Graphitic Carbon Nitride: A Rising Star Electrode Material for Supercapacitors

The rising global energy demand requires the development of high‐performance supercapacitors (SCs) that synergize high‐power density with substantial energy density. The pursuit of such energy storage devices is fundamentally related to the innovation of advanced electrode materials. Two‐dimensional graphitic carbon nitride (g‐C 3 N 4 ) has recently emerged as a compelling candidate, distinguished by its unique nitrogen‐rich structure, tunable electronic properties, and facile synthesis. This review provides a comprehensive and critical investigation of g‐C 3 N 4 ‐based materials for SCs. We systematically analyze the crystal structure, physicochemical properties, and synthesis methodologies of g‐C 3 N 4 , correlating these characteristics with their electrochemical performance. For the first time, a detailed comparative analysis is presented, categorizing strategies into the engineering of pristine g‐C 3 N 4 , heteroatom doping, and the construction of composites. We place particular emphasis on the superior performance of composites formed with conductive polymers, transition metal oxides/sulfides (TMOs/TMSs), graphene, MXenes, and other families, where synergistic effects enhance conductivity, stability, and charge storage capacity. Finally, we provide a critical outlook on the existing challenges and future possible directions, aiming to guide the rational design of next‐generation g‐C 3 N 4 ‐based electrode materials to unlock their full potential in SCs.