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OALib Journal期刊
ISSN: 2333-9721
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-  2020 


DOI: 10.3866/PKU.WHXB201903055

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Abstract:

植物基多孔炭具有发达的孔结构、大的表面积、较为成熟的制备工艺、丰富的来源、低廉的价格,是目前商业应用范围最广的超级电容器电极材料。然而在实际应用中仍然存在着质量/体积比容量较低、倍率性能差等问题。本文针对先进电容器件的高能量密度、优异功率性能的要求,首先介绍了近年来发展的植物基多孔炭的制备方法,讨论了植物前驱体的组成和结构对其产物结构的影响以及与其电化学性能之间的构效关系,特别总结了近年来植物基超大比表面积多孔炭、中孔炭、层次化多孔炭的制备方法和电容储能性能。针对大比表面积多孔炭用于超级电容器时的体积性能不佳这一关键问题,本文还总结了提高植物基多孔炭体积电化学性能的方法。最后,对植物基多孔电极材料存在的问题进行了分析与总结,并展望了其研究前景。
Supercapacitors have been widely used in various fields because of their high power density, long cycle life, and cost-effectiveness. Plant-based porous carbon continues to be the most suitable alternative for manufacturing the commercial electrode materials of supercapacitors because of its good electrochemical performance, simple preparation process, high availability, and low cost. Although plant-based porous carbon prepared using physical activation has been widely used in commercial supercapacitors, its performance is severely restricted because of its low value of specific surface area and highly microporous structure. With a view to achieving high values of specific gravimetric/volumetric capacitances and outstanding rate performance in supercapacitors, this review summarizes the recently developed methods for preparing plant-based ultrahigh specific surface area porous carbon materials, mesoporous carbon materials, hierarchical porous carbon materials, and nitrogen-doped porous carbon materials. The factors affecting the electrochemical performance of plant-based porous carbon are also discussed. We also summarize some novel strategies to improve the volumetric electrochemical performance of plant-based porous carbon materials, such as preparing dense and porous carbon materials, performing heteroatom doping, and combining the carbon with pseudocapacitive materials (conductive polymers or metal oxides). Finally, the challenges and perspectives of using plant-based porous carbon in supercapacitors are also proposed. In brief, when used as the electrode material for supercapacitors, the ultrahigh surface area porous carbon prepared by KOH activation shows high value of specific capacitance at low current densities. However, the tortuous and deep micropores in the plant-based porous carbon result in its sluggish ion-transport kinetics and high value of equivalent series resistance, which, in turn, result in poor rate performance. To improve the rate performance, tremendous efforts have been made to introduce mesopores in the carbon as ion-transport channels. However, this strategy usually involves the coalescence of a large number of micropores, resulting in the reduced surface area as well as energy storage ability of the

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