Electrochemical properties and energy storage performance of a GeC-Al₂SO heterostructure: A first-principles study

Two-dimensional van der Waals heterostructures provide chemically diverse interfacial environments that can effectively modulate alkali-ion storage behavior. Herein, density functional theory calculations are employed to evaluate the electrochemical properties and energy storage performance of the GeC-Al₂SO heterostructure. The calculated open-circuit voltage (OCV) profiles fall within the desirable range for anode operation under stable loading conditions. The theoretical specific capacity (TSC) increases progressively with ion coverage while maintaining structural integrity, reaching 704.37 mAh g⁻¹ for Li adsorption and 444.31 mAh g⁻¹ for Na adsorption, with the maximum volume variation limited to approximately 1.4%, indicating excellent mechanical stability during cycling. Climbing-image nudged elastic band (CI-NEB) calculations reveal low diffusion barriers of 0.163–0.459 eV for Li and 0.046–0.131 eV for Na, suggesting favorable ion transport kinetics and promising rate performance. These results indicate that the GeC-Al₂SO heterostructure exhibits promising electrochemical characteristics. Nevertheless, its potential application as an anode material for Li-ion and Na-ion batteries may be constrained by its thermal instability.