Theoretical Evaluation of Newly Predicted VC4 Monolayer for Li-ion Batteries

Carbon-rich materials could increase the capacity and improve stability by decreasing the Li+-metal repulsive interactions. Herein, a new two-dimensional (2D) vanadium tetra carbide (VC4) was predicted using the first-principles calculations. The electrical characteristics, Li-anodic applications, and structural stability of VC4 were evaluated. With a comparatively less band gap, the bare VC4 displayed a semiconductor, while the Li+-loaded VC4 possessed a metallic nature. Using a multilayer Li top/bottom adsorption technique, a high Li storage capacity of 1353 mA h g−1 was observed in the VC4 monolayer. Notably, Bader's charge scheme confirmed a favorable and reversible electrochemical reaction between Li5VC4 and VC4. Significantly, VC4 serves as a host for high-performance lithium-ion batteries (LIBs), featuring a low barrier energy of 0.18 eV and an average open circuit voltage (OCV) of 0.52 V. Impressively, the variations of the structural parameters are within 10 % for a maximum Li+ intercalation, indicating high structural stability. These enthralling findings indicate that the monolayer VC4 sheet can be realized as an efficient Li host material for rechargeable LIBs.