Mesoporous activated carbon materials with ultrahigh mesopore volume and effective specific surface area for high performance supercapacitors

High specific surface area (SSA), especially effective specific surface area (E-SSA) of the active electrode materials is required for high performance supercapacitors. In this work, such materials (e.g. AC-KOH) were obtained using a scalable industrial method from biomass waste material, with controlling the pore size distribution and mesopores as the major contribution. Thus, an electrode material, with ultrahigh mesopore volume of 1.85 cm3 g−1, E-SSA up to 1771 m2 g−1 for organic electrolyte ion (TEA+) and taking 55% of the total SSA of 3237 m2 g−1 with an excellent conductivity of 33 S m−1, was obtained. With these outstanding properties, the materials demonstrate excellent double-layer capacitance with remarkable rate performance and good cycling stability. The material delivers capacitance up to 222, 202 and 188 F g−1 at current density of 1 A g−1 in aqueous, organic and ionic liquid electrolyte system, respectively. Meanwhile, it exhibits a high energy density of 80 W h kg−1 in ionic liquid electrolyte at a power density of 870 W kg−1. Furthermore, these materials can be produced in large scale from various biomass materials, and thus could be an excellent choice of the high performance materials required in the increasing important supercapacitor industry.

An electrode material (AC-KOH) with ultrahigh effective specific surface area up to 1771 m2 g−1 for organic electrolyte ion (TEA+), taking 55% of the total specific surface area of 3237 m2 g−1, mesopore volume of 1.85 cm3 g−1 with 81.5% proportion of the total pore volume of 2.27 cm3 g−1 and excellent conductivity of 33 S m−1 was obtained. AC-KOH based supercapacitor delivers capacitance up to 222, 202 and 188 F g−1 at current density of 1 A g−1 in aqueous, organic and ionic liquid electrolyte system, respectively. Meanwhile it exhibits high energy density of 80 W h kg−1 in ionic liquid electrolyte at power density of 870 W kg−1, superior than that of commercial activated carbon YP50. AC-KOH based coin-type supercapacitor could lighten a red LED and make it light up for ∼30 min.255