Halide Perovskite as Anode for Lithium‐Ion Batteries With High Rate Performance

Hybrid halide perovskites (HPs) exhibit soft lattice frameworks and intrinsic ion‐migration characteristics, suggesting potential tolerance toward foreign‐ion insertion beyond their established optoelectronic applications. However, their structural evolution and electrochemical reaction pathways under lithium insertion remain largely unexplored. In this work, CH ₃ NH ₃ PbI ₃ films were fabricated on Cu foil via a facile drop‐casting method and systematically investigated as model electrodes for lithium‐ion storage. The initial discharge capacity reaches 310.4 mA h g ⁻¹ and stabilizes at approximately 120 mA h g ⁻¹ after 160 cycles at moderate current density. Detailed electrochemical and structural analyses reveal a multistep lithiation process involving Li ⁺ insertion, partial reduction of Pb(II) species, and interfacial alloying reactions accompanied by progressive lattice degradation. The results provide insights into ion‐induced structural transformation and interfacial chemistry in HPs under electrochemical environments. Considering their compositional tunability and structural flexibility, HPs may serve as a versatile platform for exploring functional electrochemical layers.