球形石墨@碳化硅衍生碳的制备及其电化学性能的研究

发布时间：2018-02-09 19:26

本文关键词： 碳化硅衍生碳球形石墨比表面积孔径分布电化学性能　出处：《武汉科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：为满足储能领域对材料兼具高能量密度和高功率密度的需求，本论文旨在将具有特殊孔隙结构的碳化物衍生碳与具有高导电性和高能量存储密度的石墨类材料相复合的方式，制备得到一种具有核壳结构的双功能复合炭材料。以两种球形石墨炭材料，即石墨化中间相炭微球（GMCMB）和球形天然石墨（NG）为碳源，与硅粉（Si）高温固相反应生成GMCMB@SiC和NG@SiC前躯体，然后经氯气刻蚀制备得到石墨化中间相炭微球@碳化硅衍生碳（GMCMB@SiC-CDCs）和球形天然石墨@碳化硅衍生碳（NG@SiC-CDCs）复合炭材料。通过对复合材料的组成、结构、形貌、孔结构、比表面积以及电化学性能的表征与分析，初步探讨了其储能机理。主要的研究结果如下：（1）采用固相法与氯气刻蚀相结合的方法可成功制备GMCMB@SiC-CDCs和NG@SiC-CDCs复合材料，该材料具有典型的核@壳结构，即分别以GMCMB和NG为核，以具有＜1nm的微孔的SiC-CDCs为壳。（2）通过控制碳源与硅的摩尔比（C/Si）可以有效调控SiC-CDCs壳的厚度和GMCMB/NG核的尺寸，，并在较大的范围内调节复合材料的比表面积和孔体积；C/Si摩尔比越小，SiC-CDCs在复合材料中的含量越高，对应的比表面积和孔体积越高。（3）选择适宜的C/Si摩尔比（即适宜的衍生碳和球形石墨相对含量）可以有效提高锂离子电池负极的可逆容量，同时表现出比单一GMCMB和NG更好的倍率性能和更高的容量保持率。（4）GMCMB@SiC-CDCs和NG@SiC-CDCs复合材料用作超级电容器电极材料，均表现出良好的电容性能，随着C/Si摩尔比的减小即SiC-CDCs含量升高，复合材料的比电容和能量密度都增大，且可实现大电流充放电。
[Abstract]:In order to meet the demand of high energy density and high power density for materials in the energy storage area , a dual - functional composite carbon material with core - shell structure is prepared by combining the carbide - derived carbon with special pore structure with the graphite material with high conductivity and high energy storage density . ( 1 ) GMCMB @ SiC - CDCs and NG @ SiC - CDCs composites can be successfully prepared by the combination of solid - phase method and chlorine gas etching . ( 2 ) By controlling the molar ratio of carbon source to silicon ( C / Si ) , the thickness of the SiC - CDCs shell and the size of the GMCMB / NG core can be effectively controlled , and the specific surface area and pore volume of the composite material can be adjusted in a larger range ; the smaller the C / Si molar ratio , the higher the content of the SiC - CDCs in the composite material , and the higher the specific surface area and the pore volume . ( 3 ) Choosing the proper C / Si molar ratio ( i.e . , the relative content of the appropriate derived carbon and spherical graphite ) can effectively improve the reversible capacity of the negative electrode of the lithium ion battery , and exhibit better multiplying power performance and higher capacity retention rate than the single GMCMB and NG . ( 4 ) GMCMB @ SiC - CDCs and NG @ SiC - CDCs composite materials are used as the electrode materials of the super capacitor , which exhibit good capacitive performance . As the C / Si molar ratio decreases , the SiC - CDCs content is increased , the specific capacitance and energy density of the composite material are increased , and the large current charging and discharging can be realized .

【学位授予单位】：武汉科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11

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