A Mixed Ionic/Electronic Conductor Interphase Enhances Interfacial Stability for Aluminium‐Metal Anode

Abstract Metallic aluminium (Al) anodes are considered to be a promising alternative for large‐scale energy storage due to their inherent low cost, high safety and ideal weight/volume capacity (2980 mAh g −1 /8040 mAh cm −3 ). However, aluminum‐ion batteries (AIBs) based on room‐temperature ionic liquid electrolytes have encountered challenges in practical applications, such as side reactions and slow sluggish kinetics. The anode/electrolyte interface has attracted considerable attention for addressing the aforementioned challenges. Here, an AlCl 3 /Sn‐based mixed ionic/electronic conductor interface (MCI) is designed through a facile displacement reaction. The stability of the modified Al metal anode has been significantly enhance by superior charge transfer, excellent corrosion resistance and dense deposition morphology. Consequently, in symmetric cell, the Al@Sn electrode with MCI offers a lifespan for about 700 h (350 cycles) at 0.1 mA cm −2 . Moreover, combined with the graphite cathode, the pouch cells based on this novel anode present outstanding cycling performance, demonstrating a maintained capacity of 87.1 mAh g −1 after 450 cycles. This research presents an innovative Al‐metal anode for ionic liquid‐based Al‐ion batteries.