Recently, a new family of lithium-rich antiperovskites, Li 3 OA (A = halogen), which presents superionic conductivity, emerged as a promising both safe and commercially applicable solid electrolyte for lithium ion batteries. In this paper we employed classical atomistic quasistatic calculations to obtain the concentration of lithium vacancies and interstitials for stoichiometric samples of Li 3 OCl. The obtained concentrations as well as vacancy and interstitial migration energies reinforced the assumption that vacancies are the charge carriers in both stoichiometric and divalent metal doped samples, but raise the possibility that the high ionic conductivity in LiCl-deficient samples are in fact driven by interstitials, in opposition to what has been assumed so far. The Li 3 OCl stability at higher temperatures was investigated based on Gibbs energies of decomposition from 0 K up to 550 K. They are negative in the whole temperature range, which suggests that there exists a high Gibbs energy barrier between Li 3 OCl and starter materials preventing decomposition.

In this work a new empirical tolerance factor for compounds with pyrochlore structure is proposed. This suggested tolerance factor is based on experimental structural data and on the tolerance factors proposed. However, since it does not depend on the structural data, this new tolerance factor permits the prediction of some properties of these compounds directly. Also, a good structure stability field for the pyrochlore formation is observed when this tolerance factor is used.

Here, we report that in lithium-rich anti-perovskites (LiRAPs) with lithium halide deficiency, Li+ interstitials outnumber vacancies by 2–3 orders of magnitude, so that interstitials might be the actual charge carriers responsible for superionic conduction, as opposed to what has been assumed so far.

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Some lithium oxyhalides have been proposed as low-cost solid electrolytes for having room-temperature Li+ conductivity close to commercial liquid electrolytes, but with the advantages of enabling higher energy densities through...