Rice Hull Powder‐Derived Activated Carbons with Plentiful N and P Species for Supercapacitor with Excellent Rate Capacitance Characteristics

Porous carbons with plentiful nitrogen and phosphorus heteroatoms (CMs‐N/P‐n) derived from rice hull powder and melamine polyphosphate are synthesized for superior charge/discharge performance. In the amorphous CMs‐N/P‐n materials, a part of carbon atoms are graphitized, and the I _D /I _G ratios are 1.09, 1.00, and 0.99. In CMs‐N/P‐n, N heteroatoms are dominated by pyridinic and pyrrodic N forms and P species dispersed in the skeleton as PC, PO, and PO species. In 6 M KOH, the optimized CMs‐N/P‐850 demonstrates a conspicuous specific discharge capacity that is composed of a remarkable pseudocapacitance and a double‐layer capacitance (EDLC). At 0.5 A g ⁻¹ , the discharge value is 593.1 F g ⁻¹ . Under 20 A g ⁻¹ , the capacitance still remains 46.2%. The superior capacitive characteristics are closely linked with the high cavity space, unique aperture distribution, and co‐action of N and P species, which are favorable conditions for the accommodation and fast migration of OH ⁻ , and the generation of pseudocapacitance.