High performance supercapacitor prepared from hollow mesoporous carbon capsules with hierarchical nanoarchitecture

Hollow core mesoporous shell carbon (HCMSC) capsules are prepared by nano-casting method which involves surfactant-assisted synthesis of silica spheres with mesoporous shell as template and impregnation of carbon precursor into mesoporous shell of the silica, followed by carbonization and silica template removal. The resulting HCMSC capsules possess 3D-interconnected nanoarchitecture with unique hierarchical meso/macro-porosity along with high surface area and large mesopore volume. The HCMSC capsules are tested for electrochemical double layer capacitor in a standard two electrode flat cell using non-aqueous electrolyte. The specific capacitance measured by galvanostatic charge-discharge at 0.3 A g(-1) current density is found to be 162 F g(-1), which is among the highest values reported so far for mesoporous carbon materials in a practical two electrode symmetric system using organic electrolyte. The cyclic performance tested at high current density of 1.0 A g(-1) is found to retain 88% of initial capacity up to 2000 charge-discharge cycles. High capacitance performance of the HCMSC is attributed to the well-developed hierarchical 3D open network of macropores and interstitial void open to mesopores in the mesoporous shell, which not only facilitate fast charge transfer, but also facile electrolyte movement to access the active sites. (C) 2013 Elsevier B.V. All rights reserved.