Nitrogen-doped　porous　carbon　materials　derived　from　agricultural　waste　are　considered　ideal　for　supercapacitor　applications.　However,　current　research　is　limited　to　nitrogen　doping,　with　insufficient　analysis　of　the　effects　of　different　nitrogen　species　on　capacitor　performance.　This　study　compares　four　different　nitrogen　sources,　revealing　that　the　MN-AC　electrode　material,　prepared　using　melamine　as　the　nitrogen　source,　effectively　enhances　the　physicochemical　structure　and　electrochemical　performance　of　the　electrode.　It　exhibits　the　highest　surface　nitrogen　content　(4.54　%)　and　an　optimal　mesopore　rate　(20.6　%),　with　a　significant　amount　of　pyrrole　nitrogen　(53.19　%　of　the　surface　content),　which　notably　improves　the　material＇s　polarization　and　wettability,　thereby　enhancing　its　electrochemical　performance.　At　a　current　density　of　0.5　A　g−1,　MN-AC　demonstrates　a　high　specific　capacitance　of　349.3　F　g−1.　Furthermore,　in　a　6　M　KOH　electrolyte,　it　achieves　an　energy　density　of　20.3　Wh　kg−1　and　a　power　density　of　169　W　kg−1.　DFT　analysis　indicates　that　pyrrole　nitrogen　increases　the　material＇s　dipole　moment,　enhancing　the　adsorption　of　electrolyte　ions　(K+).　©　2025　Elsevier　B.V.