A Recyclable Inert Inorganic Framework Assisted Solid-State Electrolyte for Long-Life Aluminum Ion Batteries

Abstract

The environmentally friendly and high-safety aluminum-ion batteries (AIBs) have attracted intense interest, but the extensive use of expensive EMIC-AlCl₃ electrolyte, strong moisture sensitivity, and severe corrosion of the Al anode limit their commercial application. Herein, we develop a solid-state electrolyte (F-SSAF) with an AlF₃ inert inorganic framework as the solid diluent, EMIC-AlCl₃ as the electrolyte, and FEC@EMIC-AlCl₃ (FIL) as the interface additive for solid-state AIBs (SSAIBs). The dissociation of Al₂Cl₇ ^- (AlCl₃-AlCl₄ ^-) into AlCl₄ ^- is promoted by AlF₃, which can facilitate the migration rate of AlCl₄ ^- active ions and simultaneously mitigate the corrosion of the Al anode. The introduction of an AlF₃ inert inorganic framework can also reduce the dosage of expensive EMIC-AlCl₃ and alleviate the moisture sensitivity of EMIC-AlCl₃. The FIL is introduced into the surfaces of both anode and cathode, thus in situ forming F-rich SEI and CEI films. The F-SSAF enables Al|F-SSAF|Al symmetric cells to achieve ultralong stable deposition and dissolution of Al up to 4000 h, and Al|F-SSAF|C full cells to achieve an unprecedented long cycle life of 10000 cycles with an average Coulombic efficiency of >99%. In addition, up to 80% of the AlF₃ inert inorganic framework can be recycled. This work provides a simple yet substantial strategy for low-cost, long-life, and high-safety SSAIBs.