CVD-Grown Phase-Pure V2C Nanosheets with Pseudocapacitive Behavior for Fast and Stable Lithium-Ion Storage

Abstract

We report a facile and scalable chemical vapor deposition (CVD) method for synthesizing high-quality, phase-pure V2C nanosheets using VCl3 and vanadium foil as dual vanadium sources and CH4 as the carbon source. Structural and compositional characterizations confirm the formation of crystalline, layered V2C nanosheets with uniform vanadium–carbon distribution and minimal impurities or surface terminations. When evaluated as anodes for lithium-ion batteries (LIBs), the V2C nanosheets exhibit outstanding performance, including a high reversible capacity of 385.2 mAh g-1 at 0.1 A g-1 over 500 cycles and excellent long-term stability with 90.3% capacity retention over 4100 cycles at 1 A g-1. Electrochemical impedance spectroscopy reveals reduced charge transfer resistance after cycling, while cyclic voltammetry indicates dominant pseudocapacitive behavior. Density functional theory (DFT) calculations further confirm the surface-controlled Li+ storage mechanism, showing strong ionic adsorption, low diffusion barriers (0.019 eV), and significant charge transfer. The pronounced pseudocapacitance is attributed to the unique physicochemical properties of V2C, including its 2D layered structure, metallic conductivity, high surface area, and phase purity. This work establishes CVD-grown V2C as a promising anode for high-performance LIBs and offers a viable route for MXene synthesis without corrosive etchants, advancing the design of next-generation energy storage materials.