Electronic Structure and Comparative Properties of LiNixMnyCozO2 Cathode Materials

We study the electronic structure and valence states in LiNixMnyCozO2 (NMC) materials and compare the resulting electronic, structural, mechanical, and thermal properties of a class of NMC compositions. The Jahn–Teller distortion in the transition metal (TM) octahedral complex allows us to determine the ionic states of the TM elements. The variation of Ni2+/Ni3+ and Co2+/Co3+ as the NMC composition changes alters the structural stability, electrical conductivity, lattice parameters, elastic modulus, and thermal stability. The theoretical predictions are in excellent agreement with the experimental results. Through intensive computational screening, we further show that long-range atomic ordering is absent in the NMC lattice due to the mixture of the ionic states and similar ionic radii of the TM elements. The first-principles modeling provides a theoretical foundation on a complete understanding of the physicochemical properties of NMC at the level of electronic structures.