First-principles study of Mn antisite defect in Li₂MnO₃

Abstract

Lithium-rich layered Li 2 MnO 3 is regarded as a new generation cathode material for lithium-ion batteries because of its high energy density. Due to the different preparation methods and technological parameters, there are a lot of intrinsic defects in Li 2 MnO 3 . One frequently observed defect in experiments is Mn antisite defect (Mn Li ). In this work, we study the energetics and electronic properties involving Mn Li in Li 2 MnO 3 through first-principles calculations. We find that Mn Li can reduce the formation energy of Li vacancies around it, but increase that of O vacancies, indicating that Mn Li could suppress the release of O around it and facilitate capacity retention. Both O and Mn near the Mn Li can participate in charge compensation in the delithiation process. Furthermore, the effect of Mn Li on the migration of Li and Mn is investigated. All possible migration paths are considered and it is found that Mn Li makes the diffusion energy barrier of Li increased, but the diffusion energy barriers of Mn from transition metal layer to Li layer are decreased, especially for the migration of the defect Mn. The insight into the defect properties of Mn Li makes further contribution to understand the relationship between intrinsic defects and electrochemical properties of Li 2 MnO 3 .

First-principles evaluation of MnO2 polymorphs as cathode material in lithium-ion batteries

“…It is worth noting that Li-Mn intermixing (interchange) can be common in Li-rich LMO cathode materials due to synthesis environments and migration of cations during charge/ discharge cycles. [45][46][47] To assess the likelihood of Li-Mn mixing, we calculate and compare the defect formation energy of Li-Mn exchange in all seven polymorphic phases of LiMnO 2 . An exchanged Li-Mn pair within 3 Å distance is placed in the supercells of LiMnO 2 and the results are summarized in Fig.…”

Revealing the different effects of VIB transition metals X (X = Cr, Mo, W) on the electrochemical performance of Li-rich cathode Li2MnO3 by first-principles calculations

“…7(c)), which is consistent with previous theoretical studies. 53,57 While the tetrahedrons on both sides of the path are TM tetrahedra, Li will directly pass through the O-O dumbbell structure, such as path 2c-4h2 (Fig. 7(d)) and path 4h1-4h2 (Fig.…”