Activated Microporous Carbon Nanospheres for Use in Supercapacitors

Microporous carbon spheres (MCSs) fabricated using the extended Stöber method have unique features, such as a narrow particle size distribution and a variety of applications. Here, we report the synthesis of nanosized MCSs using a modified version of the extended Stöber method at an ambient condition, which is a simple, quick, and scalable process. The activation of nanosized MCSs using CO2 is conducted to increase the surface area of MCSs. The activated microporous carbon nanospheres (AMCNSs) have a specific surface area of 3259 m2/g and a mean diameter of about 52 nm. To the best of our knowledge, this is the smallest reported particle size for carbon spheres with a very high specific surface area. In addition, AMCNSs have a hierarchical structure, which is beneficial for mass transport. The AMCNSs are evaluated for application in supercapacitors. The results show that a capacitance of 225 F/g at a current density of 0.5 A/g in a 6 M KOH aqueous electrolyte can be achieved, indicating that AMCNSs have a potential for supercapacitor applications.