Ti-Decorated SiC2 as a High-Performance Anode Material for Li-ion Batteries: A DFT-D2 Approach

Abstract

This study employs dispersion-corrected DFT-D2 calculations to investigate Li adsorption on pristine and Ti-decorated SiC₂, evaluating their potential as anode materials for Li-ion batteries. Key analyses, including adsorption energy, density of states (DOS), Bader charge, diffusion barrier, and open-circuit voltage (OCV), reveal that the incorporation of titanium (Ti) into SiC₂ significantly enhances the electrochemical performance, stability, and lithium atom diffusion characteristics of the material. Ti increases the adsorption energy, Eads, from -1.422 eV for SiC₂ to -1.641 eV for Ti-decorated SiC₂, strengthening the bond between lithium ions and the substrate. This stronger interaction improves capacity retention and cycling stability by reducing lithium desorption during cycling. While this increase in adsorption energy may slightly impede lithium diffusion, it contributes to greater structural stability and durability under high-rate charging and discharging conditions. Additionally, OCV is enhanced from 0.340 V in SiC₂ to 0.392 V in Ti-decorated SiC₂, improving the overall energy output. The lattice constants exhibit a minimal change of only 0.21%, indicating that lithium intercalation and deintercalation during battery charge and discharge cycles have an insignificant impact on volume variation. With a capacity of 965.25 mAh/g, Ti-decorated SiC₂ achieves a more favorable balance of stability, rate capability, and energy efficiency compared to undoped SiC₂, making it a promising material for practical, long-term applications in lithium-ion batteries.