Histidine-Derived N, O-Codoped Porous Carbon Materials as Supercapacitor Electrodes

Designing the pore structure and distributing the heteroatoms rationally are crucial to enhancing the performance of carbon-based supercapacitors. Herein, based on the coordination chemistry between the active functional groups in histidine and Zn²⁺, we developed a synergistic activation strategy to successfully fabricate N, O-codoped porous carbon (CHC-2-800). Uniform coordination enables ZnCl₂ to act as both a template and an activating agent during high-temperature carbonization, promoting the formation of a micropore-enriched structure, while ensuring a homogeneous distribution of N and O functional groups. The optimized CHC-2-800 exhibits a high specific surface area (1197 m² g^-1), balanced pore structure, and abundant active sites, delivering a specific capacitance of 227 F g^-1 at 0.1 A g^-1 and maintaining a specific capacitance of 95 F g^-1 at 20 A g^-1 in a three-electrode system. As a symmetric supercapacitor, it retains 95.7% capacitance after 40,000 cycles, demonstrating excellent cycling stability. This strategy effectively integrates a well-developed microporous structure with heteroatom modulation, offering a new approach for the design of high-performance carbon materials.