碳纳米管修饰金属硫化物的制备及其在储能器件中的应用

发布时间：2018-08-30 20:50

【摘要】：随着全球能源消耗的日益增长和环境的迅速恶化,开发清洁新能源受到各国科学家的广泛关注。超级电容器作为一种新型储能装置,具有功率密度高、充放电速度快、循环寿命长和对环境友好等优点,被广泛应用于各大领域。随着便携式电子产品的柔性化和轻薄化,开发柔性全固态超级电容器就成了研究热点。超级电容器性能的好坏取决于电极材料的选取,过渡金属硫化物因其理论容量高,导电性好等优点,得到广泛应用。碳纳米管(CNT)具有很好的柔韧性和机械稳定性,通常被当作支架来构筑混杂结构。因此,把CNT与过渡金属硫化物有效的结合起来,既提高器件的柔韧性,又提高了比容量。本论文以硫化铜(CuS)、硫化锌(ZnS)和硫化锰(MnS)与CNT为核心,采用简单的水热合成法成功制备了形貌各异的复合纳米材料,并将其应用在柔性全固态超级电容器中,展现出优异的电化学性能。本论文主要研究成果如下:(1)通过工艺简单的两步水热合成法在CNT外围均匀生长一层CuS纳米针,把合成的CuS@CNT复合纳米材料用于超级电容器中,在1 A g-1的电流密度下,比电容高达566.4 F g-1。进一步把硫与CuS@CNT复合,合成S@CuS@CNT复合材料用于锂硫电池中。当电流密度为0.1 C时,电池容量达到1019 mA h g-1。(2)通过基于模板的简单水热法在CNT外围成功合成了一层超薄ZnS纳米片,构成ZnS@CNT复合材料。通过改变Zn(NO3)2的浓度和水热反应时间,展示了超薄ZnS纳米片的形成过程。又通过与单纯的ZnS纳米球对比,ZnS@CNT拥有更大的比表面积,有利于离子在电解液中扩散,因而展示出了更好的电化学性能。将此电极材料组装成对称全固态超级电容器,在1 A g-1测试下比电容达到159.6 F g-1,最后把四个器件串联起来,对其充电,能点亮不同颜色的发光二极管。(3)通过低成本的水热反应成功在CNT外围均匀的生长一层γ-MnS纳米颗粒。先在CNT周围生长一层二氧化硅(Si O2),有利于γ-MnS沿CNT纵轴垂直生长,最后加入硫化钠(Na2S),既提供硫源同时又能去除Si O2。改变水热反应时间,实现了γ-MnS@CNT形貌各异的可控合成。将材料用于超级电容器中,在0.5 A g-1测试下比电容高达641.9 F g-1,对其进行3000圈充放电后,容量保持率高达94.6%。最后组装成对称柔性全固态超级电容器,也展现出了优异的电化学性能。
[Abstract]:With the increasing global energy consumption and the rapid deterioration of the environment, the development of clean new energy has been widely concerned by scientists all over the world. As a new type of energy storage device, supercapacitor is widely used in many fields because of its high power density, high charge and discharge speed, long cycle life and environmental friendliness. With the flexibility and thinning of portable electronic products, the development of flexible all-solid-state supercapacitors has become a research hotspot. The performance of supercapacitors depends on the selection of electrode materials. Transition metal sulfides are widely used because of their high theoretical capacity and good conductivity. Carbon nanotubes (CNT) have good flexibility and mechanical stability and are often used as scaffolds to construct hybrid structures. Therefore, the combination of CNT and transition metal sulfides can not only improve the flexibility of the devices, but also improve the specific capacity. In this thesis, copper (CuS), zinc sulfide (ZnS) and manganese sulfide (MnS) and CNT (manganese sulfide) were used as core materials to prepare composite nanomaterials with different morphologies by hydrothermal synthesis method, and they were used in flexible all-solid supercapacitors. Show excellent electrochemical performance. The main research results of this thesis are as follows: (1) A layer of CuS nanowires was uniformly grown on the periphery of CNT by a simple two-step hydrothermal synthesis method. The synthesized CuS@CNT nanocomposites were used in supercapacitors at the current density of 1 Ag ~ (-1). The specific capacitance is up to 566.4 F g -1. Furthermore, S@CuS@CNT composite was synthesized by combining sulfur with CuS@CNT and used in lithium sulfur battery. When the current density is 0. 1 C, the capacity of the cell reaches 1019 mA h g -1. (2) an ultrathin ZnS nanocrystalline was synthesized on the periphery of CNT by a simple hydrothermal method based on template. By changing the concentration of Zn (NO3) 2 and hydrothermal reaction time, the formation process of ultrathin ZnS nanoparticles was demonstrated. Compared with the pure ZnS nanospheres, it has a larger specific surface area, which is conducive to the diffusion of ions in the electrolyte, thus showing a better electrochemical performance. The electrode material was assembled into a symmetrical all-solid supercapacitor, and the specific capacitance reached 159.6 F g-1 under 1 A g ~ (-1) test. Finally, the four devices were connected in series and charged. Light emitting diodes of different colors can be illuminated. (3) A layer of 纬 -MnS nanoparticles was successfully grown on the periphery of CNT by low cost hydrothermal reaction. A layer of silicon dioxide (Si O 2) was grown around CNT, which was beneficial to the vertical growth of 纬 -MnS along the longitudinal axis of CNT. Finally, the addition of sodium sulfide (Na2S) provided both sulfur source and Si O 2 removal. The controllable synthesis of 纬 -MnSCNT with different morphologies was achieved by changing the hydrothermal reaction time. When the material is used in supercapacitor, the specific capacitance is up to 641.9 F g ~ (-1) under 0.5 A g ~ (-1) test. After 3000 cycles of charge and discharge, the capacity retention rate is as high as 94.6%. Finally, symmetrical flexible all-solid state supercapacitors were assembled and showed excellent electrochemical performance.
【学位授予单位】：信阳师范学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TM53

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