Professor Dong-Wan Kim's team at Korea University developed a new process exceeding silicon substitution limits in lithium argyrodite solid electrolytes, crucial for these batteries, and explained the performance boost.

The research team introduced a ‘single-solvent-mediated approach’ wet process, successfully increasing the silicon substitution concentration in lithium argyrodite solid electrolytes to about 40%, surpassing previous limits. They further elucidated the fundamental principle behind this increased substitution limit and the enhanced ionic conductivity at high substitution concentrations through theoretical and experimental analysis.

Analysis showed the new process yielded solid electrolytes with reduced particle size and increased surface area to volume ratio. This facilitates more effective accumulation of substituted atoms within the space charge layer, the key mechanism for improved ionic conductivity. The resulting Li6.4P0.6Si0.4S5Br solid electrolyte exhibited high ionic conductivity (around 3.1 mS cm-1), demonstrating superior performance.

This research is highly valuable for scientifically revealing the core principles of solid electrolyte performance enhancement, paving the way for developing even more innovative all-solid-state battery materials.

Professor Kim Dong-wan emphasized the global first identification of the ‘mechanism’ significantly improving next-generation all-solid-state battery core material performance and their commitment to further research for safer, higher-performance all-solid-state batteries based on these findings.

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by Ministry of Science ICT and Future Planning (RS-2022-NR070534), by the National Research Council of Science & Technology (NST) grant by the Korea government (MSIT) (GTL24011-000)

Mechanism of Substitution Limited by Synthesis Method

[Reference]  Choi J. et al., (2025) “Breaking the Upper Limit of Substitution Concentration in Li Argyrodite Solid Electrolytes Using a Single-Solvent-Mediated Approach” Advanced Energy Materials, 

https://doi.org/10.1002/aenm.202500532

[Main Author] Ji Woong Choi (Korea University), Woong-Ju Kim (Korea University), Jin Gu Kang (Korea Institute of Science and Technology), Dong-Wan Kim (Korea University)

* Contact email : Professor Dong-Wan Kim (dwkim1@korea.ac.kr)