Pseudo-Lithium Vacancies in Hydrogen Rich Li3OCl

The antiperovskite Li3OCl is a Li-ion solid electrolyte that has shown a wide variety of properties over a large range of temperatures. Previous reports align Li3OCl as a superionic conductor, however reproducibility has been poor due to its hygroscopic nature suggesting that reports are in fact, Li3 – xOHxCl. Most 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 HLi which relaxes off site to form what we define as a “pseudo-VLi” 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.