C4S Nanosheet: A Potential Anode Material for Potassium-Ion Batteries

Potassium ion batteries (KIBs) have received increasing popularity owing to their distinct advantages. We discover a hitherto unknown C4S nanosheet, a novel carbon-based material with carbon and sulfur consisting of pentagons and hexagons rings. The proposed C4S nanosheet is highly stable dynamically, thermodynamically, mechanically, and chemically, according to first-principles calculations. Moreover, the graphene-like C4S nanosheet is a prospective KIBs anode material, which has a metallic band structure, a relatively low diffusion barrier (0.07 eV), a large capacity (1340 mA h g−1), and an acceptable average voltage (0.44 V). Finally, we demonstrate good cycling stability of the C4S nanosheet. Our findings indicate that the proposed C4S nanosheet is a potentially favorable KIBs anode material.