Anomalously High Ionic Conductivity of Li<sub>2</sub>SiS<sub>3</sub>-Type Conductors
Wenze Huang, Naoki Matsui, Satoshi Hori, Kota Suzuki, Masaaki Hirayama, Masao Yonemura, Takashi Saito, Takashi Kamiyama, Yuki Sasaki, Yongsub Yoon, Saheum Kim, Ryoji Kanno
Abstract
High Resolution Image Download MS PowerPoint Slide Solid-state electrolytes that exhibit high ionic conductivities at room temperature are key materials for obtaining the next generation of safer, higher-specific-energy solid-state batteries. However, the number of currently available crystal structures for use as superionic conductors remains limited. Here, we report a lithium superionic conductor, Li 2 SiS 3, with tetragonal crystal symmetry, which possesses a new three-dimensional framework structure consisting of isolated edge-sharing tetrahedral dimers. This species exhibits an anomalously high ionic conductivity of 2.4 mS cm –1 at 298 K, which is 3 orders of magnitude higher than the reported ionic conductivity for its orthorhombic polymorph. The framework of this conductor consists mainly of silicon, which is abundant in natural resources, and its further optimization may lead to the development of new solid-state electrolytes for large-scale applications.