Abstract: Herein, we focused on the development of the V₄C₃ MXene composite bimetallic selenide heterostructure (V₄C₃@CuSe₂/CoSe₂) as a cathode material for aluminum batteries. This heterostructure was prepared through a Lewis melt salt etching and selenization process. By capitalizing on the synergistic effect between the bimetallic selenide and V₄C₃ MXene, V₄C₃@CuSe₂/CoSe₂ exhibited rapid charge transfer and demonstrated superior discharge specific capacity compared to V₄C₃ composite monometallic selenide. Furthermore, the incorporation of V₄C₃ improved the material's stability during charging/discharging. The initial discharge specific capacity of V₄C₃@CuSe₂/CoSe₂ reached an impressive 809 mAh g^-1 at 1 A g^-1. Even after nearly 3000 cycles, it retained a substantial capacity of 169.1 mAh g^-1. Ex-situ XPS analysis confirmed the reversible valence transitions of Cu, Co, and Se elements as the main energy storage reactions taking place in the cathode material. Density functional theory analysis provided further insights, revealing that the strong metallic behavior of the heterostructure stemmed from the charge rearrangement facilitated by the bimetallic selenide structure and the optimization of the energy level structure. Additionally, the presence of the bimetallic selenide structure significantly improved the adsorption efficiency of [AlCl₄]^-. Overall, this research contributes to the advancement of rechargeable aluminum ion batteries and presents a promising avenue for future developments in composite metal selenide structures and MXene-based materials.

Key words: Rechargeable aluminum batteries, V4C3 MXene, Bimetallic selenides, Heterostructure, Electrochemical performance