At the same time, carbon nanotube intercalation between graphene sheets can also reduce the stacking phenomenon of graphene lamellae, improve the conductivity of the material, and increase the specific capacitance of the composite. The capacitance of the product can reach 350.1 F / g, and it has good rate characteristics and can be used at high current. At the same time, it has a high energy density, which can reach 175.1 Wh/kg.. It has good cycle stability and can still maintain 90% of the capacitance of the first cycle after a thousand cycles of charge-discharge cycle, which is of great practical application value. Graphene / vanadium dioxide composite hydrogel was prepared by one-step hydrothermal method. The existence of three-dimensional network structure of hydrogel reduces the resistance of the composites, while the existence of vanadium dioxide increases the capacitance of the composites and reduces the stacking phenomenon of graphene sheets. Under the synergistic action of the two components, the composite hydrogel has a large specific capacity, its maximum capacitance can reach 281.5 F 鈮，
本文编号：2506056
[Abstract]:Supercapacitor, as a novel, low-cost, environmentally friendly and high-performance energy storage system, has been paid more and more attention by scholars when the resources are exhausted day by day. Graphene hydrogel has excellent structural characteristics, such as small agglomeration, self-support, no adhesive, three-dimensional crosslinked network pore structure and so on. As an electrode material of supercapacitor, graphene hydrogel has good cycle life and can still maintain the original specific capacitance at high current density, but the specific capacitance is low. Therefore, the focus of this paper is to improve the specific capacity and energy density of graphene hydrogel by recombination. Graphene / carbon nanotube composite hydrogel was prepared by simple hydrothermal method. The crosslinked network structure of graphene hydrogel provides a channel for electrolyte in and out of electrolyte and the embedding and stripping of charged ions. At the same time, carbon nanotube intercalation between graphene sheets can also reduce the stacking phenomenon of graphene lamellae, improve the conductivity of the material, and increase the specific capacitance of the composite. The capacitance of the product can reach 350.1 F / g, and it has good rate characteristics and can be used at high current. At the same time, it has a high energy density, which can reach 175.1 Wh/kg.. It has good cycle stability and can still maintain 90% of the capacitance of the first cycle after a thousand cycles of charge-discharge cycle, which is of great practical application value. Graphene / vanadium dioxide composite hydrogel was prepared by one-step hydrothermal method. The existence of three-dimensional network structure of hydrogel reduces the resistance of the composites, while the existence of vanadium dioxide increases the capacitance of the composites and reduces the stacking phenomenon of graphene sheets. Under the synergistic action of the two components, the composite hydrogel has a large specific capacity, its maximum capacitance can reach 281.5 F 鈮，
本文编号：2506056
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