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Download fileTemplate-Free, Self-Doped Approach to Porous Carbon Spheres with High N/O Contents for High-Performance Supercapacitors
journal contribution
posted on 2019-03-04, 00:00 authored by Danfeng Xue, Dazhang Zhu, Wei Xiong, Tongcheng Cao, Zhiwei Wang, Yaokang Lv, Liangchun Li, Mingxian Liu, Lihua GanA template-free
and self-doping approach is developed for fabricating
N,O-enriched porous carbon spheres (PCSs) via direct carbonization/activation
of melamine-glyoxal polymer. The interconnected spherical morphology
of PCSs generates stacking porosities as ion reservoirs for rapid
ion diffusion and affords conductive networks to shorten the transport
lengths for electron transfer. Besides, PCSs exhibit a large surface
area (1302 m2 g–1), ample ultramicropores
(0.54 nm), and developed supermicro- and mesopores. This unique pore
architecture provides optimized ion-accessible pore size to enhance
double layer capacitance, and serves as ion-highways for rapid diffusion
of electrolyte ions. Furthermore, high N/O elements (7.97/10.16 wt
%) incorporated into PCSs improve surface wettability and supply additional
pseudocapacitance. Therefore, the resultant PCS electrodes exhibit
superior electrochemical performances, such as a high specific capacitance
up to 344 F g–1 at 1.0 A g–1,
remarkable rate capability, and long-term stability in a three-electrode.
Notably, the PCS-based supercapacitor exhibits an impressive energy
density of 33.37 Wh kg–1 and power density of 9000
W kg–1 in Na2SO4 electrolyte.
This result provides a simple and efficient fabrication of PCSs for
high-performance supercapacitors.
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High-Performance SupercapacitorsPorous Carbon Sphereselectrochemical performancesmelamine-glyoxal polymerconductive networksself-doping approachrate capabilityion reservoirselectron transferelectrolyte ionscarbon spheresPCS electrodes exhibitenergy densityoptimized ion-accessible pore sizepore architecturesurface wettabilitypower densitySelf-Doped Approachion diffusionNa 24 electrolytetransport lengthsPCSs exhibitlayer capacitancePCS-based supercapacitor exhibits