以木质素为碳源介孔碳及其复合材料制备和电化学中的应用

发布时间：2018-06-19 07:12

本文选题：介孔碳 + 木质素　；参考：《浙江工业大学》2015年硕士论文

【摘要】：多孔碳材料具有来源丰富、化学和热性能稳定、易于加工等优点,在超级电容器电极、固体氢存储等领域具有广泛的应用前景。介孔碳(MPCs)是多孔碳中被研究较多的品种,已被广泛用作催化剂载体及吸附剂。最近,又被拓展应用于电容器和储氢材料。木质素是植物中一种重要的支撑物质,其储存量仅次于纤维素,具有环境友好、可再生等优点。本文选用木质素为碳源,研究了介孔碳的制备、结构及其在电化学中应用。研究表明,将金属氧化物负载于介孔碳表面,可显著提高介孔碳的电子传导率和倍率性能。主要内容及结果如下:(1)介孔碳材料。本文以木质素磺酸盐作为碳源,低分子量多聚甲醛/戊二醛为交联剂,聚乙烯吡咯烷酮(PVP)为分散剂,通过水热法合成的棕色固体为碳前体。KOH/ZnCl2为扩孔剂对碳前体扩孔,最后在管式炉中煅烧制备得到了介孔碳材料。所得介孔碳材料具有较高比表面积,孔容大、孔径分布窄,并且介孔碳的碳壁已被大量石墨化,因此可作为电池的理想电极材料。组装电池后的恒流充放电测试表明介孔碳电极具有较高的比电容,且其1000次循环伏安测试结果也呈现了高的循环稳定性。这是由于介孔结构不会限制离子传输,使其具有优良的大电流充放电性能。(2)MPCs/NiO复合材料。以Ni(NO3)2·6H2O为Ni源,将上述介孔碳材料作为载体,在碱性条件下回流冷凝,使Ni+能够大量负载在介孔碳材料表面,再于管式炉中煅烧,形成以多孔碳为骨架、NiO纳米粒子良好分散的MPCs/NiO复合材料。由于NiO填充碳孔,使介孔碳的孔容及比表面积均有不同程度下降。将MPCs/NiO复合材料组装成电池,对其恒流充放电测试表明其具有较好的比电容,1000次循环伏安测试显示具有优良的循环稳定性。其原因是由于NiO的赝电容及介孔碳材料的骨架结构,提高了MPCs/NiO复合材料的电化学稳定性。
[Abstract]:Porous carbon materials have many advantages such as abundant sources, stable chemical and thermal properties, easy to process and so on. They are widely used in the field of supercapacitor electrode, solid hydrogen storage and so on. Mesoporous carbon mononuclear carbon (MPCs) has been widely used as catalyst carrier and adsorbent. Recently, it has been applied to capacitors and hydrogen storage materials. Lignin is an important supporting substance in plants, its storage capacity is second only to cellulose, it has the advantages of environmental friendly, renewable and so on. In this paper, the preparation, structure and electrochemical application of mesoporous carbon were studied by using lignin as carbon source. The results show that the electron conductivity and rate performance of mesoporous carbon can be significantly improved by loading metal oxides on the surface of mesoporous carbon. The main contents and results are as follows: 1) mesoporous carbon materials. In this paper, lignin sulfonate as carbon source, low molecular weight polyformaldehyde / glutaraldehyde as crosslinking agent, polyvinylpyrrolidone (PVP) as dispersant, brown solid synthesized by hydrothermal method as carbon precursor. Finally, mesoporous carbon materials were prepared by calcination in a tube furnace. The mesoporous carbon materials have high specific surface area, large pore volume, narrow pore size distribution, and the carbon wall of mesoporous carbon has been graphitized extensively, so it can be used as an ideal electrode material for batteries. The constant current charge-discharge test shows that the mesoporous carbon electrode has a high specific capacitance and its 1000 cyclic voltammetry results show high cycle stability. This is due to the fact that the mesoporous structure does not limit the ion transport, which makes it have excellent charge-discharge properties at high current. The mesoporous carbon materials mentioned above were used as the carrier of Ni source, and then refluxed and condensed under alkaline conditions, so that Ni could be loaded on the surface of mesoporous carbon materials and then calcined in tubular furnaces. MPCs / nio composites with porous carbon as skeleton and nio nanoparticles well dispersed were formed. The pore volume and specific surface area of mesoporous carbon decreased in varying degrees due to nio filling with carbon pores. The MPCs / nio composite was assembled into a battery. The constant current charge-discharge test showed that MPCs / nio composite had good cyclic stability with a specific capacitance of 1000 cycles. The reason is that the pseudo-capacitance of nio and the skeleton structure of mesoporous carbon materials improve the electrochemical stability of MPCs / nio composites.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;TQ127.11

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