biostudies-literatureCao DBasic Energy SciencesOffice of ScienceDivision of Materials Research1544-1552https://www.ebi.ac.uk/biostudies/studies/S-EPMC10853963biostudies-literatureUnknown24(5)Lithium-metal (Li⁰) anodes potentially enable all-solid-state batteries with high energy density. However, it shows incompatibility with sulfide solid-state electrolytes (SEs). One strategy is introducing an interlayer, generally made of a mixed ionic-electronic conductor (MIEC). Yet, how Li behaves within MIEC remains unknown. Herein, we investigated the Li dynamics in a graphite interlayer, a typical MIEC, by using <i>operando</i> neutron imaging and Raman spectroscopy. This study revealed that intercalation-extrusion-dominated mechanochemical reactions during cell assembly transform the graphite into a Li-graphite interlayer consisting of SE, Li⁰, and graphite-intercalation compounds. During charging, Li⁺ preferentially deposited at the Li-graphite|SE inNano lettersLi Dynamics in Mixed Ionic-Electronic Conducting Interlayer of All-Solid-State Li-metal Batteries.PMC10853963DE-SC0024528DE-SC0018675DMR-2003343Cakmak EXu KTu QHOzcan SCao DZhu HZhao XJi TBilheux JBurch KSZhang YWang YGeiwitz MfalseLi Dynamics in Mixed Ionic-Electronic Conducting Interlayer of All-Solid-State Li-metal Batteries.Lithium-metal (Li⁰) anodes potentially enable all-solid-state batteries with high energy density. However, it shows incompatibility with sulfide solid-state electrolytes (SEs). One strategy is introducing an interlayer, generally made of a mixed ionic-electronic conductor (MIEC). Yet, how Li behaves within MIEC remains unknown. Herein, we investigated the Li dynamics in a graphite interlayer, a typical MIEC, by using <i>operando</i> neutron imaging and Raman spectroscopy. This study revealed that intercalation-extrusion-dominated mechanochemical reactions during cell assembly transform the graphite into a Li-graphite interlayer consisting of SE, Li⁰, and graphite-intercalation compounds. During charging, Li⁺ preferentially deposited at the Li-graphite|SE in2024-01-01T00:00:00Z2024 Feb2025-04-05T00:02:43.288Z2025-04-05T00:02:43.288ZS-EPMC108539633827009510.1021/acs.nanolett.3c04072