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

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.