Pseudo-lithium vacancies in hydrogen rich Li3OCl

Abstract

The antiperovskite Li₃OCl is reported as a superionic conductor, however, reproducibility has been poor due to its hygroscopic nature, suggesting that reports are in fact on Li_3−xOH_xCl. Most experimental and computational studies in the literature focus on pure Li₃OCl however, and do not take into account the role of hydrogen in the material. Here, we develop a full defect model of H-doped Li₃OCl, showing that the nominal Schottky disorder diminishes with hydrogen incorporation. Additionally, H helps to facilitate Li-ion mobility in Li₃OCl by firstly introducing rotatable OH species as well as forming H_Li which relaxes off site to form what we define as a “pseudo-V_Li” enhancing the ionic conductivity in line with experimentally observed values. Intentional hydrogen doping of hygroscopic materials constitute an underexplored strategy for enhancing ionic transport properties.