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Investigating Stability Properties for Transition Metal Carbonate Precursors Using Universal Cluster Expansion Technique (UNCLE) as Cathodes for Li-Ion Batteries



Author(s)

M. T. Morukuladi¹, N. L. Lethole², M. C. Masedi¹, N. N. Ngoepe¹ and P. E. Ngoepe¹

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DOI:10.17265/2161-6213/2023.1-3.004

1. Materials Modelling Centre, University of Limpopo, Private Bag x1106, Sovenga 0727, South Africa
2. Department of Physics, University of Fort Hare, Alice 5700, South Africa

The universal cluster expansion technique was used in this study to determine the binary phase diagrams for the transition metal carbonate precursors MCO₃ (M: Mn, Ni, Co). The use of mixed cathode materials in lithium-ion batteries such as NMC (Ni, Mn and Co) formulations, is a strategic approach to optimize performance, enhance safety and address cost and environmental considerations in the rapidly evolving field of energy storage. This study focuses on the cost issue related to lithium ion batteries by investigating the manganese rich NMC since manganese is more abundant and cost-effective. We doped MnCO₃ with nickel and doped MnCO₃ with cobalt then ran cluster expansion calculations to generate binary phases. The binary phase diagrams generated indicated that doping MnCO₃ with nickel favours the Mn-rich side, while doping MnCO₃ with cobalt favours 50% Mn-rich and 50% Co-rich. We further extracted the most stable structures from both binary diagrams and determined their electronic, mechanical and vibrational stabilities using DFT (density functional theory) calculations within the LDA (local gradient approximation) with Hubbard parameter (U). The electronic properties revealed that both materials are semiconductors due to their narrow energy band gap obtained while the mechanical properties showed that structures are mechanically stable since their necessary conditions for trigonal and triclinic systems were satisfied.

Binary phase diagrams, mechanical properties, electronic conductivity, phonon dispersion curves.