Anchoring of K and Na on the surface of a novel SiC monolayer: First-principles predictions

Potassium-ion batteries (KIBs) and Sodium-ion batteries (SIBs) are highly promising next-generation energy storage technologies, thanks to their abundant resources, low cost, and minimal toxicity. However, their development is currently hampered by a lack of suitable anode materials. To address this challenge, we are investigating the novel structure of a SiC monolayer for sodium and potassium storage. Using first-principles calculations based on density functional theory (DFT), we aim to assess its potential as an anode material for KIBs and SIBs. Our findings reveal that SiC exhibits negative adsorption energies for K/Na adsorption on its surface. Furthermore, the SiC monolayer can efficiently achieve a high content of Na/K loading on both sides of its surface. Consequently, SiC showcases an exceptionally high theoretical capacity of 1336 mA h g−1 for both SIBs and KIBs, nearly three times higher than the commercial anode (graphite). Notably, Na/K ions exhibit substantial diffusivity on the SiC surface, characterized by a low energy barrier of 0.15–0.21 eV. Additionally, it is demonstrated that the semiconducting SiC monolayer transforms into a metallic state with excellent conductivity upon Na/K adsorption. These findings underscore the potential of the SiC monolayer as a promising candidate for SIBs and KIBs. •Na/K loading effect on the SiC sheet is deeply investigated for SIBs and KIBs.•As Na/K host material, a very low diffusion barrier (0.15–0.21 eV) is computed for rapid charging and discharging.•Na2Si16C16/K2Si16C16 could be used as a potential anode for SIBs/KIBs with average voltages of 0.99–89 V.•High Na/K storage capacity is achieved (1336 mA h g−1).