Heteroatom-doped hierarchical porous carbon for high performance flexible all-solid-state symmetric supercapacitors

Hierarchical porous carbon shows enormous potential in the field of energy storage due to the open three-dimensional (3D) interconnected porous structure, high porosity, high surface area and excellent conductivity. Herein, we develop a facile strategy to prepare heteroatom-doped hierarchical porous carbon derived from electrostatic self-assembly of chitosan and graphene oxide using potassium citrate as activator. The optimized hierarchical porous carbon exhibits well-developed 3D hierarchical porous framework, large specific surface area and massive nitrogen (4.17 at.%) and oxygen (18.33 at.%) functional groups. Due to their synergistic effect, the NGCA-600 electrode delivers a high specific capacitance of 406 F g –1 at 0.5 A g –1, good rate characteristic and superior cycle stability. Interestingly, the assembled NGCA-600//NGCA-600 all-solid-state symmetrical supercapacitor delivers a large energy density of 14.7 W h kg−1 and superior cycle stability in PVA/KOH gel electrolyte. The above results fully illustrate that the obtained hierarchical porous carbon have broad application prospects in supercapacitors.