Pseudocapacitance of zeolite-templated carbon in organic electrolytes

Carbon and graphene-based materials often show some amount of pseudocapacitance due to their oxygen-functional groups. However, such pseudocapacitance is generally negligible in organic electrolytes and has not attracted much attention. In this work, we report a large pseudocapacitance of zeolite-templated carbon (ZTC) based on the oxygen-functional groups in 1 M tetraethylammonium tetrafluoroborate dissolved in propylene carbonate (Et4NBF4/PC). Due to its significant amount of active edge sites, a large amount of redox-active oxygen functional groups are introduced into ZTC, and ZTC shows a high specific capacitance (330 F g−1). Experimental results suggest that the pseudocapacitance could be based on the formation of anion and cation radicals of quinones and ethers, respectively. Moreover, ZTC shows pseudocapacitance also in 1 M lithium hexafluorophosphate dissolved with a mixture of ethylene carbonate and diethyl carbonate (LiPF6/EC+DEC) which is used for lithium-ion batteries and lithium-ion capacitors.

This research was partially supported by the Strategic International Cooperative Program, Japan Science and Technology Agency (T.K.); a Grant-in-Aid for Scientific Research (A), 15H01999 (T.K.); a Grant-in-Aid for Scientific Research (B), 26286020 (H.N.); and the Spanish MINECO, FEDER funds (Project MAT2013-42007-P and PRI-PIBJP-2011-0766). This research was supported also by Nano-Macro Materials, Devices and System Research Alliance and by Network Joint Research Center for Materials and Devices.