Exploring the Phase Stability of LiMn TM O (TM = Ni, Co, Cr, Ru) Cathode Materials in Lithium-Ion Batteries via the Cluster Expansion Method.

LiMnO has garnered significant interest as a potential cathode material due to its high electrochemical capacity, cost-effectiveness, and eco-friendliness. Nonetheless, its practical utilization is hindered by structural deterioration, which results in rapid capacity and voltage decay during cycling. To mitigate these challenges, cationic dopants have been incorporated to minimize structural collapse and enhance cathode material performance. Consequently, there is a strong desire to identify novel doped configurations as a remedial strategy for optimizing LiMnO properties. In this study, the stability of the LiMn TM O system (TM = Ni, Co, Cr, Ru) was explored using cluster expansion and Monte Carlo simulations. By employing cluster expansion, binary ground state diagrams were generated, revealing 73, 65, 90, and 83 newly stable phases in LiMn Ni O LiMn Co O, LiMn Cr O, and LiMn Ru O, respectively. The outcomes indicated that LiMnNiO, LiMnCoO LiMnCrO, and LiMnRuO represent the most stable doped phases within the LiMnO system. The application of Monte Carlo simulations enabled the assessment of high-temperature characteristics across the entire range of TM concentrations (0 ≤ ≤ 1), facilitating the construction of phase diagrams. The LiMn Ni O LiMn Co O, LiMn Cr O, and LiMn Ru O systems exhibited favorable mixing at temperatures of 850, 700, 1700, and 1300 K, respectively. These discoveries present a clear trajectory for optimizing the properties of LiMnO, offering valuable insights into conceptualizing innovative cathode materials characterized by enhanced stability and performance.