The synergistic effect of Lewis acidic etching V4C3(MXene)@CuSe2/CoSe2 as an advanced cathode material for aluminum batteries

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.