Zhang et al. developed a green, and efficient strategy to fabricate N/P co-doped hierarchical porous carbons (NPHCs), using CaCO3 nanoparticles with 50 nm diameter as hard template, and also an inner-activator and studied its supercapacitive performances . In this study glucose, melamine, and biomass of phytic acid were used as carbon, nitrogen, and phosphorous precursors. The prepared NPHC material was carbonized at 850 ˚C, and for comparison purposes the NPC-850, NC-850, PC-850, NHC-850, and PHC-850 were synthesized without using CaCO3. From BET analysis, the SBET of NPC-850 was found to be as low as 62 m 2 g -1 , and after the addition of CaCO3 as a template, and also as an activator, the SBET was increased to 414 m 2 g -1 for NPHC-850. From XPS studies of NPC-850, the at% of N, O, and P were estimated as Upon the introduction of CaCO3 nanoparticles, the contents of N, P, and O heteroatoms were decreased to 8.72, 4.44, and 10.24%, respectively, which is probably due to the reaction between CO2 gas and active C atoms and heteroatom functionalities under high temperature. The electrochemical measurements were carried out in a three-electrode configuration, using 6 M KOH electrolyte solution, and Ni foam current collector. The fabricated NPC-850, 0.5NPHC-850, and 1NPHC-850 electrodes showed the specific capacitances of 137, 192, and 212 F g -1 , respectively at the current density of 0.5 A g -1 . 1NPHC-850 displayed the higher specific capacitance value, which indicates the increased SBET, and tune pore structures that affords rich ion-accessible active sites for both interfacial charge accumulation and heteroatom-related redox reactions, leading to a large capacitance. All the afore-mentioned three electrodes showed the capacitance retention upto 75% at the current density of 20 A g -1 . Further, a symmetric two electrode (1NPHC-850//1NPHC-850) supercapacitor cell was assembled in 1 M Na2SO4 aqueous electrolyte solution, which delivered the energy density of 10.61 W h Kg -1 at a power density of 400 W Kg -1 , and were able to retain 7.95 W h Kg -1 at a high-power density of 16 k W Kg -1 .