The effect of niobium doping on lithium manganese oxide surfaces, LiMn2-xNbxO4: DFT study

  • B Ramogayana University of Limpopo
  • K P Maenetja University of Limpopo
  • P E Ngoepe University of Limpopo
Keywords: Spinel Surfaces, Density functional theory, Lithium-ion batteries

Abstract

Lithium manganese oxide (LiMn2O4) is one of the promising cathode material for lithium-ion batteries (LIBs), however, it suffers from capacity fading mainly due to surface manganese (Mn2+) ion dissolution during Charge/discharge processes. Although many studies focused on reducing Mn-dissolution, surface modification has proven to be an ideal method of reducing Mn2+ ion dissolution in secondary Li-ion batteries. In this study, the density functional theory calculations were carried out to study the bulk properties and investigate the effect of Nb surface doping on major LiMn2O4 spinel surfaces. Upon surface Nb doping, we observed a decrease in surface free energy as compared to the surface energies of pure surfaces, indicating that the surface stabilizes upon doping. However, the (001) surface remained the most stable facet, with a similar trend of increasing energies and decreasing stability, i.e. (001) < (011) < (111). Due to the stronger binding energy of Nb-O as compared to Mn-O, doping with Nb can suppress the Mn dissolution during intercalation and hence improve the electrochemical performance.

Author Biographies

B Ramogayana, University of Limpopo

Materials Modelling Centre, School of Physical and Mineral Sciences, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa

K P Maenetja, University of Limpopo

Materials Modelling Centre, School of Physical and Mineral Sciences, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa

P E Ngoepe, University of Limpopo

Materials Modelling Centre, School of Physical and Mineral Sciences, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa

Published
2022-01-24
How to Cite
Ramogayana, B., Maenetja, K., & Ngoepe, P. (2022). The effect of niobium doping on lithium manganese oxide surfaces, LiMn2-xNbxO4: DFT study. Suid-Afrikaans Tydskrif Vir Natuurwetenskap En Tegnologie / <i>South African Journal of Science and Technology</I&gt;, 40(1), 22-26. Retrieved from http://satnt.co.za/index.php/satnt/article/view/872
Section
Conference of the South African Advanced Materials Initiative

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