Green synthesis of N/B co-doped layered porous carbon with high gravimetric and volumetric capacitance for supercapacitor

Doping heteroatoms in porous carbons is an effective strategy to enhance capacitance and layered structure can increase the density of carbon, which can together improve the volumetric energy density of electrodes. In this work, N/B co-doped layered porous carbon (N x B y PC-T) is successfully designed via self-assembly of H 3 BO 3 /pectin/urea followed by one-step heat-treatment without additional activation. The obtained layered porous carbons present moderate specific surface area (119–553 cm 2 g −1 ), low pore volume and high content of N/B/O heteroatoms. The pseudocapacitive reaction mechanism of N/B/O functional groups in different electrolytes is proposed, and the N/B co-doped porous carbon presents much more extra pseudocapacitance than the single doped ones in alkaline electrolyte . The unique layered structure, the high density and N/B co-doping effectually enhance the overall specific and volumetric capacitance. The as-obtained N x B y PCs-T exhibit the specific gravimetric capacitance of at most 358 F g −1 for N 2 B 10 PC-800 and the high volumetric capacitance of 577 F cm −3 for N 2 B 10 PC-900. Furthermore, N 2 B 10 PC-900 symmetrical supercapacitor displays a high volumetric energy density of 12.6 mW h cm −3 at a power density of 810 mW cm −3 . •The N/B co-doped layered porous carbon is successfully designed. •The porous carbon present moderate specific surface area and high heteroatoms. •The co-doped porous carbon presents remarkable pseudocapacitive. • The co-doped layered porous carbon possesses excellent volumetric capacitance.