Ionic conductivities in intercalation cathodes (e.g. LiNiO 2 ) are mostly governed by the mobility of Li + . The Li slab thickness, the electrostatic interactions between diffusing ions and the surrounding cations are considered to greatly influence ion mobility. Despite the fact that the Li slab thickness have increased in Li-excess systems (e.g. 1T-Li 2 NiO 2 ) to hold more Li (see Table ), it was speculated that Li diffusion is not promising as the overall available space for diffusion is reduced. The electrostatic repulsion between more closely arranged Li is a contributing factor. To estimate the activation energies for Li migration in Li 2 Ni 2 O 3 , we identified two plausible diffusion paths with a supercell containing a single Li + vacancy: (1) a direct hop from one tetrahedral site to the nearest neighboring tetrahedral site, with a hopping distance of 2.26 Å; (2) an indirect hop from one tetrahedral site to the next nearest tetrahedral site (~3.03 Å away) via an interstitial site that is ~1.68 Å away from the initial/end positions of the diffusing Li. Figure shows that a direct hop between the nearest Li tetrahedral sites is more favorable, with a barrier height of 0.34 eV. The direct hop maximizes the distance between the diffusing Li with the surrounding Li, therefore minimizes the unfavorable electrostatic/steric contributions from closely arranged Li. We also considered divacancy-like migration paths by introducing two vacancies in the supercell. The energy of the configuration with two clustered Li vacancies (~2.26 Å apart) is (~0.40 eV) higher than the configuration with two vacancies being ~3.03 Å apart (Figure ). Nevertheless, the barrier for a Li + to hop directly to the vacant site is lower than that of an indirect hop. The barrier height for the divacancy indirect hop is 0.17 eV lower than that of the monovacancy case and we attribute this reduced barrier to the lowering of electrostatic repulsion between fewer adjacent Li and the diffusing Li + . The barrier for Li + diffusion would theoretically decrease further when the system approaches a more Li dilute limit. However, this assumes that the structures remain stable in their highly delithiated states.