Methods for fabricating triazene-based graphitic carbon nitride films are provided. A substrate can be coated with silk fibroin, submerged in the central zone of plasma, and provided with microwave power. The substrate can then be dried to give a triazene-based graphitic carbon nitride film. Methods of the subject invention can be easily scaled up to industrial levels and produce triazene-based graphitic carbon nitride films that show excellent electrical properties as anodes in lithium-ion batteries.