自支撑氮掺杂石墨烯纸柔性电极的制备及其储锂性能的研究

以氧化石墨烯(GO)为原料,尿素为氮掺杂剂,采用固/气界面水热反应的方式,即在反应釜内将GO抽滤得到的氧化石墨烯纸(GOP)与尿素分解产生的氨蒸气相互作用,成功制备出自支撑氮掺杂石墨烯纸(NGP)。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、拉曼光谱(RS)、X射线光电子能谱(XPS)和电化学测试对样品进行形貌结构及电化学性能的表征。测试结果表明:水热条件下尿素能有效地实现氧化石墨烯纸的氮掺杂,氮掺杂量为7.89%;氮掺杂石墨烯纸在100mA/g和500mA/g的电流密度下,充放电循环100周之后,放电比容量可分别保持在288mAh/g和190mAh/g。采用改进的固/气界面水热反应法制备的氮掺杂石墨烯纸较未掺杂石墨烯纸可逆比容量提高了近2.5倍,具有良好的循环稳定性,可为制备高性能的柔性锂离子电池负极材料提供新方法。

Preparation of Free-standing Flexible N-doped Graphene Paper Electrode and the Study of Its Lithium Storage Properties

Free-standing N-doped graphene paper was prepared by solid/vapor interface hydrothermal reduction method using graphene oxide(GO)as the raw material and urea as the nitrogen dopant. Herein, the solid/vapor interface reaction is utilized, in which the graphene oxide paper obtained via vacuum filtration reacts with ammonia vapor generated from the decomposition of urea. X-ray diffraction(XRD), scanning electron microscopy(SEM), Raman spectroscopy(RS),X-ray photoelectron spectroscopy(XPS)and electrochemical measurements are employed to characterize the morphology and electrochemical performance of the prepared pro-ducts. The results show that nitrogen can be efficiently doped into oxidized graphene paper with a doping content of ca. 7.89% under the hydrothermal conditions. The specific discharge capacity of nitrogen-doped graphene paper can be maintained with 288 mAh/g and 190 mAh/g after 100 cycles at a current density of 100 mA/g and 500 mA/g, respectively. Thus prepared nitrogen-doped graphene paper delivers ca. 2.5 times higher reversible specific capacity than undoped graphene paper, and exhibits excellent cycling performance, which provides new opportunities for the preparation of high performance flexible lithium ion battery anode material.