钴基硫化物电极材料的制备及其电化学性能研究
发布时间：2019-02-15 14:40
【摘要】：超级电容器是一种能够实现化学能和电能之间相互转换的新型储能装置。与传统的电容器和二次电池相比较,表现出一些优异的性能,如:功率密度高、充放电速率快、环境友好等。对于超级电容器,其核心部分是电极材料,它的好坏直接决定其性能优劣。因此,制备具有电化学性能优异的电极材料仍然是超级电容器在储能领域面临的挑战之一。本论文通过分析影响超级电容器电极材料性能的因素,构造具有多孔结构的钴基硫化物纳米材料,并展开优化以提高其电化学性能。论文工作主要包括以下几部分:1.采用离子交换水热法,制备了具有良好的导电率、畅通的离子扩散通道以及丰富的化学反应活性位点的介孔钴基硫化物材料。通过调控原料的比例以及溶剂种类,实现对其电化学性能的提高,优选出电化学性能较好的钴基硫化物材料和氮掺杂的石墨烯气凝胶,分别作为非对称超级电容器的正极和负极材料,组装混合型非对称器件,考察其综合电化学性能。2.将天然埃洛石纳米管(HL)作为模板剂,采用水热法制备了四硫代钴酸镍-埃洛石纳米管复合材料(NiCo_2S_4-HL)。在三电极体系下测试电化学性能,数据表明:在1Ag~(-1)时比容量达589Cg~(-1),并且循环1000圈后,仍保持初始比容量的83.6%,表现出良好的循环稳定性。通过在体系中引入HL,使得NiCo_2S_4与HL通过自组装形成多孔花状结构,从而助力电化学过程的展开,并最终改善提高整体电化学性能。3.以硝酸铜和氯化钴为原料,六次亚甲基四胺(HMT)作为沉淀剂,采用低温水热制备CuCo-LDH(铜钴前驱体)的纳米颗粒,前驱体分别经过高温煅烧和硫化得到产物CuCo_2O_4和CuCo_2S_4,并且对二者进行电化学性能测试。数据表明CuCo_2S_4纳米颗粒具有良好的倍率特性和循环稳定性。这是由于Cu-Co硫化物中硫的禁带宽度比氧的低,与对应的氧化物相比Cu-Co硫化物的电导率更高、活性位点更多,有效地加快了氧化还原的进行,从而改善材料综合电化学行为。4.分别以乙二醇和丙三醇为溶剂,硫脲和氨基硫脲为硫源,用“一锅法”合成四种不同形貌的铜钴硫化物,并且对四种不同形貌的样品进行物相表征和电化学性能测试。结果表明,以丙三醇为溶剂,氨基硫脲为硫源合成的Co_2CuS_4纳米颗粒,在1Ag~(-1)时,比容量达到126Cg~(-1)。
[Abstract]:Supercapacitor is a new energy storage device which can convert chemical energy and electric energy. Compared with conventional capacitors and secondary batteries, it has some excellent performances, such as high power density, high charge / discharge rate and environmental friendliness. For supercapacitors, the core part is electrode material, which directly determines the performance of supercapacitors. Therefore, the preparation of electrode materials with excellent electrochemical properties is still one of the challenges in the field of energy storage for supercapacitors. In this paper, through analyzing the factors affecting the performance of electrode materials for supercapacitors, cobalt based sulfide nanomaterials with porous structure were constructed and optimized to improve their electrochemical performance. The work of the thesis mainly includes the following parts: 1. Mesoporous cobalt-based sulfide materials with good conductivity, unblocked ion diffusion channels and abundant chemical active sites were prepared by ion exchange hydrothermal method. By adjusting the proportion of raw materials and the kinds of solvents, the electrochemical properties of cobalt based sulphide materials and nitrogen-doped graphene aerogels were selected. As positive and negative electrode materials of asymmetric supercapacitors, hybrid asymmetric devices were assembled, and their comprehensive electrochemical properties were investigated. 2. The nickel thiobalate (NiCo_2S_4-HL) nanotube composites (NiCo_2S_4-HL) were prepared by hydrothermal method using natural Ellowite nanotubes (HL) as template. The electrochemical performance was measured in a three-electrode system. The results show that the specific capacity of 589 Cg-1 is 589 Cg-1 at 1Ag-1, and the initial specific capacity remains 83.6% of the initial specific capacity after 1000 cycles, showing good cyclic stability. By introducing HL, into the system, NiCo_2S_4 and HL were self-assembled to form a porous flower-like structure, which facilitated the development of electrochemical process and improved the electrochemical performance of the whole system. The nanocrystalline CuCo-LDH (copper-cobalt precursor) was prepared by using copper nitrate and cobalt chloride as raw materials and hexa-methylene tetramine (HMT) as precipitant. The precursor was calcined and vulcanized at high temperature to obtain CuCo_2O_4 and CuCo_2S_4,. The data show that CuCo_2S_4 nanoparticles have good rate characteristics and cycle stability. This is due to the fact that the band gap of sulfur in Cu-Co sulphide is lower than that of oxygen. Compared with the corresponding oxides, Cu-Co sulfide has higher conductivity and more active sites, which effectively speeds up the redox process. In order to improve the comprehensive electrochemical behavior of materials. 4. Four copper-cobalt sulfides with different morphologies were synthesized by one-pot method with ethylene glycol and glycerol as solvents and thiourea and thiosemicarbazone as sulfur source. The results showed that the specific capacity of Co_2CuS_4 nanoparticles synthesized with glycerol as solvent and thiosemicarbazone as sulfur source was 126Cg-1 at 1Ag-1.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TM53
[Abstract]:Supercapacitor is a new energy storage device which can convert chemical energy and electric energy. Compared with conventional capacitors and secondary batteries, it has some excellent performances, such as high power density, high charge / discharge rate and environmental friendliness. For supercapacitors, the core part is electrode material, which directly determines the performance of supercapacitors. Therefore, the preparation of electrode materials with excellent electrochemical properties is still one of the challenges in the field of energy storage for supercapacitors. In this paper, through analyzing the factors affecting the performance of electrode materials for supercapacitors, cobalt based sulfide nanomaterials with porous structure were constructed and optimized to improve their electrochemical performance. The work of the thesis mainly includes the following parts: 1. Mesoporous cobalt-based sulfide materials with good conductivity, unblocked ion diffusion channels and abundant chemical active sites were prepared by ion exchange hydrothermal method. By adjusting the proportion of raw materials and the kinds of solvents, the electrochemical properties of cobalt based sulphide materials and nitrogen-doped graphene aerogels were selected. As positive and negative electrode materials of asymmetric supercapacitors, hybrid asymmetric devices were assembled, and their comprehensive electrochemical properties were investigated. 2. The nickel thiobalate (NiCo_2S_4-HL) nanotube composites (NiCo_2S_4-HL) were prepared by hydrothermal method using natural Ellowite nanotubes (HL) as template. The electrochemical performance was measured in a three-electrode system. The results show that the specific capacity of 589 Cg-1 is 589 Cg-1 at 1Ag-1, and the initial specific capacity remains 83.6% of the initial specific capacity after 1000 cycles, showing good cyclic stability. By introducing HL, into the system, NiCo_2S_4 and HL were self-assembled to form a porous flower-like structure, which facilitated the development of electrochemical process and improved the electrochemical performance of the whole system. The nanocrystalline CuCo-LDH (copper-cobalt precursor) was prepared by using copper nitrate and cobalt chloride as raw materials and hexa-methylene tetramine (HMT) as precipitant. The precursor was calcined and vulcanized at high temperature to obtain CuCo_2O_4 and CuCo_2S_4,. The data show that CuCo_2S_4 nanoparticles have good rate characteristics and cycle stability. This is due to the fact that the band gap of sulfur in Cu-Co sulphide is lower than that of oxygen. Compared with the corresponding oxides, Cu-Co sulfide has higher conductivity and more active sites, which effectively speeds up the redox process. In order to improve the comprehensive electrochemical behavior of materials. 4. Four copper-cobalt sulfides with different morphologies were synthesized by one-pot method with ethylene glycol and glycerol as solvents and thiourea and thiosemicarbazone as sulfur source. The results showed that the specific capacity of Co_2CuS_4 nanoparticles synthesized with glycerol as solvent and thiosemicarbazone as sulfur source was 126Cg-1 at 1Ag-1.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TM53
【参考文献】
相关期刊论文 前4条
1 吴水林;朱彦武;;面向可实用超级电容器的致密化碳材料研究（英文）[J];Science China Materials;2017年01期
2 张熙悦;张昊U，
本文编号：2423459
本文链接：https://www.wllwen.com/kejilunwen/cailiaohuaxuelunwen/2423459.html
