Elemental Tuning of NMC Cathode Materials: Atomic Structural Variations Drive Performance Improvements

Layered lithium nickel-manganese-cobalt oxides (NMCs) have emerged as state-of-the-art cathode materials for lithium-ion batteries (LIBs) due to their high energy density and low cost. However, the underlying mechanism behind the performance decay that is associated with elemental compositions is not yet fully understood. This review aims to clarify the relationship between electrochemical performance and structural evolution by examining the role of individual elements in NMC materials. We investigated the impact of compositional variations on overall electrochemical property and provided a comparative analysis of single crystal (SC) and polycrystalline (PC) NMCs. The atomic-level interactions that connect structural characteristics and electrochemical properties were reviewed. We also discussed elemental variations in various modification strategies, including substitution, doping, concentration gradients, and surface coatings. The influence of primary and secondary particle sizes on battery performance was examined to guide the development of next-generation liquid and solid-state LIBs. The complex interplay between composition, morphology, and processing techniques provides valuable insights into designing a high capacity-retention cathode of Ni-rich and Co-free materials. Understanding the correlation between atomic structural variations is crucial in optimizing cathode material design to meet the increasing demands of high-energy-density and long-cycle-life batteries with both liquid and solid electrolytes.