Speaker
Dr
Ndanduleni Lethole
(University of Limpopo)
Description
Spinel lithium manganese (II) oxide (IV) (LiMn2O4) has been intensively studied as a positive electrode for rechargeable Li-ion batteries due to its abundance in the earth crust, low toxicity, and high theoretical capacity of 148 mAh/g. However this material has been reported to suffer from severe capacity fading, particularly at high temperatures during the charge/discharge process. This drawback makes the material incompetent for commercial application, though many attempts were made to improve its capacity sustainability. Recently, preliminary studies have shown that NaMn2O4 and MgMn2O4 have great potential for use in Na-ion and Mg-ion batteries. However, little has been reported on the physical and chemical properties of these compounds.
In this work, we perform first principles calculations to investigate the structural, thermodynamic, electronic and mechanical properties of NaMn2O4 and MgMn2O4, particularly the lattice constants, heats of formations, band structure, density of states, elastic constants and phonon dispersion curves. Furthermore, the operating voltages are also calculated. Calculations have been performed within DFT+U method as implemented in the Vienna Ab initio Simulation Package code. The calculated lattice constants are in good agreement with the experimental data to within 3 %. The electronic DOS and band structure calculations suggest that NaMn2O4 and MgMn2O4 are conductors due to the absence of energy band gap around the fermi level.
Level for award<br> (Hons, MSc, <br> PhD, N/A)?
N/A
Main supervisor (name and email)<br>and his / her institution
Ngoepe PE,
phuti.ngoepe@ul.ac.za
University of limpopo
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
No
Apply to be<br> considered for a student <br> award (Yes / No)?
No
Primary author
Dr
Ndanduleni Lethole
(University of Limpopo)
Co-author
Prof.
Phuti Ngoepe
(University of Limpopo)
Peer reviewing
Paper
Paper files:
