Graphitic carbon nitride (g-C3N4): Futuristic material for rechargeable batteries

The layered two-dimensional (2D) graphitic carbon nitride (g-C3N4) is a structural analogue of graphene and received great interest in the field of electrochemical energy storage. The peculiar features of g-C3N4 including nitrogen rich environment, earth abundance, good electronic conductivity, excellent physicochemical stability, fascinating electrochemical stability, and environment-friendliness enable them to use as electrode candidates in high-performance rechargeable batteries. The electrochemical performances of 2D g-C3N4 electrodes are excellent in terms of high capacity, high energy density and cycle life which is beneficial for metal-ion batteries. In the case of metal air batteries, the properties such as large surface area, porous architecture that creates massive reaction sites and thin-layer structural features hold by these materials produce favorable conditions for higher performance. In the present study, we discuss the applications of 2D g-C3N4 as electrode candidates as well as electrolyte fillers for rechargeable batteries in order to compete with the global energy demand. Initially, we discuss the crystal structure and peculiar properties of 2D g-C3N4 and various methods available for its synthesis are outlined thereafter. Finally, a detailed description of its application in rechargeable batteries such as lithium-ion battery, sodium-ion battery, lithium-metal battery, lithium‑sulfur battery, lithium-air battery, redox-flow battery, zinc-ion battery and aluminum-ion battery are given. The present review proclaims the development of novel 2D g-C3N4 for application in electrochemical energy storage devices, particularly for rechargeable batteries.