Layered carbon nitride bulk as a versatile cathode material for fast ion batteries

The development of high-comprehensive-performance cathode materials is significant and urgent for ion battery systems. Based on density functional theory methods, we systematically expand and investigate a porous and van der Waals layered bulk structure of carbon nitride as a versatile cathode material for various ion batteries. The calculated results indicate that the layered bulk carbon nitride structure is a semiconductor material with good thermal stability. The structure has high-density one-dimensional transport channels for fast K/Na/Ca ion migration with low activation energy barriers of only 0.125, 0.281, and 0.296 eV, respectively. The theoretical specific capacity, open-circuit voltage, and energy density can reach 137, 150, and 273 mA h g^-1, 3.788-3.614, 3.251-3.037, and 3.376-2.821 V, and 506.1, 470.8, and 847.3 W h kg^-1 for K, Na and Ca ions, respectively. Compared to common cathode materials, layered carbon nitride possesses significant advantages such as fast ion migration, high energy density, low cost, and environmental friendliness.