Cycling-Induced Interfacial Reconstruction and Lithium-Storage Kinetics in Additive-Free Electrophoretic Deposition-Derived Methylammonium Lead Bromide Electrodes

Abstract

Additive-free methylammonium lead bromide (MAPbBr3) electrodes were fabricated by electrophoretic deposition (EPD) directly on Cu foil to investigate Li-storage kinetics while minimizing electrochemical and interfacial contributions associated with polymer binders and conductive carbon additives. The EPD-derived film formed a porous particulate coating and exhibited an optical band gap of approximately 2.24 eV, confirming the retention of MAPbBr3 after deposition. Peak-resolved electrochemical analysis showed that Li storage does not proceed through a single intercalation pathway. The low-voltage cathodic peak showed mixed diffusion/interfacial behavior. In contrast, other redox peaks were mainly diffusion-controlled, with b-values close to 0.5. After cycling, energy dispersive spectroscopy revealed decreased N, Br, and Pb contents and increased F, P, and O signals, indicating MAPbBr3 reconstruction and electrolyte-derived interphase formation. Electrochemical impedance spectroscopy results showed that charge-transfer resistance decreased during discharge, suggesting kinetic activation of the reconstructed interface. This work establishes additive-free EPD as a powerful platform for revealing cycling-induced interfacial reconstruction and multistep Li-storage kinetics in MAPbBr3 perovskite electrodes.