Comparative Study of Sn and Pb Doping Effects on the Structural and Electrochemical Behaviour of 2D Halide Perovskites for Energy Storage Devices

Abstract

Because of their high surface area, efficient ion transport, and tunable electronic structures, 2D halide perovskites have been proposed as potential material for future energy storage. Here, inverse temperature crystallization (ITC) was employed to synthesize Sn- and Pb-doped 2D halide perovskites to examine the impacts of B-site cation substitution on their structural, optical, and electrochemical properties. Whereas SnBr₂ and PbBr₂ were the dominant precursors and dopants in 10% mole ratios of cross-doped samples, butylamine was the organic spacer to ensure stability in the layered structure. X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis spectroscopy were used to characterize its constituents. The findings indicated that the materials maintained satisfactory optical gap sizes, smooth platelet morphology, and high crystal structure. Electrochemical characterizations were carried out by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) in three-electrode conditions. Pb-doped sample performed better than the Sn-doped sample regarding cycling stability, specific capacity (160 mAh g⁻¹), and charge transfer resistance (800 Ω). All these findings indicate that the incorporation of Pb improves electron mobility as well as lattice stability, thereby enhancing redox kinetics and electrochemical durability. As per research, structural chemical engineering is a promising method for developing stable and efficient perovskite-based electrodes for future energy storage systems.