Facile synthesis and electrochemical studies of Mn-Zn ferrite as anode for Li-ion batteries

In this study, Zn1-xMnxFe2O4 (x = 0.0,0.01,0.03,0.05) has been synthesized via a simple and facile high-energy ball milling route. X-ray Diffraction (XRD) analysis revealed the good highly crystalline phase with spinel structures for all the prepared samples with no traces of impurity except for x = 0.05, which shows an impurity peak of alpha-Fe2O3. The morphological studies were investigated to confirm the shape and size of the prepared samples using SEM and TEM. The average particle size estimated from SEM and TEM was found to be in the range of 100-200 nm. Energy Dispersive Spectroscopy (EDS) analysis confirms the homogeneous mixing of the elements in the prepared sample. The electrochemical performance of prepared Mn-doped ZnFe2O4 was analyzed using Galvanostatic Charge-Discharge (GCD), Electrochemical Impedance Spectroscopy (EIS), and Cyclic Voltammetry (CV). The pseudocapacitive and diffusive contribution for the charge storage mechanisms has also been analyzed. The results indicate that the Zn1-xMnxFe2O4 (x = 0.03) electrode exhibits excellent electrochemical behavior as compared to other prepared electrodes. Zn1-xMnxFe2O4 (x = 0.03) delivers excellent initial charge-discharge capacity of 1405 mAhg-1 and 900 mAhg-1 with a coulombic efficiency of 64.2%. After 200 cycles Zn1-xMnxFe2O4 (x = 0.03) delivered the discharge capacity of 502 mAhg-1 with capacity retention of 35%. The rate capability of Zn1-xMnxFe2O4 (x = 0.03) at a current density of 1000 mAg-1 was observed to be 434 mAhg-1. The EIS study revealed that Zn1-xMnxFe2O4 (x = 0.03) has the lowest Rct value and faster diffusion of Li ions which amplified its capacity retention even at higher current density, making it a suitable anode for LIBs.