Alleviating oxygen evolution from Li-excess oxide materials through theory-guided surface protection

Alleviating oxygen evolution from Li-excess oxide materials through theory-guided surface protection

TitleAlleviating oxygen evolution from Li-excess oxide materials through theory-guided surface protection
Publication TypeJournal Article
Year of Publication2018
AuthorsYongwoo Shin, Wang Hay Kan, Muratahan Aykol, Joseph K Papp, Bryan D McCloskey, Guoying Chen, Kristin A Persson
JournalNature Communications
Volume9
Issue1
Date Published11/2018
Abstract

Li-excess cathodes comprise one of the most promising avenues for increasing the energy density of current Li-ion technology. However, the first-cycle surface oxygen release in these materials causes cation densification and structural reconstruction of the surface region, leading to encumbered ionic transport and increased impedance. In this work, we use the first principles Density Functional Theory to systematically screen for optimal cation dopants to improve oxygen-retention at the surface. The initial dopant set includes all transition metal, post-transition metal, and metalloid elements. Our screening identifies Os, Sb, Ru, Ir, or Ta as high-ranking dopants considering the combined criteria, and rationalization based on the electronic structure of the top candidates are presented. To validate the theoretical screening, a Ta-doped Li1.3Nb0.3Mn0.4O2 cathode was synthesized and shown to present initial improved electrochemical performance as well as significantly reduced oxygen evolution, as compared with the pristine, un-doped, system.

DOI10.1038/s41467-018-07080-6
Short TitleNat Commun
Refereed DesignationRefereed