The layered LiNiO 2 structure is based on the ccp layers of oxygen anion lattice, with Li and Ni occupying in the octahedral sites, and was initially identified as an isostructural compound to the R3 " m LiCoO 2 cathode. The (low spin) t 2g 6 e g 1 configuration of Ni 3+ leads to pronounced Jahn-Teller (JT) distortions, resulting in larger volume changes during cycling compared to the layered LiCoO 2 . Since it is demanding to capture the dynamic JT distortion experimentally, the structure has commonly been described as an average high symmetry R3 " m structure, with six identical Ni-O bond lengths. First-principles studies identified a few distorted LiNiO 2 structures and several studies found the P2 1 /c structure with JT distorted octahedra arranged in a zigzag fashion as the ground state. The bond lengths of the distorted structure agree with the extended x-ray absorption fine structure data, which showed two sets of distinct bond lengths of 1.91 Å and 2.09 Å. The R3 " m structure, on the other hand, is not dynamically stable and gives an erroneous electronic structure (i.e. showing a half-metal rather than a small band gap semiconductor). Therefore, it is important to use the correct ground state structure in computational studies.