Nitrogen-doped worm-like graphitized hierarchical porous carbon designed for enhancing area-normalized capacitance of electrical double layer supercapacitors

• Published in: Carbon (New York) Vol. 117; pp. 163 - 173
• Main Authors: Liu, Zheng, Xiao, Kuikui, Guo, Hui, Ning, Xiaohua, Hu, Aiping, Tang, Qunli, Fan, Binbin, Zhu, Yanfei, Chen, Xiaohua
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.06.2017; Elsevier BV
• Subjects: Agglomeration; Capacitance; Carbon; Colloids; Commercialization; Constraining; Density of states; Doping; Embossing; Graphitization; Iron sulfates; Nitrogen; Supercapacitors
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2017.02.087

Electrical double layer supercapacitors (EDLC) have an upper limit for their area-normalized capacitance (CA) and lead to a bottleneck that impede the commercialization of high-energy-density supercapacitor devices. Quantum capacitance (CQ) in series with electrical double layer capacitance (CEDL) has been demonstrated to be a tremendous obstacle for enhancing the CA of EDLC. Nitrogen doping can up-shift the Fermi-level and graphitization can improve the density of states (DOS), both of which can significantly mitigate the limiting influence of CQ. Here, a facile approach is developed for synthesizing an ideal carbon-based EDLC electrode material by simply adding ferrous sulfate heptahydrate (FSH) into the polymer when colloid aggregation. The morphology, porous structure, graphitization degree, doped N content and the types of the doped N of the samples can be easily tuned through changing the FSH ratio. The optimized nitrogen doped worm-like hierarchical porous carbon with graphitized porous carbon embossment (NWHC-GE) exhibits an exceptionally high CA (24.6 μF cm−2 at 1 A g−1 and 18.5 μF cm−2 at 100 A g−1). This demonstrates a way to enhance the CA and provides a potential strategy for breaking through the limiting specific capacitance of carbon-based materials. [Display omitted]