Microporous active carbon with ultrahigh surface area from Metaplexis japonica for high-performance supercapacitor

Microporous active carbon with tunable pore structure and ultrahigh specific surface area of about 2210 m(2) g(-1) was synthesized from sustainable biomass precursor Metaplexis japonica via a facile carbonization-activation method, among which, micropores with pore size ranging from 1 to 2 nm occupy 87% of the pore volume. This Metaplexis japonica-derived active carbon (MJAC) exhibited high specific capacitance (287 F g(-1) at 1.0 A g(-1)) with good rate capability and excellent cycling stability (capacitance retention of 99% after 20,000 cycles at 20 A g(-1)) in a three-electrode system. Notably, the interconnected hierarchical and open structure with a high specific surface area contributed to the wide operating voltage window of 2.2 V and high energy density of 29 W h kg(-1) at a power density of 550 W kg(-1) in a two-electrode system. Therefore, all the remarkable performance of MJAC makes it attractive for application in supercapacitor.