Mesoporous tubular graphene electrode for high performance supercapacitor

We report the fabrication of mesoporous tubular graphene (MTG) by a chemical vapor deposition method using MgO@ZnO core-shell structure as the template. The unique bi-directional ions transfer in unstack graphene layers and high mesopore ratio of MTGs allows capacitance reach 15 μF/cm² at 0.5 A/g, and 11 μF/cm² at 10 A/g, which is closer to theoretical value (21 μF/cm²) than SWCNTs and DWCNTs at either low or high rate. Meanwhile, MTGs exhibited good structural stability, high surface area (701 m²/g), high conductivity (30 S/cm) and low oxygen ratio (0.7 atom%), allowing excellent SC performance. The 4 V EDLC using MTGs and EMIMBF₄ electrolyte exhibited high energy density in wide range of high power density and excellent cycling stability, showing strong potential in EDLC and other electrochemical energy storage systems, in addition, showing significant factor of ion transfer distance for high performance SCs especially operating at high voltage using ionic liquid electrolyte.