Owing to their high Li+ conductivities, mechanical sinterability, and solution processability, sulfide Li argyrodites have attracted much attention as enablers in the development of high-performance all-solid-state batteries with practicability. However, solution-processable Li argyrodites have been developed only for a composition of Li6PS5X (X = Cl, Br, I) with insufficiently high Li+ conductivities (∼10-4 S cm-1). Herein, we report the highest Li+ conductivity of 0.54 mS cm-1 at 30 °C (Li6.5P0.5Ge0.5S5I) for solution-processable iodine-based Li argyrodites. A comparative investigation of three iodine-based argyrodites of unsubstituted and Ge- and Sn-substituted solution-processed Li6PS5I with varied heat-treatment temperature elucidates the effect of microstructural evolution on Li+ conductivity. Notably, local nanostructures consisting of argyrodite nanocrystallites in solution-processed Li6.5P0.5Ge0.5S5I have been directly captured by cryogenic transmission electron microscopy, which is a first for sulfide solid electrolyte materials. Specifically, the promising electrochemical performances of all-solid-state batteries at 30 °C employing LiCoO2 electrodes tailored by the infiltration of Li6.5P0.5Ge0.5S5I-ethanol solutions are successfully demonstrated.
Bibliographical noteFunding Information:
This work was supported by the Technology Development Program to Solve Climate Changes and by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (nos. NRF2017M1A2A2044501, NRF-2018R1A2B6004996, and 2019R1C1C1009324) and by the National Research Council of Science & Technology (NST) grant by the Korea government (MSIT) (CAP-14-02-KITECH). S.-M.B. at Brookhaven National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the U.S. Department of Energy through the Advanced Battery Materials Research (BMR) Program under contract DE-SC0012704. The PDF research used beamline 28-ID-1(PDF) of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering