柔性氮掺杂网状碳材料的制备及其力学和电化学性能研究
发布时间：2018-07-24 10:51
【摘要】：随着可穿戴、轻薄和柔性电子产品的迅速发展,开发具有高功率、高能量密度的柔性储能器件已经成为储能领域的研究热点。然而,常规的电极制备需要加入导电剂、粘结剂和金属集流体。其中,导电剂和粘结剂是非活性成分,会降低电极的比容量,而金属集流体则会降低电极的整体能量密度和机械柔性,导致传统的储能器件无法满足柔性电子设备的要求。因此,设计和开发具有高比容量、质轻、自支撑的柔性电极材料是发展柔性储能器件的关键所在。目前,柔性电极材料遇到的瓶颈,主要体现在以下两个方面:1)材料制备方法复杂,成本较高;2)电池的电化学性能仍未达到传统锂离子电池水平,无法满足实际应用的要求。针对上述问题,本论文设计、开发了两种兼具柔性和三维多孔结构的氮掺杂网状碳材料,研究了其在氧气还原电催化(ORR)和柔性锂离子电池电极材料方面的应用,并探究其结构与性能之间的关系。具体工作如下:(1)以三聚氰胺泡沫为前驱体,采用预氧化和高温热解两步法制备了一种多孔氮掺杂碳泡沫(NCFs)。考察了预氧化过程及温度(250,300℃)对NCFs形貌、结构和性能的影响。形貌和结构表征显示,NCFs碳骨架具有较高的石墨化程度和丰富的多级孔结构,比表面积可以达到980 m2 g~(-1)。力学性能测试结果表明,NCFs在80%的压缩形变下能回复到原状而不发生任何塑性形变,具有优异的弹性性能。NCF-300~(-1)000用作ORR催化电极时,在碱性介质中表现出优越的催化活性,起始电位与商业化Pt/C催化剂相当。同时,它还具有优于Pt/C催化剂的循环稳定性和抗甲醇中毒性。如此优异的电催化性能主要归功于NCFs的多级孔结构提供了丰富的催化活性位点以及三维石墨化碳结构保证了优越的电荷传递通道。(2)采用简单的压力辅助热解法,制备了一种兼具柔性和高密度的氮掺杂碳纸(NCPs)。考察了压力大小(600,400,200和0 kPa)对NCPs结构和性能的影响。研究发现,随着压力的增大,NCP的三维网状结构越来越密集,密度和导电性逐渐升高。三点弯曲测试结果显示,NCPs具有优异的机械柔性。将NCP-600k直接用于锂电池负极材料,表现出良好的循环性能和倍率性能。在0.05和0.5 A g~(-1)的电流密度下循环200圈,NCP-600k的放电比容量分别为480和329.8 mA h g~(-1);甚至在8.0 A g~(-1)电流密度下循环500圈,放电比容量仍然能够保留126.5 mA h g~(-1),保留率可以达到98.8%。如此优异的电化学性能源于NCPs具有良好的三维导电网络,促进了电荷的高效传递;以及碳纤维骨架上的多孔结构和氮原子的掺杂提供了丰富的储锂活性位点,提高了锂离子的存储能力。
[Abstract]:With the rapid development of wearable, thin and flexible electronic products, the development of flexible energy storage devices with high power and high energy density has become a research hotspot in the field of energy storage. However, conventional electrode preparation requires the addition of conductors, binders, and metallic fluid traps. Among them, the conductive agent and binder are inactive components, which will reduce the specific capacity of the electrode, while the metal collector will reduce the overall energy density and mechanical flexibility of the electrode, resulting in the traditional energy storage device can not meet the requirements of flexible electronic equipment. Therefore, the design and development of flexible electrode materials with high specific capacity, light weight and self support is the key to the development of flexible energy storage devices. At present, the bottleneck of flexible electrode material is mainly reflected in the following two aspects: 1) the preparation method of the material is complex and the cost is high. The electrochemical performance of the battery is still not up to the level of the traditional lithium ion battery, which can not meet the requirements of practical application. In order to solve the above problems, two kinds of nitrogen-doped reticular carbon materials with flexible and three-dimensional porous structure were designed and developed in this paper. The applications of these materials in oxygen reduction electrocatalytic (ORR) and flexible lithium ion battery electrode materials were studied. The relationship between structure and performance is explored. The main works are as follows: (1) using melamine foam as precursor, a porous nitrogen-doped carbon foam (NCFs). Was prepared by pre-oxidation and pyrolysis at high temperature. The effects of preoxidation process and temperature (250300 鈩，
本文编号：2141138
[Abstract]:With the rapid development of wearable, thin and flexible electronic products, the development of flexible energy storage devices with high power and high energy density has become a research hotspot in the field of energy storage. However, conventional electrode preparation requires the addition of conductors, binders, and metallic fluid traps. Among them, the conductive agent and binder are inactive components, which will reduce the specific capacity of the electrode, while the metal collector will reduce the overall energy density and mechanical flexibility of the electrode, resulting in the traditional energy storage device can not meet the requirements of flexible electronic equipment. Therefore, the design and development of flexible electrode materials with high specific capacity, light weight and self support is the key to the development of flexible energy storage devices. At present, the bottleneck of flexible electrode material is mainly reflected in the following two aspects: 1) the preparation method of the material is complex and the cost is high. The electrochemical performance of the battery is still not up to the level of the traditional lithium ion battery, which can not meet the requirements of practical application. In order to solve the above problems, two kinds of nitrogen-doped reticular carbon materials with flexible and three-dimensional porous structure were designed and developed in this paper. The applications of these materials in oxygen reduction electrocatalytic (ORR) and flexible lithium ion battery electrode materials were studied. The relationship between structure and performance is explored. The main works are as follows: (1) using melamine foam as precursor, a porous nitrogen-doped carbon foam (NCFs). Was prepared by pre-oxidation and pyrolysis at high temperature. The effects of preoxidation process and temperature (250300 鈩，
本文编号：2141138
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