Abstract
To resolve the pore-associated bottleneck problem observed in the electrode materials used for ultracapacitors, which inhibits the transport of the electrolyte ions, we designed hierarchically structured activated carbon (HAC) by synthesizing a mesoporous silica template/carbon composite and chemically activating it to simultaneously remove the silica template and increase the pore volume. The resulting HAC had a well-designed, unique porous structure, which allowed for large interfaces for efficient electric double-layer formation. Given the unique characteristics of the HAC, we believe that the developed synthesis strategy provides important insights into the design and fabrication of hierarchical carbon nanostructures. The HAC, which had a specific surface area of 1,957 m2 g−1, exhibited an extremely high specific capacitance of 157 F g−1 (95 F cc−1), as well as a high rate capability. This indicated that it had superior energy storage capability and was thus suitable for use in advanced ultracapacitors.
Highlights
To resolve the pore-associated bottleneck problem observed in the electrode materials used for ultracapacitors, which inhibits the transport of the electrolyte ions, we designed hierarchically structured activated carbon (HAC) by synthesizing a mesoporous silica template/carbon composite and chemically activating it to simultaneously remove the silica template and increase the pore volume
Given the unique characteristics of the HAC, we believe that the developed synthesis strategy provides important insights into the design and fabrication of hierarchical carbon nanostructures
Mesoporous carbon materials are used as electrode materials for UCs, owing to their narrow pore size distribution, which allows for rapid ion diffusion and mass transfer[9,10,11]
Summary
To resolve the pore-associated bottleneck problem observed in the electrode materials used for ultracapacitors, which inhibits the transport of the electrolyte ions, we designed hierarchically structured activated carbon (HAC) by synthesizing a mesoporous silica template/carbon composite and chemically activating it to simultaneously remove the silica template and increase the pore volume. The use of mesostructured silicates as a hard template material allows for the synthesis of well-ordered porous carbon materials with tailored structural characteristics, including controlled pore size, pore volume, particle size, and morphology[12] Such mesoporous carbon materials usually exhibit better electrochemical performance than those of AC at high current densities, because of the presence of mesopore channels and interconnections, which provide suitable paths for the penetration and transportation of electrolyte ions. The excellent properties of this material were attributable to the presence of three-dimensional hierarchical carbon, which was both porous and graphitic in nature They determined that both the surface area and the porosity of a material determine its suitability for use as an electrode material in UCs and that the presence of both macropores and mesopores is a prerequisite for the fast transport of electrolytes to the smaller mesopores and micropores. Though significant progress has been made in the design of porous carbon materials, further advances are needed for the rational design of materials with the desired porous characteristics
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
