Synthesis and Investigation of Optical, Magnetic, and Thermoelectric Properties of Li0.5Zr0.5Mg0.5Fe1.5O4 Spinel and First-Principles Characterization as an Electrode Material for Li-Ion Batteries

In this work, experimental characterizationsand densityfunctionaltheory (DFT) calculations were employed to investigate the influenceof cations distribution on optical, magnetic, thermoelectric, andelectrochemical properties of Li0.5Zr0.5Mg0.5Fe1.5O4 spinel. The crystal structurewas successfully refined in the Fd3 m space group. It was discoveredthat a migration between cations occupied the different spinel sites,induced by annealing temperature. The transmission electron microscopyimages revealed the formation of the compound of about 34 and 134nm after annealing at 500 and 900 K, respectively. The DFT calculationand visible-UV measurement proved that the semiconducting behaviorof the studied compounds was associated with an increase in the bandgap by increasing the annealing temperature. FC/ZFC measurements showedan increase in the Curie temperature from 561 to 598 K after increasingthe annealing temperature. Again, we found the presence of a superparamagneticbehavior for the nanometric compound. The thermoelectric propertiesproved a high merit factor ZT, reaching 0.85. In addition, the efficiencyof Li0.5Zr0.5Mg0.5Fe1.5O4 as a cathode for lithium batteries was examined byinvestigating the discharge process of Li0.5Zr0.5Mg0.5Fe1.5O4 at the early stagesof lithiation. This work studies the effectof cation distribution inducedby the annulling temperature process on the morphological, magnetic,and thermoelectric properties of Li0.5Zr0.5Mg0.5Fe1.5O4 spinel. Furthermore, the dischargeprocess of Li0.5Zr0.5Mg0.5Fe(1.5)O(4) at the initial lithiation stages was studied,thanks to DFT calculations.

Automated summary

In this study, experimental characterizations and DFT calculations were used to investigate the influence of cations distribution on the properties of Li0.5Zr0.5Mg0.5Fe1.5O4 spinel. The results showed that cations migration occurred between different spinel sites with increasing annealing temperature. The DFT calculations and measurements confirmed the semiconductor behavior of the compounds and an increase in bandgap with annealing temperature. The work also examined the discharge process of Li0.5Zr0.5Mg0.5Fe1.5O4 as a cathode for lithium batteries.