Fig. 7: Theoretical calculations on LiyTiS3 − xSex.
From: Activation of anionic redox in d0 transition metal chalcogenides by anion doping
a Projected density of states (pDOS) of Li2TiS3, Li2TiSe3, and Li2TiS1.5Se1.5. b Fukui functions computed to probe the electronic states involved in the oxidation process for the Li2TiS3, Li2TiSe3, and mixed Li2TiS1.5Se1.5 electrodes: these results clearly show that the holes generated upon oxidation (yellow volume) are mainly localized on the Ch (S and Se) anions for the pure-S and pure-Se electrodes, while the transition metal (Ti) is also involved for the mixed S/Se phases. Note that the Se selectivity in the mixed S/Se electrode is also clearly seen with a larger hole density around Se (pink atoms) much larger than around S (green atoms), therefore highlighting the Se selectivity in the mixed phases. c Atomic Bader net populations of the most oxidized S and Se atoms in the structure as a function of the Li content showing that Se is much more oxidized and S is much less oxidized in mixed S/Se compared to pure-S and pure-Se phases for an equivalent number of extracted lithium. All calculations were performed with the metaGGA SCAN functional (see “Methods” section).
