An interface-reconstruction effect for rechargeable aluminum battery in ionic liquid electrolyte to enhance cycling performances

Aluminum (Al) metal has been considered as a promising anode for rechargeable batteries due to its natural abundance and ultrahigh theoretical specific capacity. However, rechargeable aluminum batteries (RABs) using Al metal as anode display poor cycling performances owing to interface problems between anode and electrolyte. The solid-electrolyte interphase (SEI) layer on the anode has been confirmed to be essential for improving cycling performances of rechargeable batteries. Therefore, we use a pretreated Al metal anode that has been immersed in ionic liquid electrolyte for a period of time before battery assembly to remove the passive film and expose fresh Al to the electrolyte. Then the reactions of exposed Al, acid, oxygen and water in electrolyte are occurred to form a SEI layer in the cycle. The thin, uniform and stable SEI layer on Al metal anode allows safe charge-discharge cycling of Al/electrolyte/V₂O₅ for high discharge capacity and coulombic efficiency (CE). This work illustrates that a SEI layer is formed on Al metal anode in the cycle using a simple and effective pretreatment process and results in superior cycling performances for RABs.