MgO template-assisted synthesis of hierarchical porous carbon with high content heteroatoms for supercapacitor

Traditional porous carbon obtained by potassium hydroxide activation are facing with complex preparation process, low heteroatoms content and sluggish ion-transport kinetics caused by their amorphous microporous structure. Herein, we develop a facile method to prepare heteroatom-doped hierarchical porous carbon (HPC) using magnesium oxide as template and polyacrylamide as raw material without any activation. MgO and polyacrylamide can be closely combined by electrostatic self-assembly, so as to give full play to the role of MgO template. The prepared samples exhibit three-dimensional (3D) interconnected hierarchical porous structure, large specific surface area (SSA) and a large amount of nitrogen (10.97 at.%) and oxygen (10.3 at.%) functional groups. Benefiting from their synergy, the optimized NHPC-700 electrode possesses a high specific capacitance of 295.3 F g −1 at 0.5 A g −1 , excellent rate characteristics and superior cycling performance (100.76 % capacitance retention after 10,000 cycles). Furthermore, the assembled NHPC-700//NHPC-700 symmetrical supercapacitor provides a high energy density of 15.16 Wh kg −1 in 1 M Na 2 SO 4 aqueous electrolyte. The results fully demonstrate that the obtained hierarchical porous carbon shows promising application in supercapacitors. • High content of heteroatom-doped 3D interconnected hierarchical porous carbon was synthesized. • The NHPC-700 electrode delivers large specific capacitance and great electrochemical stability. • The symmetrical supercapacitor shows high energy density and superior cycling stability.