Fast Lithium Ion Conductivity in Layered (Li-Ag)CrS2.

Fast ionic conductors are of great importance for novel technologies in high-performance and rechargeable energy storage components with reliable safety and thermal stability. Here, we demonstrate a new concept of the pillar effect to construct two-dimensional (2D) fast Li+ conductors. Our developed layered LixAg1-xCrS2 (0 < x < 0.4) structure, with larger-radius Ag+ served as "pillars" to effectively rigidify the interlayer ionic channel, leads to multi-ion concerted migration behavior and thus contributes to low activation energy and fast Li+ diffusion. Consequently, the room-temperature ionic conductivity in (Li-Ag)CrS2 system reaches up to 19.6 mS·cm-1 for x is 0.31, which is comparable to that of currently best Li-ion conductors. Furthermore, the pillared structure exhibits unique ionic transport that the conductivity decreases as temperature elevated, which can be ascribed to the competition between Li+ and Ag+ migration through tetrahedral viods in 2D channel. We anticipated that pillar effect would pave a new way to explore new catalogue of Li superionic conductors.