Constructing an Electron-Ion Dual-Conductive Network via MXene Shell for Stable Aluminum Powder Anodes in Aqueous...

Rechargeable aqueous aluminum-ion batteries (AAIBs) hold great promise for grid-scale energy storage, yet they lack stable anodes, especially when high-capacity aluminum powder is used (Al-p). Herein, we propose a core-shell structured MXene@Al composite anode to address these challenges. The composite is fabricated by uniformly encapsulating Al-p with conductive Ti₃C₂T_x MXene through mechanical ball milling and is then integrated into a self-supporting electrode on a zinc foam substrate. The MXene shell effectively prevents Al-p aggregation, constructs a continuous dual-electron-ion conductive network, and provides ample sites for Al³⁺ accommodation. Electrochemical tests reveal that the MXene@Al symmetric battery achieves a cycle life of 600 h with an overpotential of less than 40 mV at 0.1 mA cm^-2. The MXene@Al∥Cu half-cell demonstrates a Coulombic efficiency of 98.93% after 300 cycles, and the full cell with MnO₂ as the positive electrode maintains a capacity retention rate of 97.6% after 250 cycles at 0.2 A g^-1. Theoretical simulations further reveal that the strong charge accumulation at the MXene-Al interface and the enhanced orbital hybridization improve the interface stability. Meanwhile, finite element analysis confirms that the MXene coating homogenizes the electric field and mechanical stress distribution, thereby effectively suppressing dendrite initiation and propagation. This work provides a scalable strategy toward practical high-performance AAIBs.