Mechanochemical Preparation of N,S-Doped Graphene Oxide Using (NH₄)₂SO₄for Supercapacitor Applications

N,S-dual-doped multilayer graphene oxide (NSMGO) has been successfully synthesized via mechanochemistry using (NH4)2SO4 as a nitrogen and sulfur source, featuring a simple, low cost, and green process. The content of N and S by elemental analysis was 5.82% and 1.33%, respectively. NSMGO was further characterized, showing that N was successfully doped into the aromatic rings but S was not. NSMGO showed an excellent electrochemical performance. The specific capacitance could reach 135 F/g when the current density was 1 A/g. This work provided a new and highly effective methodology for the preparation of sustainable and high-performance N,S-carbon with inorganic precursors.