Monolayer and bilayer siligraphenes as high-performance anode materials for potassium ion batteries: A first principles study

Potassium ion batteries (PIBs) show great promise in the next-generation renewable energy storage owing to the high energy density, earth abundance and low cost of potassium; however, the lack of an appropriate anode material is a major obstacle to realize high-performance PlBs. Herein, on the base of first-principles computations, we systematically explored the feasibility of emerging 2D SiC3 and SiC5 (called siligraphene) as the anodes of PlBs. Our computational results reveal that potassium atoms could be stably adsorbed on monolayer (bilayer) SiC3 and SiC5 with the adsorption energy in the range of -0.32 - -0.04 eV. Benefiting from the semi-metallic nature, the SiC3 (SiC5) monolayer could provide excellent conductivity for rapid electron transport. Moreover, the potassium diffusion barrier on SiC3 (SiC5) is only 0.12 (0.028) eV, indicative of a fast charging/discharging capability. The theoretical capacities of monolayer (bilayer) SiC3 and SiC5 are up to 1151.61 (628.15), 1065.95 (609.11) mA h/g. Meanwhile, the good mechanical property and favorable structural recovery of SiC3 (SiC5)-based 2D materials indicate an excellent cycle reversibility. All the encouraging results suggest that SiC3 (SiC5) could be utilized as an outstanding anode for advanced PIBs. (C) 2022 Elsevier B.V. All rights reserved.