煤基富氧多孔炭纳米片的制备及其超级电容器性能

Fabrication of coal-based oxygen-rich porous carbon nanosheets for high-performance supercapacitors

  • 摘要: 多孔炭电极的表面改性与优化是实现超级电容器优异性能的关键。本文以煤化学工业的固体副产物为碳源,利用二维层状双氢氧化物(MgAl-LDH)的刚性约束作用耦合KOH活化工艺成功制备了二维富氧多孔炭纳米材料(OPCN)。系统研究了炭化温度对OPCN样品微观结构和表面特性的影响,通过SEM、TEM、氮气吸脱附测试以及元素分析等表征手段对炭材料的结构/组成和表面特性进行分析表明,经700 °C炭化获得的炭材料样品(OPCN-700)具有较高的氧质量分数(24.4%)和大的比表面积(2 388 m2 g−1),并表现出良好的润湿性。同时,OPCN-700样品丰富的微孔和二维纳米片结构为电解质离子提供了有效的储存和传输途径。作为超级电容器的电极材料,在电流密度为0.5 A g−1时,其比电容高达382 F g−1,并呈现出优异的倍率性能和循环稳定性。该技术策略为富氧原子掺杂二维多孔炭材料的可控制备与水系储能器件的设计构建提供了新思路。

     

    Abstract: The modification and optimization of porous carbon electrodes is key to achieving high-performance supercapacitors. Oxygen-rich porous carbon nanosheets (OPCNs) with a two-dimensional (2D) structure produced from the solid by-products of the coal industry were prepared by taking advantage of the rigid confinement of 2D MgAl-layered double hydroxides (MgAl-LDH) combined with KOH activation. The influence of carbonization temperature on the microstructure and surface properties of the OPCNs was investigated. The surface morphologies/compositions and surface textures of the prepared OPCNs were observed and analyzed by SEM, TEM, N2 adsorption and desorption, elemental analysis, etc. The optimized carbon sample activated at 700 °C (OPCN-700) had a high oxygen content of 24.4 wt%, a large specific surface area of 2 388 m2 g−1, and good wettability. In addition, the abundant micropores and 2D nanosheet structure of OPCN-700 provide efficient storage and transport for electrolyte ions. Because of this, when used as the electrode for a supercapacitor it has a high specific capacitance of 382 F g−1 at 0.5 A g−1, an excellent rate performance and cycling stability.

     

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