Comprehensive study on the physical and electrochemical behavior of Mn₀.₄Mg₀.₆Fe₂O₄/CeO₂/MnFe₂O₄ nanocomposite for energy storage applications

Abstract

A novel Mn₀.₄Mg₀.₆Fe₂O₄/CeO₂/MnFe₂O₄ nanocomposite was created and thoroughly examined for its structural, morphological, chemical, and electrochemical attributes, particularly for energy storage applications. XRD analysis confirms the coexistence of CeO₂, MnFe₂O₄, and MgFe₂O₄ crystalline phases, indicating the formation of a well-integrated multiphase composite. Electron microscopy (FESEM and TEM) reveals agglomerated, irregularly shaped nanoparticles with an average size of 13–14 nm, while EDS and elemental mapping confirm the uniform distribution of Mg, Mn, Ce, Fe, and O within the structure. Zeta potential measurements (∼ –22.7 mV) suggest good colloidal stability, and DLS analysis indicates the presence of larger particle agglomerates. XPS analysis identifies the constituent elements and confirms the presence of multiple oxidation states (Mn²⁺/Mn³⁺, Ce³⁺/Ce⁴⁺, Fe²⁺/Fe³⁺), pointing to the redox-active nature of the material. EPR spectroscopy shows a resonance signal with a g-factor of 2.48, indicating the presence of unpaired electrons typical of transition metal ions. Electrochemical characterization via cyclic voltammetry (CV) demonstrates pronounced pseudocapacitive behavior driven by surface redox reactions, while galvanostatic charge-discharge (GCD) profiles exhibit near-ideal triangular shapes and minimal internal resistance, reflecting good rate capability and efficient charge storage. These findings underscore the material's potential as a promising candidate for high-performance supercapacitor electrodes, offering a balance between energy and power density through its synergistic multi-phase composition and favorable electrochemical response.