High-Throughput Screening of Li-Ion Solid Electrolytes with Experimental Evaluation

With an increasing demand for energy density and safety, all-solid-state Li secondary batteries are attracting attention, and one of the key materials is a solid electrolyte with high Li-ion conductivity. Recently, we developed the so-called corrugation descriptor to efficiently estimate the Li migration energy of materials [1]. The three-dimensional corrugation descriptor enables the automatic determination of diffusion pathways and migration energies, thus providing an efficient tool for evaluating, ranking, and optimizing materials with high Li-ion conductivity. We here [2] screened the Li-containing oxides included in the Inorganic Crystal Structure Database. Consequently, we identified new hexagonal oxides such as KLi₆TaO₆ (KLTO) having a low corrugation energy of 38 kJ mol^-1. First-principles calculations were performed to analyze the conductivity and migration mechanism of Li ions in KLTO, and predicted good conductivities and low migration energies provided with excess Li<i>_i</i>⁺ species. Our experimental results demonstrate that Sn-doped KLTO presents a conductivity of 1 × 10⁻⁵S cm⁻¹, a <i>σ</i>_Li of 6 × 10⁻⁶S cm⁻¹, and an activation energy of 36 kJ mol⁻¹, consistent with the corrugation energy and the migration energy of the first-principles calculations. On the other hand, experimental results suggested that the excess Li<i>_i</i>⁺ were not effectively introduced in the KLTO matrix, which could limit the experimental <i>σ</i>_Li values.<br/> <br/>Reference:<br/>[1] France-Lanord, Asahi, Leblanc, Lee, and Wimmer, <i>Sci. Rep.</i> <b>9</b>, 15123 (2019).<br/>[2] Suzuki, Lee, Masuoka, Ohta, Kobayashi, and Asahi, <i>Inorg. Chem.</i> <b>60</b>, 10371 (2021).