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TEM image of 3D pomegranate-like core@shell porous carbon structure and their comparison figure with the previous reported capacitance values of porous carbon materials. • A functionalized N and O co-doped three-dimensional hierarchical pomegranate-like porous carbon was rationally synthesized. • The hierarchical porous structure, high packing density and enriched N and O functional groups are crucial. • The symmetric suporcapacitor with the pomegranate-like porous carbon boots a high gravimetric (volumetric) energy density. Recently, the heteroatom-enriched porous carbons have received considerable attention on the research of electrodes with high gravimetric capacitances for supercapacitors (SCs). However, their relatively low volumetric capacitances have limited their practical applications due to very low packing density and poor ion diffusion at high mass loadings. In this study, by means of a facile modified chemical activation route, a functionalized N and O co-doped three-dimensional (3D) hierarchical pomegranate-like porous carbon (PPC) was rationally synthesized. First, A core–shell structured precursor composite for PPC was constructed. The polypyrrole (PPy) with the desired functional group was adopted as the precursor of the pomegranate-like core, and the polyacrylamide (PAM) hydrogel as the precursor of the pomegranate-like shell (designated as PPy/PAM). Then, after calcination of the PPy/PAM hydrogel precursor composites, a novel 3D hierarchical PPC was achieved. The as-obtained PPC offers short diffusion paths of ions, increases packing density and provides abundant active sites for pseudocapacitance by increasing self-oxygen–nitrogen-doped content. The performance tests of SC with PPC manifest that at 156 W kg−1 (109.7 W L-1), boosted energy density of 11.5 Wh kg−1 (8.05 Wh L-1) can be achieved. The as-obtained PPC is the promising electrode material of high-performance SCs for practical applications. [ABSTRACT FROM AUTHOR]