Hierarchical Design for Fabricating Cost-Effective High Performance Supercapacitors

作者:Kim Nam Dong*; Buchholz D Bruce; Casillas Gilberto; Jose Yacaman Miguel; Chang Robert P H
来源:Advanced Functional Materials, 2014, 24(26): 4186-4194.
DOI:10.1002/adfm.201304130

摘要

The salient feature of a supercapacitor is its ability to deliver much higher power density than a battery. A hierarchical design and a cost-effective approach to fabricate high performance supercapacitors using functional carbon nano-particles is reported. A special arc synthesis method is used to produce amorphous/crystalline composite with nitrogen and boron co-doped high charge density carbon nanoparticles. Upon etch removal of the amorphous phase in the composite nanoparticle, a crystalline carbon framework emerges, consisting of a mixture of nano-graphitic sheets mostly in the middle and single nanohorns distributed around the surface of the nanoparticle. These nanoparticles have large internal/external surfaces with subnano channels and sharp nano-tips for high speed charge transport and local charge accumulation. To deliver high power density, the internal resistance of the device is reduced by assembling the nanoparticles via electro-spraying and compacting them into dense films (without any binder) under 700 MPa of pressure before supercapacitor assembly. Taken together, the hierarchical processed supercapacitor has a very high (compared to literature values) power density of nearly 4.5 kW cm(-3) and a respectable energy density of 2.45 mWh cm(-3). Combining these carbon nanoparticles with large area spraying coating, it can lead to a cost-effective production of high performance supercapacitors.