Interconnected N/P co-doped carbon nanocage as high capacitance electrode material for energy storage devices
Yang Lei, Xiaojun He, Yuchen Wei, Honghui Bi, Feng Wei, Hongqiang Li, Changzhou Yuan, Jieshan Qiu
Abstract
Heteroatom doping carbon materials exhibit a huge application potential for energy storage devices (ESDs). Herein, interconnected N/P co-doped carbon nanocage (NP-CNC) was synthesized from pyrene molecules by using nano-MgO as template and melamine-phytic acid supramolecular aggregate as dopant coupled with KOH activation. The as-prepared NP-CNC possesses interconnected nanocages for electron transportation and abundant micropores for ion adsorption. Moreover, co-doped N/P species in NP-CNC provide active sites and additional pseudocapacitance. Consequently, NP-CNC as electrode material for symmetric supercapacitor exhibits a high gravimetric capacitance of 435 F·g−1 at 0.05 A·g−1, high volumetric capacitance of 274 F·cm−3 at 0.032 A·cm−3, and long cycle lifespan with 96.1% capacitance retention after 50,000 cycles. Furthermore, NP-CNC as cathode for zinc-ion hybrid supercapacitor delivers satisfactory energy and power densities of 130.6 Wh·kg−1 (82.3 Wh·L−1) and 14.4 kW·kg−1 (9.1 kW·L−1). This work paves a promising approach to the preparation of high capacitance NP-CNC for ESDs.