具有高体积比电容的富氮褶皱石墨烯的制备

Supercapacitors based on nitrogen-enriched crumpled graphene with a high volumetric capacitance and high-mass-loading per area of the electrode

  • 摘要: 目前超级电容器较低的体积容量以及高负载量时缓慢的扩散动力学,阻碍了其能量密度和功率密度的进一步提高。本文利用气溶胶法处理氧化石墨烯和尿素溶液制备了褶皱尿素/氧化石墨烯,最后通过600 °C快速高温分解50 s得到了含氮量高达11.38% 的皱褶石墨烯。将600oC快速热解制备的皱褶石墨烯作为超级电容器电极材料时,体积比电容高达384.0 F cm−3,并且离子可以快速转移,即使在高电流密度(10 A g−1)和高负载量(每个电极 21.00 mg)情况下,样品仍能保持较高的比容量。本文提出样品吡咯、酰亚胺、内酰胺或其他类型的吡啶类氮和高比表面积是提高电容的关键因素,而褶皱结构能够加快离子转移速度。

     

    Abstract: The low volumetric capacity and sluggish diffusion of ions at high mass loadings of active materials per area limit any improvement of the energy and power densities of supercapacitors. A mixture of graphene oxide (GO) and urea in water was treated by an ultrasonic atomizer to form aerosol droplets, which were dried to obtain crumpled GO/urea particles. Crumpled graphene with a nitrogen content of 11.38% was obtained by the thermal shocking of these particles at 600 °C for 50 s. A volumetric capacitance of 384.0 F cm−3 was achieved when the crumpled graphene was used as supercapacitor electrodes. Even at a high current density (10 A g−1) and a high loading (74.3 mg/cm2 electrode), the specific capacitance retention still remained high. It is proposed that N-doping in the forms of pyrrole, imide, lactam and other types of pyridine-like nitrogen, and high surface area of the sample were key factors in improving the capacitance. The crumpled structure provided high mass transfer and high accessibility of ions to the active surface.

     

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