Graphitic carbon nitride: A comprehensive review towards supercapacitive energy storage applications

Towards the global energy demand for the development of efficient and eco-friendly energy storage systems, electrochemical supercapacitors are attractive for their fast charge-discharge capability, long cycle life, and safety profile. However, conventional electrode materials often face challenges in terms of cost, performance, and scalability. Graphitic carbon nitride (g-C₃N₄), a nitrogen-rich, metal-free material with a layered structure, offers a cost-effective and chemically stable alternative for next-generation energy storage. What distinguishes g-C₃N₄ from other graphene-like materials is its semiconducting nature and high nitrogen content, which provide abundant active sites for charge storage. Review explores comprehensive analysis of recent advancements in g-C₃N₄-based systems synthesis, characterization and supercapacitive performance to spotlight emerging trends along with the integration into flexible and wearable electronics, miniaturization into micro-supercapacitors, and adoption in solid-state configuration to overcome possessed by liquid configured devices. Pro and cons of g-C₃N₄ have been elaborated, overcoming the limitation to improve supercapacitive performance. Key modifications such as heteroatom doping, nano structurization, and hybridization with metal oxides, chalcogenides, polymers, and MXenes, which significantly enhance its electrochemical properties; well correlated through structural and surface engineering strategies enabling improved conductivity, increased surface area, and enhanced stability, contributing to better performance in supercapacitors applications. Special emphasis is placed on innovative composite architectures that incorporate pristine or doped g-C₃N₄ with functional materials, enabling enhanced charge storage, multifunctionality, and long-term stability. This work serves as a baseline for researchers and a strategic guide for advancing g-C₃N₄ based supercapacitors technologies.