Self-organized hetero-nanodomains actuating super Li⁺ conduction in glass ceramics

Easy-to-manufacture Li₂S-P₂S₅ glass ceramics are the key to large-scale all-solid-state lithium batteries from an industrial point of view, while their commercialization is greatly hampered by the low room temperature Li⁺ conductivity, especially due to the lack of solutions. Herein, we propose a nanocrystallization strategy to fabricate super Li⁺-conductive glass ceramics. Through regulating the nucleation energy, the crystallites within glass ceramics can self-organize into hetero-nanodomains during the solid-state reaction. Cryogenic transmission electron microscope and electron holography directly demonstrate the numerous closely spaced grain boundaries with enriched charge carriers, which actuate superior Li⁺-conduction as confirmed by variable-temperature solid-state nuclear magnetic resonance. Glass ceramics with a record Li⁺ conductivity of 13.2 mS cm^-1 are prepared. The high Li⁺ conductivity ensures stable operation of a 220 μm thick LiNi_0.6Mn_0.2Co_0.2O₂ composite cathode (8 mAh cm^-2), with which the all-solid-state lithium battery reaches a high energy density of 420 Wh kg^-1 by cell mass and 834 Wh L^-1 by cell volume at room temperature. These findings bring about powerful new degrees of freedom for engineering super ionic conductors.