doi:10.16597/j.cnki.issn.1002-154x.2023.02.001
CDs/SNGA 的制备及储锂性能研究
王喜奎 李鹏 仪桂云∗ 吴元锋 张正庭 张秀秀 张玉龙 孙琦
(河南理工大学 化学化工学院,河南 焦作 454003)
Preparation and Lithium Storage Performance of CDs/SNGA
Wang Xikui； Li Peng； Yi Guiyun∗； Wu Yuanfeng； Zhang Zhengting； Zhang Xiuxiu； Zhang Yulong； Sun Qi；
(College of Chemistry and Chemical Engineering, Henan Polytechnic University, Henan Jiaozuo, 454003)
摘要:
本研究以氧化石墨烯(GO)为柔性基底,硫脲为硫氮源,碳点(CDs)为插层剂,采用水热和煅烧两步法合成碳点/硫氮共掺杂石墨烯气凝胶(CDs/SNGA) 复合材料。 通过 X 射线衍射(XRD)、紫外可见光(UV-vis) 和透射电镜 (TEM)测试分析证实 CDs 具有类石墨结构,其粒径 2~4 nm。 将其插入到石墨烯片层后,扫描电镜(SEM)显示 CDs/SNGA 复合材料孔道结构更加丰富,缓解了石墨烯片层的堆积。 电化学性能结果显示,CDs/SNGA 可逆比容量可达 229.98 mA·h·g-1(在 5 A·g-1电流密度下),明显优于硫氮共掺杂石墨烯气凝胶(SNGA,73.60 mA·h·g-1)和石墨烯气凝胶(GA,48.33 mA·h·g-1)。另外,在1 A·g-1电流密度条件下循环 300 圈后,CDs/SNGA 仍可以维持 489.3 mA·h·g-1的可逆比容量,相对于 SNGA(195.1 mA·h·g-1)和 GA(173.2 mA·h·g-1)分别提升 1.5 倍和1.8 倍。
关键词：硫脲；氧化石墨烯；碳点；气凝胶；锂离子电池；
Abstract：
In this paper, carbon dots/ sulfur-nitrogen co-doped graphene aerogel (CDs/ SNGA) composites were synthesized by a two-step hydrothermal and calcination method using graphene oxide (GO) as a flexible substrate, thiourea as a sulfur-nitrogen source and carbon dots (CDs) as an intercalator. Firstly, the results of X-ray diffraction (XRD), ultraviolet-visible (UV-vis) and Transmission electron microscope ( TEM) tests confirmed the successful synthesis of CDs with graphite-like structure and particle size of about 2 - 4 nm. After their insertion into graphene lamellae, SEM showed that the pore structure of CDs/ SNGA composites was more abundant and alleviated the accumulation of graphene lamellae. Secondly, according to the electrochemical performance results, the reversible specific capacity of CDs/ SNGA can reach about 229.98 mA·h·g-1 at 5 A·g-1 current density, which was significantly better than that of sulfur-nitrogen co-doped graphene aerogel ( SNGA, 73.60 mA · h · g-1 ) and graphene aerogel (GA, 48.33 mA·h·g-1 ). In addition, after 300 cycles at 1 A·g-1 current density, CDs/ SNGA can still maintain a reversible specific capacity of 489.3 mA·h·g-1 . Compared with SNGA (195.1 mA·h·g-1 ) and GA (173.2 mA·h·g-1 ), the increase is 1.5 times and 1.8 times respectively.
Keywords：thiourea; graphene oxide; carbon dots; aerogel; lithium-ion battery;