Long-chain alkylammonium organic–inorganic hybrid perovskite for high performance rechargeable aluminon-ion battery

Recent advances in the use of organic-inorganic hybrid perovskites have been investigated in a variety of applications, such as solar cells, photodetectors, light-emitting devices, and lasers, because of their outstanding semiconductor properties. Furthermore, the perovskite structure can host extrinsic elements, making it a promising candidate for battery applications. Previous studies have shown that organic-inorganic hybrid perovskites can be suitable anode materials for both lithium- and sodium-ion batteries. However, multivalent rechargeable batteries with perovskite materials have not yet been realized. Herein, we studied the electrochemical performance of three-dimensional (CH₃NH₃PbI₃ (MAPbI₃) and long-chain alkylammonium (C₄H₉NH₃)₂(CH₃NH₃)₃Pb₄I₁₃ ((iBA)₂(MA)₃Pb₄I₁₃) thin films as electrode materials for rechargeable Al-ion batteries. Our results showed that (iBA)₂(MA)₃Pb₄I₁₃ presented a specific capacity of 257 mAh g^–1 at a current density of 0.1 A g⁻¹ and delivered 108 mAh g^–1 after 250 cycles at a current density of 0.3 A g⁻¹ with a retention of as high as 91 %, demonstrating a crucial role of isobutyl amine (C₄H₉NH₃) due to the unique hydrogen-bonding interaction of isobutyl amine that hinders the shuttle effect of polyiodide. The results open a new direction for the use of organic–inorganic hybrid perovskites for new secondary aluminum ion batteries.