Novel two-dimensional SiC2 monolayer with potential as a superior anode for sodium-ion batteries

Based on first-principles calculations, we report a new type of two-dimensional SiC2 (kust-alpha) composed of hexagons and decagonal rings. Kust-alpha had a stable two-dimensional structure with anisotropic mechanical properties and a small volume expansion of 8.12%. The feasibility of using the kust-alpha monolayer as a anode material for sodium-ion batteries (SIBs) was evaluated. The results show that kust-alpha exhibits a high theoretical capacity for SIBs, and reaches 1203 mAh center dot g(-1) on two sides, which is much larger than traditional graphite materials. Kust-alpha has an open circuit voltage that is much lower than other materials and a relatively low diffusion energy barrier, which shows its good potential as an anode material for SIBs. In addition, a possible facile synthesis route for the kust-alpha approach was proposed. These interesting findings provide a new negative electrode material for SIBs, and a new strategy was proposed to reduce the expansion of silicon-based electrode materials.