Porous mesocarbon microbeads with graphitic shells: Constructing a high-rate, high-capacity cathode for hybrid supercapacitor

Abstract

Li4 Ti5 O12/activated carbon hybrid supercapacitor can combine the advantages of both lithium-ion battery and supercapacitor, which may meet the requirements for developing high-performance hybrid electric vehicles. Here we proposed a novel core-shell porous graphitic carbon (PGC) to replace conventional activated carbon for achieving excellent cell performance. In this PGC structure made from mesocarbon microbead (MCMB), the inner core is composed of porous amorphous carbon, while the outer shell is graphitic carbon. The abundant porosity and the high surface area not only offer sufficient reaction sites to store electrical charge physically, but also can accelerate the liquid electrolyte to penetrate the electrode and the ions to reach the reacting sites. Meanwhile, the outer graphitic shells of the porous carbon microbeads contribute to a conductive network which will remarkably facilitate the electron transportation, and thus can be used to construct a high-rate, high-capacity cathode for hybrid supercapacitor, especially at high current densities. © 2013 Macmillan Publishers Limited.