Rationally tuning ratio of micro- to meso-pores of biomass-derived ultrathin carbon sheets toward supercapacitors with high energy and high power density

The present work provides a novel one-step synthesis for nitrogen-doped activated carbon. The excellent performance of the N-doped AC allows its further application in a hybrid-type supercapacitor, which utilizes a combination of the capacitor electrode and a Li-ion battery anode. Nitrogen-doped activated carbons (NACs) were prepared through a one-step process. The obtained NACs show high surface areas of up to 2900 m 2 g −1 with a moderate N content of up to 4 wt%. Electrochemical evaluation of the NACs shows a high specific capacity of 129 mA h g −1 (185 F g −1 ) in an organic electrolyte at a current density of 0.4 A g −1 , as well as excellent rate capability and cycling stability. The hybrid-type supercapacitor assembled using the NACs and a Si/C electrode exhibits a high material level energy density of 230 W h kg −1 at 1747 W kg −1 . The hybrid device achieved 76.3% capacity retention after 8000 cycles tested at 1.6 A g −1 . Show more