基于蚕砂制备氮磷硫自掺杂纳米碳材料及其电化学性能研究

发布时间：2018-05-11 19:28

本文选题：超级电容器 + 锂硫电池　；参考：《南昌大学》2017年硕士论文

【摘要】：近些年来,由于环境污染和能源短缺问题加剧,“新能源”一词已然成为热点词汇。各国研究者们逐渐将越来越多的精力投入到新能源技术研究和新能源材料开发当中。新能源主要可分为两个方面,即新能源获取和新能源存储。新能源存储又可大致分为电池和电容器两大块。随着可穿戴电子设备、新能源汽车等领域的快速发展对储能设备高能量密度、大功率密度以及安全稳定等特性提出了更高的要求,超级电容器和锂硫电池渐渐成为研究热点,尤其是可用作超级电容器和锂硫电池电极材料的多孔碳纳米材料。本文选用生物质天然蚕砂用作碳源,通过不同的方法制备出具有丰富多孔结构和高比表面积的生物质基多孔碳纳米材料,并研究了其电化学特性。主要内容如下:(1)通过180℃反应12小时水热碳化,随后经过氢氧化钾活化后成功制备了多孔碳纳米材料。利用XRD、XPS、EELS表征其成分和物相;利用SEM和TEM对其形貌结构进行分析;利用氮气吸附-脱附曲线对其比表面积和孔径分布进行了表征。结果表明,水热法制备出的碳材料为纳米网络结构,自掺杂有少量的氮、磷、硫等元素。除此之外,所制备的材料具有大量微孔,以及一定量的介孔和大孔,比表面积高达2258.45 m2·g~(-1)。将其用作双电层超级电容器电极后,表现出良好的超电容特性。在1 mA·cm~(-2)低电流密度条件下,其面积比电容高达974.44 mF·cm~(-2),即使在100 mA·cm~(-2)超高电流密度条件下其面积比电容依然高达444.44 mF·cm~(-2);在0.333 A·g~(-1)低电流密度条件下,其质量比电容高达324.81 F·g~(-1),在33.333 A·g~(-1)超高电流密度条件下其质量比电容也达到了148.15F·g~(-1),表现出了良好的倍率性能。(2)通过在惰性气体保护条件下900℃高温碳化3小时,随后经过氢氧化钾活化后成功制备了多孔碳纳米片材料。利用XRD、XPS、EELS对其成分和物相;利用SEM和TEM对其形貌结构进行分析;利用氮气吸附-脱附曲线对其比表面积和孔径分布进行了表征。结果表明,高温碳化法制备出的碳材料为纳米片结构,这与水热法制备的目标产物的形貌结构具有很大差别。高温碳化法制备的碳材料同样自掺杂有少量的氮、磷、硫等元素。氮气吸附-脱附等温曲线表明制备的碳材料同样具有大量微孔,以及一定量的介孔和大孔。将其用作双电层电容器电极材料后,在1 mA·cm~(-2)低电流密度条件下,其面积比电容高达716.67 mF·cm~(-2),即使在100 mA·cm~(-2)超高电流密度条件下其面积比电容依然高达444.44 mF·cm~(-2)。在0.333 A·g~(-1)低电流密度条件下,其质量比电容高达238.89F·g~(-1),在33.333 A·g~(-1)超高电流密度条件下其质量比电容也达到了148.15 F·g~(-1),表现出了优异的倍率性能。另外,将其与单质硫复合后用作锂硫电池的正极,表现出620.1 mA·h·g~(-1)(60%硫)和656.6 mA·h·g~(-1)(70%硫)的首次放电比容量,远高于单质硫作正极的首次放电比容量125.1 mA·h·g~(-1)。在0.2 C条件下,经过100次循环后,碳硫复合材料的容量保持率依然高达88%(60%硫)和92%(70%硫),表现出了良好的循环稳定性能。
[Abstract]:In recent years, because of the aggravation of environmental pollution and energy shortage, the term "new energy" has become a hot vocabulary. Researchers in various countries are gradually putting more and more energy into the research of new energy technology and the development of new energy materials. New energy can be divided into two aspects, namely, new energy acquisition and new energy storage. With the fast development of wearable electronic equipment and new energy vehicles, the high energy density, high power density and safety and stability of the energy storage equipment are raised with the fast development of the wearable electronic equipment. The supercapacitors and lithium sulfur batteries have gradually become the hot spots, especially for super electricity, which can be used as super electricity. Porous carbon nanomaterials of container and lithium sulfur battery electrode materials. In this paper, biomass natural silkworm sand used as carbon source was used to prepare porous carbon nanomaterials with rich porous structure and high specific surface area by different methods, and their electrochemical properties were studied. The main contents are as follows: (1) 12 hour hydrothermal reaction through 180 C The porous carbon nanomaterials were prepared after the activation of potassium hydroxide. The composition and phase of the porous carbon were characterized by XRD, XPS and EELS. The morphology and structure were analyzed by SEM and TEM, and the specific surface area and pore size distribution were characterized by nitrogen adsorption desorption curve. The results showed that the carbon materials prepared by hydrothermal method were nanoscale. The network structure has a small amount of nitrogen, phosphorus, sulfur and other elements. In addition, the prepared materials have a large number of micropores, as well as a certain amount of mesoporous and large pores, with a specific surface area up to 2258.45 m2. G~ (-1). After being used as the electrode of a double layer supercapacitor, it shows a good supercapacitor property. Under the low current density of 1 mA. Cm~ (-2), The area is up to 974.44 mF. Cm~ (-2). Even under the ultra high current density of 100 mA. Cm~ (-2), its area is still up to 444.44 mF. Cm~ (-2). Under the low current density of 0.333 A. G~ (-1), the mass ratio of the capacitance is 324.81. The mass is also higher than the capacitance under the condition of the 33.333 ultra high current density. 148.15F. G~ (-1) showed good multiplier performance. (2) the porous carbon nanoscale materials were prepared by carbonization at 900 C for 3 hours under the inert gas protection and then activated by potassium hydroxide. XRD, XPS, EELS were used to analyze their composition and phase, and the morphology and structure were analyzed with SEM and TEM, and nitrogen adsorption was used - The surface area and pore size distribution are characterized by the desorption curve. The results show that the carbon materials prepared by high temperature carbonization are nanoscale structure, which is very different from the morphology and structure of the target products prepared by hydrothermal method. The carbon materials prepared by high temperature carbonization also have a small amount of nitrogen, phosphorus, sulfur and other elements. The isothermal curve shows that the prepared carbon material also has a large number of micropores and a certain amount of mesoporous and large pores. After being used as the electrode material of the double layer capacitor, the area is up to 716.67 mF. Cm~ (-2) under the condition of low current density of 1 mA. Cm~ (-2). Even at the ultra high current density of 100 mA. Cm~ (-2), the area is higher than the capacitance. It is up to 444.44 mF. Cm~ (-2). Under the condition of low current density of 0.333 A. G~ (-1), its mass is as high as 238.89F. G~ (-1). Under the condition of 33.333 A. G~ (-1), the mass ratio of the capacitance is 148.15. The excellent doubling performance is shown. In addition, it is combined with the elemental sulfur as the positive pole of the lithium sulfur battery. The first discharge specific capacity of 620.1 mA. H. G~ (-1) (60% sulfur) and 656.6 mA. H. G~ (-1) (70% sulfur) was shown to be far higher than the first discharge ratio of the elemental sulfur as the positive electrode of 125.1 mA H. G~ (-1). After 100 cycles, the capacity retention rate of the carbon sulfur composite was still up to 88% (60% sulphur) and 92% (70% sulfur), showing good performance. Cycle stability performance.

【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;TB383.1

【参考文献】