RECENT ADVANCES ON STUDIES OF LITHIUM-ION BATTERIES IN BAR-ILAN UNIVERSITY: PART I. NEW CATHODE MATERIALS BASED ON Li(Ni_xCo_yMn_z)O₂ FAMILY (x+y+z=1)

This presentation summarizes the recent studies in Bar-Ilan University of materials for positive electrodes of Li-ion batteries. The materials included lithiated oxides of Ni-based family Li[Ni-Co-Mn]O₂ (layered, R-3m space group). and of Li-Mn-rich layered-layered xLi₂MnO₃^.(1-x)LiMO₂ (M=Ni, Co, Mn), 04+ of the above materials in relation to the electrode behavior, structural stability, and thermal reactions [1, 2]. For Li[Ni_0.5Co_0.2Mn_0.3]O₂ materials, using density functional theory calculations, we have shown that Al³⁺ doping is preferred at Ni sites and the thermodynamic preference follows the order: Ni>Co>Mn. It was concluded from XPS studies that the modified stable and less resistive interface on the Al-doped particles comprised the Li⁺-ion conducting centers like LiAlO₂, AlF₃, etc., which promote, to some extent, the Li⁺ transport to the bulk and therefore facilitate the electrochemical reactions [2]. We discuss also the following issues: ab-initio calculations of the preferential substitution of Zr⁴⁺ at Mn, Co or Ni sites; influence of Zr⁴⁺ and Mo⁶⁺ ions on the Li⁺/Ni²⁺ mixing, charge distribution, the lattice constants, as well as partial layered-to-spinel structural transformation and thermal characteristics in reactions with solutions.

[1] S. F. Amalraj, M. Talianker, B. Markovsky et al. J. Electrochem. Soc. 160 (2013) A2220.

[2] D. Aurbach, O. Srur-Lavi, C. Ghanty et al. J. Electrochem. Soc. 162 (2015) A1014.