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The hierarchical porous N/O co-functionalized carbon (HPNOC) was scalably prepared by using the low-cost and renewable blighted grains as the raw material coupled with mild KHCO3 activation for electrochemical capacitors (ECs).The elemental N was in situ doped in the obtained HPNOC without any N-containing additives.Remarkably,the obtained HPNOC was endowed with a large specific surface area (about 2 624 m2·g-1),high pore volume (about 1.35 cm3 ·g-1),as well as high-content N/O functionalization (about 1.9％ (in atom) N and about 10.2％ (in atom) O.Furthermore,the as-resulted HPNOC electrode with a high mass loading of 5 mg·cm-2 exhibited competitive gravimetric capacitances of about 373.6 F·g-1 at 0.5 A·g-1,and even about 260.4 F·g-1 at a high rate of 10 A·g-1;superior capacitance retention of about 98.8％ at 1 A·g-1 over 10 000 consecutive cycles;and high specific energy of about 9.6 W·h·kg-1 at a power of 500 W·kg-1,when evaluated as a promising electrode in 6 mol KOH for advanced electrochemical supercapacitors.More encouragingly,the green synthetic strategy we developed holds a huge promise in generalizing for other biomass-derived carbon materials for versatile energy-related applications.