Two-dimensional Ti3C2@CTAB-Se (MXene) composite cathode material for high-performance rechargeable aluminum batteries

Recently, aluminum-based batteries have received extensive attention and research in various countries because of their absolute advantages in terms of cost, energy density, and safety performance compared to other metals-based batteries. Herein, we successfully synthesized composite two-dimensional layered structure (Ti3C2@CTAB-Se) through HF etching, CTAB expansion and subsequent selenium treatment. Through electrochemical and XPS analysis of Ti3C2@CTAB-Se, it is known that Ti2+/Ti4+ and Se0/Sex+ undergo a reversible redox reaction during charging/discharging. Moreover, it is surprisingly found by density functional theory (DFT) that Ti3C2O2 after selenidation treatment is more conducive to the surface adsorption and diffusion of AlCl4− compared to Ti3C2O2. Therefore, Ti3C2@CTAB-Se exhibits excellent electrochemical performance. It shows a reversible discharge specific capacity of 583.7 mAh g−1 at 100 mA g−1, and its capacity is still 132.6 mAh g−1 after 400 cycles. In addition, Ti3C2@CTAB-Se exhibits absolute advantages in both voltage and capacity for graphite-based, oxides, sulfide and other electrode materials in aluminum-based and other batteries cathode materials. Therefore, the advantages of this work in voltage and capacity will promote the development of aluminum batteries.