Electrochemical Behavior and Cycling-Induced Structural Changes in Benzylammonium Copper Chloride Electrodes for Lithium-Ion Batteries

This work reports the synthesis of the organic–inorganic copper chloride perovskite (C6H5CH2NH3)2[CuCl4] and its application as an electrode material for lithium-ion batteries. Hybrid copper halide perovskites have emerged as environmentally friendly alternatives to lead-based systems due to their structural versatility and chemical stability; however, their electrochemical energy storage properties remain largely unexplored. To the best of our knowledge, this is the first report investigating (C6H5CH2NH3)2[CuCl4] as an electrode material for lithium-ion batteries. The structural and morphological characteristics of the material were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and infrared spectroscopy (IR), confirming the formation of a layered perovskite structure. Electrochemical performance was evaluated by cyclic voltammetry and galvanostatic charge–discharge measurements. The material delivered an initial specific capacity of 114 mAh g−1 at a current density of 20 mA g−1 and maintained a coulombic efficiency around 99% after 100 cycles, indicating good cycling stability. The electrochemical behavior suggests that the reversible redox activity of Cu species contributes significantly to the charge storage mechanism. Postmortem XRD analysis revealed that the original perovskite framework was only partially retained after cycling, as several characteristic diffraction peaks remained while others disappeared, indicating partial structural decomposition. These results highlight the potential of chlorocuprate-based hybrid perovskites as alternative electrode materials for lithium-ion batteries.