Electrochemical supercapacitor slectrodes from sponge-like graphene nanoarchitectures with ultrahigh power density
We employed a microwave synthesis process of cobalt phthalocyanine molecules templated by acid-functionalized multiwalled carbon nanotubes to create three-dimensional sponge-like graphene nanoarchitectures suited for ionic liquid-based electrochemical capacitor electrodes that operate at very high scan rates. The sequential “bottom-up” molecular synthesis and subsequent carbonization process took less than 20 min to complete. The 3D nanoarchitectures are able to deliver an energy density of 7.1 W·h kg–1 even at an extra high power density of 48 000 W kg–1. In addition, the ionic liquid supercapacitor based on this material works very well at room temperature due to its fully opened structures, which is ideal for the high-power energy application requiring more tolerance to temperature variation. Moreover, the structures are stable in both ionic liquids and 1 M H2SO4, retaining 90 and 98% capacitance after 10 000 cycles, respectively.
Z Xu, Z Li, CMB Holt, X Tan, H Wang, B Shalchi-Amirkhiz, T Stephenson and D Mitlin
Journal of Physical Chemistry Letters, 3 (2012) 2928-2933