基于π共轭储能材料的制备与电化学性能研究

发布时间：2018-03-05 14:15

  本文选题：π共轭材料　切入点：锂离子电池　出处：《哈尔滨工业大学》2015年博士论文　论文类型：学位论文

【摘要】：传统化石能源的广泛使用带来了环境的污染和资源的枯竭,以太阳能和风能为代表的可再生能源的利用日益受到广泛的关注,同时发展与之配套的储能系统是解决上述可再生能源间歇性和分散性缺点的关键。作为储能系统的核心,开发一种具有高储能密度、长循环寿命和快速充放电能力的储能电极材料就显得尤为重要和急迫。在本论文工作中,基于π共轭体系材料在储能方面的优势,以π共轭材料的结构优化设计为导向,制备一系列基于π共轭体系复合储能材料,旨在提升储能材料的电化学综合特性,具体包括如下几个方面内容:(1)基于石墨烯(GNs)与亚甲基蓝(MB)染料分子间的π-π相互作用,使染料分子吸附在石墨烯表面,同时限制石墨烯片层重新堆垛。这种处理方法,在去除染料污染物的同时,将其废弃物资源化利用,得到了一种新型的超级电容材料。该材料在1 A/g充放电倍率下,经过800次循环,比电容依然可以保持在187 F/g,电容保持率大于98%。(2)发展了一种溶剂热自组装方法制备了纳米簇的Fe_3O_4/GAs复合材料,Fe_3O_4纳米簇均匀地分散在石墨烯气凝胶三维导电网络中,其中Fe_3O_4纳米簇减少了锂离子传输的路径,有利于充放电过程中锂离子的快速输运,多孔的石墨烯气凝胶保证了活性物质与电解液充分的接触并有效地缓冲了电极的体积膨胀,使得Fe_3O_4/GAs复合电极的倍率及循环性能都得到了极大的改善。该材料在0.5 C、12 C和35 C的倍率下放电,放电容量分别为1221、392和118 mAh/g。在6C的放电倍率下,经300次充放电循环,Fe_3O_4/GAs复合电极材料依然保持着577 mAh/g的放电容量。(3)在发展的溶剂热自组装方法的基础上,针对SnO_2材料的特点,进一步发展了一种稳定电化学界面的方法策略。在制备的过程中,原位自组装生成的碳包覆在二氧化锡纳米颗粒表面,形成SnO_2@C纳米簇,由于界面上碳修饰层的存在,稳定了电化学界面,在随后的制备过程中,SnO_2@C纳米簇均匀地分散在硫掺杂的石墨烯气凝胶网络中,最终成功构建了SnO_2@C@S-GAs材料,硫掺杂石墨烯气凝胶的三维导电网络,有利于锂离子、电子的快速传输和与电解液的充分接触。该材料展示出了非常优异的倍率和循环稳定性能。在0.8、1.6、4.0、8.0和16.0A/g的电流密度下,放电容量分别为721、594、510、398和271 mAh/g。在4 A/g放电状态下,经1000次充放电循环后放电容量仍然高达537 mAh/g。(4)采用喷墨打印的方法,以PEDOT:PSS作为导电墨水,在柔性基底构筑图案化超级电容器,该方法突破了传统的图案制备方法存在制备周期长、步骤繁琐等局限,同时代替了以往方法必须采用的贵金属做为引线。所制备的柔性器件展示出了很好的柔性和电容放电特性,在0.1 mA/cm~2的电流密度下,电容值为2.8mF/cm~2,在20 mV/s的扫速下具有高达6.2 mF/cm~2的电容值。
[Abstract]:The widespread use of traditional fossil energy has brought about environmental pollution and depletion of resources. The use of renewable energy, represented by solar and wind energy, has attracted increasing attention. At the same time, the development of the associated energy storage system is the key to solve the problem of intermittent and decentralized renewable energy. As the core of the energy storage system, a kind of energy storage system with high energy storage density is developed. In this paper, based on the advantages of 蟺 conjugated materials in energy storage, the structure optimization design of 蟺 conjugated materials is taken as the direction. A series of composite energy storage materials based on 蟺 -conjugated system were prepared to improve the electrochemical properties of energy storage materials, including: 1) based on the 蟺-蟺 interaction between graphene (GNS) and methylene blue (MBM) dyes. The dye molecules are adsorbed on the surface of graphene, and the restacking of graphene lamellae is limited. A new type of super capacitor material is obtained, which goes through 800 cycles at a charge / discharge rate of 1 A / g. The specific capacitance can still be kept at 187 F / g, and the capacitance retention ratio is greater than 98. 2) A solvothermal self-assembly method has been developed to prepare nanoclusters of Fe_3O_4/GAs composites, such as Fe3O4 nanoclusters, which are uniformly dispersed in the graphene aerogel three-dimensional conductive network. Among them, Fe_3O_4 nanoclusters reduce the path of lithium ion transport, which is conducive to the rapid transport of lithium ions during charge and discharge. The porous graphene aerogel ensures sufficient contact between the active material and the electrolyte and effectively buffers the volume expansion of the electrode. The performance of Fe_3O_4/GAs composite electrode was greatly improved at the rate of 12 C and 35 C, and the discharge capacity was 1221 渭 g / g and 118 mg / g, respectively, at the discharge rate of 6 C, and the discharge capacity of the composite electrode was 122mAh/ g at the rate of 12 鈩，

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