Construction Strategy of VO2@V2C 1D/2D Heterostructure and Improvement of Zinc-Ion Diffusion Ability in VO2 (B).

Abstract

VO2 (B) electrode material has relatively high capacity and good cycle stability. However, its poor rate performance limits its further development because of the strong interaction between zinc ions and the main lattice of VO2 (B). Herein, considering the design principle of rate performance improvement, we furnished a different scheme from a previous multistep method of the synthesis-modification strategy of pure VO2 (B). VO2@V2C 1D/2D heterostructure was constructed by controllable partial oxidation of V2C by a one-step hydrothermal method. The unique 1D/2D heterostructure improves diffusivity and reduces the diffusion size of zinc ions at the same time, which significantly improved the rate performance of VO2. The situation at the heterostructure interface is analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy. Combined with cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic intermittent title technology tests, the promotion mechanism for the rate performance of the derived VO2 is further explained. In addition, it is found that V2C MXene can be electrochemically activated when the voltage reaches 1.24 V. By further widening the voltage window to activate V2C, VO2@V2COx heterostructure was obtained, which realizes high capacity and maintains high rate performance in aqueous zinc-ion batteries. This work provides key insights for the design of high-rate-performance electrode materials for aqueous zinc-ion batteries.