基于细菌纤维素的柔性电极的制备及在超级电容器中的应用

发布时间：2018-04-01 08:00

本文选题：柔性电极　切入点：细菌纤维素　出处：《哈尔滨工业大学》2017年硕士论文

【摘要】：柔性的储能装置正在引起越来越多的关注,因为它们具有一些独特的且极具潜力优点,如灵活性,形状多样性,重量轻等,这些特性使其可以应用在便携式,柔性,甚至可穿戴的电子设备中。在这些选择中,超级电容器,通常称为电化学电容器,由于其高功率,充放电速率快,长循环寿命和低成本而被广泛认为是有前景的能量存储系统。显然,实现柔性储能装置的关键挑战是具有良好机械性能的可弯曲基体的选择和设计,以及制造具有高容量和优良导电性的柔性电极材料。作为已工业化生产的廉价生物质材料,细菌纤维素(BC)具有三维的相互交联的纳米纤维网络结构和丰富的表面羟基,这由宽度为20-100nm的纳米纤维随机组合而成,从而提供足够的比表面积,丰富的孔隙结构和高拉伸强度。考虑到这些优点,BC被用作支撑基底时,柔性电极具有极好的亲水性和高质量负载。在本文中,通过简便且低成本的方法制备了两种具有大质量负载,高面积比电容和优异机械性能的柔性电极,并考察了其电化学性能。聚吡咯(PPy)对柔性电容器而言是极有前景的赝电容电极材料。其有竞争力的优点包括高导电性,易于合成,低成本以及好的环境稳定性。然而,由于PPy较差的机械性能,直接使用其作为柔性电极材料会严重阻碍其应用。在此,本文通过在石墨烯/碳纳米管/细菌纤维素(GN/CNT/BC)电极上电化学聚合PPy薄膜制备了一种自支撑的导电薄膜电极。与化学聚合PPy相比,电化学聚合PPy将直接生长并附着在电极表面上,从而可直接控制PPy的质量和结构。此外,本文系统地研究了掺杂剂浓度和PPy负载量对电极性能的影响。在Na2SO4和H2SO4电解质中,所得到的PPy/GN/CNT/BC电极分别具有811.4 m F cm-2和1191 m F cm-2的良好面积比电容。对于N-ASPC/GN/BC而言,来源丰富的生物质废物(柚子皮)被选中作为碳前驱体。受益于其强大的溶液吸收能力和固有的结构,我们开发了一种无模板的巧妙策略,通过两个简单的步骤即先掺杂后活化,从而制备出具有高比表面积和孔隙率的N掺杂多孔活性碳。尽管其质量负载高(8 mg cm-2),该纸电极仍然具有超高的机械拉伸强度和良好的导电性,达到32 MPa和1550 S m-1。当在三电极体系中评估时,N-ASPC/GN/BC电极在6 mol L-1 KOH中可提供高达2004 mF cm-2(250.5 F g-1)的优异面积比电容。
[Abstract]:Flexible energy storage devices are attracting more and more attention because of their unique and potential advantages, such as flexibility, variety of shapes, light weight, etc., which enable them to be used in portable, flexible, etc.Even wearable electronic devices.Among these options, supercapacitors, commonly known as electrochemical capacitors, are widely regarded as promising energy storage systems because of their high power, high charge / discharge rate, long cycle life and low cost.Obviously, the key challenges to achieve flexible energy storage are the selection and design of flexible matrix with good mechanical properties, and the fabrication of flexible electrode materials with high capacity and excellent conductivity.As a cheap, industrially produced biomass material, bacterial cellulose (BC) has a three-dimensional cross-linked nanofiber network and abundant surface hydroxyl groups, which are randomly composed of nanofibers having a width of 20-100nm.Thus providing sufficient specific surface area, rich pore structure and high tensile strength.Considering these advantages, the flexible electrode has excellent hydrophilicity and high mass load when it is used as a supporting substrate.In this paper, two kinds of flexible electrodes with large mass load, high area specific capacitance and excellent mechanical properties were prepared by a simple and low-cost method, and their electrochemical properties were investigated.Polypyrrole is a promising pseudo-capacitor electrode material for flexible capacitors.Its competitive advantages include high electrical conductivity, ease of synthesis, low cost and good environmental stability.However, due to the poor mechanical properties of PPy, its direct use as flexible electrode material will seriously hinder its application.In this paper, a self-supporting conductive thin film electrode was prepared by electrochemical polymerization of PPy film on graphene / carbon nanotube / bacterial cellulose (GNN / CNT / BC) electrode.Compared with chemically polymerized PPy, the electrochemical polymerized PPy will grow directly and attach to the electrode surface, which can directly control the quality and structure of PPy.In addition, the effects of dopant concentration and PPy loading on the electrode performance were studied systematically.In Na2SO4 and H2SO4 electrolytes, the obtained PPy/GN/CNT/BC electrode has a good area specific capacitance of 811.4 MF cm-2 and 1191 MF cm-2, respectively.For N-ASPC/GN/BC, source-rich biomass waste (pomelo peel) was chosen as a carbon precursor.Benefiting from its strong solution absorption capacity and inherent structure, we developed a template free ingenious strategy through two simple steps, that is, doping first and then activating,Thus N doped porous activated carbon with high specific surface area and porosity was prepared.In spite of its high mass loading of 8 mg cm-2, the paper electrode still has high mechanical tensile strength and good electrical conductivity, reaching 32 MPa and 1550 Sm-1.When evaluated in a three-electrode system, N-ASPC / GNR / BC electrode can provide an excellent area specific capacitance of up to 2004 MF cm-2(250.5 F g -1 in 6 mol L-1 KOH.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O636.11;TM53

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