煤基中间相半焦制备及其用于超级电容器电极材料研究

发布时间：2018-05-30 18:34

  本文选题：密中质组 + 中间相半焦　； 参考：《中国矿业大学》2017年硕士论文

【摘要】：以煤全组分族分离所得的密中质组(中间相的来源物质,即源质)为原料,制备了中间相半焦,考察了炭化温度、恒温时间、升温速率、原料成型压力对源质生成中间相半焦的影响及中间相半焦的生成过程,分析了中间相半焦的官能团结构与微晶结构的演化进程,探讨了由源质生成中间相小球体进而形成中间相半焦的机理。用KOH活化法制备了活性中间相半焦,对其用于超级电容器电极材料的电化学性能进行了表征。结果表明:升高温度加剧了热解和缩聚反应,有利于中间相的生成以及向流线型演化,而温度较高加快了气体逸出,不利于中间相的发展;恒温时间的延长加深了反应进程,有利于中间相半焦向流线型结构演变;升温速率在4℃/min时,中间相半焦的光学形貌呈现大面积广域流线型;原料成型压力主要通过改变源质的颗粒间隙影响中间相的发展,增加压力会影响反应热效率、小分子逸出以及惰性气流的引导作用,不利于中间相的有序化发展。生成中间相小球体并向流线型中间相半焦转化的较佳条件为450℃、4℃/min、散装进料。在此条件下,随着恒温时间的延长,中间相的演化进程为中间相小球体→小广域型→中等流线型→粗流线型→广域流线型(粗型)→广域流线型(细型)。其机理为:源质中组成5 nm纳粒的网络大分子平面化,平面分子聚集并相互堆叠成层积体,分子层积体相互穿插形成基核,基核融并形成中间相小球体,小球体相互融并长大,球体解体并固化形成小广域型中间相半焦,在热缩聚及气流剪切作用下半焦向流线型演变。以不同光学形貌的中间相半焦活化而制备的活性中间相半焦的比表面积均达到2000 m2/g,微孔容积达到1 cm3/g,以广域流线型(粗型)中间相半焦制备的活性中间相半焦孔结构参数最好,因为此形貌下活性中间相半焦的片层结构有利于KOH逐层活化,同时有序性适中使得KOH与内部C原子反应的活化能较低,此时比电容量达到225.90 F/g。
[Abstract]:The mesophase semi-char was prepared from the dense mesophase (mesophase source material, I. e., source material) obtained from the separation of whole coal components. The carbonization temperature, constant temperature time and heating rate were investigated. The influence of raw material forming pressure on the formation of mesophase semi-coke and the formation process of mesophase semi-coke were analyzed. The evolution process of functional group structure and microcrystalline structure of mesophase semi-coke was analyzed. The mechanism of the formation of mesophase semi-coke from mesophase is discussed. Active mesophase semi-char was prepared by KOH activation method and its electrochemical properties for supercapacitor electrode materials were characterized. The results show that the increase of temperature intensifies the pyrolysis and Polycondensation reaction, which is conducive to the formation of mesophase and the evolution to streamline, while the higher temperature accelerates the gas escape, which is not conducive to the development of mesophase, and the prolongation of the constant temperature time deepens the reaction process. The optical morphology of mesophase semi-coke shows a wide area streamline shape at the heating rate of 4 鈩，

本文编号：1956344