高浓度石墨烯浆料的制备与应用研究

PREPARATION AND APPLICATION OF HIGHLY CONCENTRATED GRAPHENE SLURRY

卫晓婷

11930271

硕士

材料工程

徐政和(Zhenghe Xu)

2021-05-15

2021-06-23

南方科技大学

深圳

石墨烯自被发现以来，就因其优异的物理化学性能深受众多科学家和研究学者的追捧，然而石墨烯在应用过程中最亟待解决的问题就是它在水相中的分散性。虽然目前已进行了各种分散方法的研究，但分散技术困难以及分散体系复杂等因素仍然制约着石墨烯水性浆料（悬浮液）的大规模制备与应用。 本论文利用表面官能团改性技术在石墨烯边缘加载羧基和氨基对石墨烯进行改性研究，通过X射线光电子能谱定量分析发现改性后的石墨烯表面的含氧量为3.85 wt.%，含氮量为0.85 wt.%，并通过红外光谱分析检测到C=O和C-N键的存在，表明成功地在石墨烯边缘上同时加载了负电基团和正电基团。以氧化石墨烯为载体，通过调节pH所形成的改性石墨烯水性分散液最高固体浓度可达500 mg/mL，该改性石墨烯分散液可作为分散剂分散本征石墨烯，最终得到360 mg/mL的高浓度水性石墨烯浆料（悬浮液）。扫描电子显微镜形貌分析发现用pH = 10的浆料分散石墨烯，最终得到的结构类似于蜂窝状，该结构在用于锂离子电池导电剂的过程中可与活性物质硅进行大面积的结合，最终形成导电网络。通过电化学性能测试发现，经过150次循环后，锂离子电池仍具有1509.6 mAh/g的放电比容量，并具有优异的倍率性能。

Since its first discovery, graphene has been sought after as preferred materials by many scientists and researchers for its excellent physicochemical properties. However the most urgent problem to be resolved in the application of graphene is its dispersion. Although scientists have carried out extensive researches to search for various dispersion methods, the difficulty of dispersion technology and the complexity of the dispersion system restrict the largescale preparation and application of graphene dispersions (slurry). This study uses chemical-mechanical surface engineering method to introduce carboxyl and amido groups on the surface of graphene. Quantitative analysis by X-ray photoelectron spectroscopy (XPS) revealed 3.85 wt.% oxygen and 0.85 wt.% nitrogen on the modified graphene surfaces. The presence of C=O and C-N bonds was detected by infrared spectroscopy, indicating successful loading of both negatively charged and positively charged groups on the graphene surfaces. Using graphene oxide as a carrier, the suspension of 500 mg/mL modified graphene was achieved by adjusting the pH of suspension. The suspension prepared as such by the modified graphene was shown to be an excellent dispersing agent to disperse graphene. With its dispersant, high-concentration graphene aqueous dispersion (slurry) of 360 mg/mL was obtained Morphology analysis by scanning electron microscope revealed honeycomb structure of graphene in such high concentration aqueous dispersion of pH = 10. After being applied to a conductive agent in a lithium-ion battery, this unique structure could host the active silicon nanoparticles in a large area, forming a conductive network. The electrochemical performance test showed a specific discharge capacity of 1509.6 mAh/g and an excellent rate performance even after the lithium-ion battery underwent 150 cycles.

高浓度石墨烯浆料 机械-化学表面改性 改性石墨烯/氧化石墨烯分散剂 水系石墨烯浆料 锂离子电池

high concentration graphene chemical- mechanical surface engineering graphene oxide/modified graphene dispersant water-based graphene slurry lithium-ion battery

中文

独立培养

南方科技大学

卫晓婷. 高浓度石墨烯浆料的制备与应用研究[D]. 深圳. 南方科技大学,2021.