Rearrangement of Pore Structure-Enabled Micropore-Dominant\nN,O Co-Doped Carbon for Ultrafast Charge/Discharge Rate Supercapacitors\nat Commercial-Scale Mass Loading

N-doped\nporous carbon materials possess abundant pores and nitrogen\nfunctionalities, holding significant potential for supercapacitors.\nHowever, achieving precise control of the pore structure to enhance\nelectrochemical performance remains challenging in the large-scale\nproduction of commercial electrode materials. Herein, Chinese yam,\na rhizome plant rich in dopamine, is selected as the carbon precursor\nto prepare N,O-codoped hierarchical porous carbon (N/O-PC-3) via a\none-step carbonization and activation process. The pore structure\nis precisely controlled by adjusting the degree of aggregation of\nzinc-containing hydrolysates in biomass through the synergistic action\nof ZnCl<sub>2</sub> (activating agent) and NH<sub>4</sub>Cl (nitrogen\nsource). Due to its micropore-dominant pore structure, high nitrogen\n(10.5 at. %) and oxygen (13.1 at. %) content, along with good electronic\nconductivity and excellent wettability, N/O-PC-3 exhibits remarkable\nfrequency response, with an ultrahigh rate of up to 5 V s<sup>–1</sup> and high gravimetric, volumetric, and areal capacitances of 414\nF g<sup>–1</sup>, 311 F cm<sup>–3</sup>, and 23.8 μF\ncm<sup>–2</sup> at 1 A g<sup>–1</sup>, respectively.\nIt also demonstrates excellent rate capability (326 F g<sup>–1</sup> at 100 A g<sup>–1</sup>, 79% capacitance retention). Even\nat an ultrahigh mass loading of 15 mg cm<sup>–2</sup>, N/O-PC-3\nachieves a high gravimetric capacitance of 223 F g<sup>–1</sup>. The assembled N/O-PC-3 symmetric supercapacitor delivers an energy\ndensity of 22.9 W h kg<sup>–1</sup> at a power density of 102.9\nW kg<sup>–1</sup>, making it highly desirable for practical\napplication in energy storage. Additionally, this work offers a straightforward\napproach to precisely controlling pore structure in carbon materials.