杂原子掺杂三维石墨烯和复合材料的制备及其电化学性能研究

发布时间：2018-04-30 22:35

本文选题：超级电容器 + 氮掺杂三维石墨烯　；参考：《兰州理工大学》2017年硕士论文

【摘要】：三维石墨烯水凝胶是由氧化石墨烯分散液在高温高压状态下自组装而成的三维网状材料。它具有大的比表面积、良好的机械性能和高的导电率,在超级电容器、催化、吸附等领域有重要的应用。特别是在超级电容器领域,三维石墨烯能有效阻止二维石墨烯的堆叠,巨大的表面积提供了良好的双电层电容。为了进一步提高石墨烯的电化学性能,本文利用杂原子对三维石墨烯进行掺杂改性,并和聚苯胺及钴镍双金属氢氧化物复合,以期制备出具有优异电化学性能的电极材料。通过对电极材料的结构表征和电化学性能测试,探索了杂原子掺杂三维石墨烯及其复合材料的结构与性能。主要研究内容如下:(1)分别以自制的氧化石墨烯(GO);GO和尿素;GO和硫脲为原材料,采用水热法分别合成了三维还原氧化石墨烯(RGO),氮掺杂三维还原氧化石墨烯(RGN),氮、硫共掺杂三维还原氧化石墨烯(RGNS)等材料。分别测试了GO、RGO、RGN和RGNS四种材料的微观结构和电化学性能。结果表明RGO、RGN和RGNS材料均为三维多孔结构,电化学测试表明氮原子或氮、硫双原子掺杂三维石墨烯均可提高三维石墨烯的比电容和循环稳定性。(2)以尿素为还原剂和氮掺杂剂,GO和聚苯胺纳米棒(PANI-NRs)为原料,利用水热法合成了氮掺杂三维石墨烯/聚苯胺(RGNP)复合电极材料。利用FT-IR、XRD、SEM和XPS等检测手段对材料进行了表征,结果表明:PANI-NRs嵌入了氮原子掺杂的三维石墨烯层中。RGNP复合电极材料在3和30 m A cm~(-2)的电流密度下,比电容分别为589.3和472.6 F g~(-1),容量保持率为80.2%。在3 m A cm~(-2)电流密度下循环500次后,比电容保持80.5%。(3)以硫脲为还原剂和氮、硫共掺杂剂,GO和PANI-NRs为原料,利用水热法合成了氮、硫共掺杂三维石墨烯/聚苯胺(RGNSP)复合电极材料。利用FT-IR、XRD、SEM和XPS等检测手段对材料进行了表征,并且测试了复合材料的电化学性能。结果表明:复合电极材料在2和20 m A cm~(-2)的电流密度下,比电容分别为735.2和570 F g~(-1),容量保持率为77.5%。在2 m A cm~(-2)的电流密度下循环500次后,比电容保持66.7%。而未掺杂三维石墨烯的聚苯胺电极材料,在2 m A cm~(-2)的电流密度下比电容为210 F g~(-1),循环500次后,比电容保持52.5%。(4)利用共沉淀法合成了氮掺杂三维石墨烯/钴-镍双金属氢氧化物(RGN/Co Ni-LDH)。利用FT-IR、XRD、SEM和XPS等检测手段对材料进行了表征,并且测试了复合电极材料的电化学性能。结果表明:钴-镍双金属氢氧化物生长在了氮掺杂三维石墨烯的表面,并呈现出花瓣似的层状结构,这种结构可增加电极材料和电解液的接触面积,进而提高电极材料的电化学性能。在5和50 m A cm~(-2)的电流密度下,RGN/Co Ni-LDH的比电容分别为2092.3和1809.8 F g~(-1),容量保持率为86.5%,在10 m A cm~(-2)的电流密度下循环1000次后,比电容保持80%。在两电极非对称系统中,RGN/Co Ni-LDH的功率密度为101.97 W kg~(-1),能量密度为49.4Wh kg~(-1)。
[Abstract]:Three-dimensional graphene hydrogels are three-dimensional reticulated materials which are self-assembled by graphene oxide dispersion at high temperature and high pressure. It has a large specific surface area, good mechanical properties and high conductivity. It has important applications in supercapacitor, catalysis, adsorption and other fields. Especially in the field of supercapacitors, three-dimensional graphene can effectively prevent the stacking of two-dimensional graphene, the huge surface area provides a good double-layer capacitance. In order to further improve the electrochemical performance of graphene, three dimensional graphene was modified by heteratomic doping, which was combined with Polyaniline and cobalt nickel bimetallic hydroxides to prepare electrode materials with excellent electrochemical properties. The structure and properties of heteroatom doped three-dimensional graphene and its composites were investigated by means of the structure characterization and electrochemical performance test of the electrode materials. The main contents of this study are as follows: (1) the three dimensional reductive graphene oxide (RGOO) was synthesized by hydrothermal method using the self-made graphene oxide (Glucene oxide) go and Urea go and thiourea as raw materials, respectively. The three dimensional reductive graphene oxide (RGNN), nitrogen, nitrogen were synthesized by nitrogen doping. Sulfur co-doped three-dimensional reduced graphene oxide RGNS and other materials. The microstructure and electrochemical properties of RGN and RGNS were measured. The results show that both RGN and RGNS are three-dimensional porous structures, and the electrochemical measurements show that nitrogen atoms or nitrogen, The specific capacitance and cyclic stability of three-dimensional graphene can be improved by using sulfur diatomic doping. (2) Urea as reducing agent and nitrogen dopant go and Polyaniline nanorods PANI-NRs as raw materials. The nitrogen-doped three dimensional graphene / Polyaniline RGNPs composite electrode materials were synthesized by hydrothermal method. The materials were characterized by FT-IRN XRDX SEM and XPS. The results show that the. RGNP composite electrode materials are embedded in the three dimensional graphene layer doped with nitrogen atoms at the current density of 3 and 30 Ma / cm ~ (-2), the results show that: PANI-NRs are embedded in the three dimensional graphene layer doped with nitrogen atoms, and the RGNP composite electrode material has a current density of 3 and 30 Ma / cm ~ (-2). The specific capacitors were 589.3 and 472.6 FG ~ (-1), respectively, and the capacity retention rate was 80.2%. At the current density of 3 Ma / cm ~ (-2), the specific capacitance kept at 80.5 and 80.5. 3) using thiourea as reducing agent and nitrogen, sulfur co-doped with go and PANI-NRs as raw materials, nitrogen and sulfur co-doped three-dimensional graphene / Polyaniline RGNSPs composite electrode materials were synthesized by hydrothermal method. The materials were characterized by FT-IR XRD SEM and XPS, and the electrochemical properties of the composites were tested. The results show that the specific capacitance of the composite electrode is 735.2 and 570F / g ~ (-1) at the current density of 2 and 20 Ma / cm ~ (-2), respectively, and the capacity retention is 77.5%. When the current density is 2 Ma / cm ~ (-2), the specific capacitance remains 66.7 after 500 cycles. However, the specific capacitance of the undoped three dimensional graphene Polyaniline electrode material is 210 F / g ~ (-1) at the current density of 2 Ma / cm ~ (-2). After 500 cycles, the specific capacitance of the electrode is 210F / g ~ (-1). Three dimensional nitrogen-doped graphene / cobalt-nickel bimetallic hydroxide (RGNR / Co Ni-LDH) was synthesized by coprecipitation method. The electrochemical properties of the composite electrode materials were characterized by FT-IRN XRDX SEM and XPS. The results show that cobalt-nickel bimetallic hydroxides grow on the surface of nitrogen-doped three-dimensional graphene and present petal-like layered structure, which can increase the contact area between electrode material and electrolyte. The electrochemical properties of electrode materials are improved. At the current density of 5 and 50 Ma / cm ~ (-2), the specific capacitance of RGNR / Co Ni-LDH is 2092.3 and 1809.8 F / g ~ (-1), respectively, and the capacity retention is 86.5%. After 1000 cycles at the current density of 10 Ma / cm ~ (-2), the specific capacitance keeps 80 steps. In a two-electrode asymmetric system, the power density and energy density of RGNR / Co Ni-LDH are 101.97 W / kg ~ (-1) and 49.4Wh ~ (-1) 路kg ~ (-1), respectively.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;TB332

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