Two-Dimensional Lead Halide Perovskites As Emerging Electrode Materials For Electrochemical Supercapacitors

Abstract

The tunable optoelectronic properties and layered morphologies that enable rapid ion transport make 2D (two-dimensional) lead Halide Perovskites (HPs) promising candidates for energy storage applications. In this study, 2D perovskites were synthesized through an Inverse Temperature Crystallization (ITC) method and evaluated as high-performance electrode materials in electrochemical supercapacitors. XRD (X-ray diffraction) confirmed the formation of a highly ordered layered perovskite phase, while UV-Visible spectroscopy disclosed a direct band gap of ~2.38 eV. Field-emission scanning electron microscopy imaging revealed flake-like nanosheets (200–800 nm) that facilitate efficient charge diffusion. Electrochemical characterizations by Cyclic-Voltammetry, Galvanostatic Charge-Discharge, and Electrochemical Impedance Spectroscopy demonstrated excellent capacitive behavior, low internal resistance, and robust ion transport. The electrode exhibited a Specific Capacitance (SC) of 212 F/g at 0.5 A/g, retaining 150 F/g even at 5 A/g, indicating superior rate capability. Moreover, the device achieved an Energy Density (ED) of 29.4 Wh/kg with a Power Density (PD) of 1058 W/kg, while maintaining 20.8 Wh/kg at high Current Density (CD), confirming outstanding appraise performance and cycling stability. These findings highlight the structural and electrochemical compatibility of 2D lead HPs, making them strong candidates for next-generation high-performance supercapacitors.