Design and Electrochemical Performance of a Safe Open-System Cerium-Iron based Oxide Composite for Sustainable Zn-Ion Batteries

Abstract

This study reports the synthesis and characterization of cerium dioxide (CeO₂) and gamma iron oxide (γ-Fe₂O₃) using hydrothermal methods, as well as the development of a CeO₂/γ-Fe₂O₃ composite through solid-state techniques. Extensive characterization was conducted using X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), field emission transmission electron microscopy (FE-TEM), energy dispersive X-ray analysis (EDAX), and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of these materials were evaluated through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The CeO₂/γ-Fe₂O₃ composite demonstrated an impressive maximum capacity of 349 mAh g^-1, with a capacity retention of 91.4% and a coulombic efficiency of 98.4% at a current density of 0.5 A/g, showcasing its potential for use in aqueous zinc-ion batteries (AZIBs). Moreover, this battery configuration is considered a safe open system, offering greater environmental sustainability compared to conventional lithium-ion batteries.