All-solid-state batteries (ASSBs) are promising alternatives to conventional Li-ion batteries owing to their high energy density and flame resistance. Sulfide-based solid electrolytes (SEs) are crucial for the fabrication of ASSBs due to their high Li-ion conductivity and suitable mechanical properties which help in achieving strong interfaces. However, the commercial application of ASSBs is considerably limited due to factors such as long synthesis times and large amounts of energy consumption due to the synthetic processes. Korean researchers at Korea University report new synthetic process for sulfide-based Li-argyrodite type superionic conductor that can solve above the problems. The study appears in the journal Advanced Science in May. 

Li-argyrodite is considered to be a promising material for use in commercialized ASSBs due to its high ionic conductivity, thermodynamic stability, abundance, and liquid-phase (or solution) processability. However, the existing synthesis methods face various limitations that must be solved for practical applications. The conventional solid-state synthesis is intuitive and accurate, but presents low productivity since it achieves only small-scale reactions while requiring large amounts of energy and time. The wet process (solution or suspension-based) is more convenient and suitable for mass-production, but it is vulnerable to byproduct generation and nucleophilic attack by solvents. Therefore, the commercial application of ASSBs is considerably limited due to above the processing limitations. The researchers, led by Prof. Kim, simultaneously solved all problems in previous wet process by designing the process using microwave irradiation. 

Prof. Kim said that “We newly developed a facile and time-saving microwave-assisted wet-synthetic approach to overcome the processing limitations such as time and energy consumption, adverse solvent effect, and byproduct generation, for Li-argyrodite type superionic conductors. Moreover, we demonstrated the synthetic advantages such as ultrafast PS43- formation, lower solvent effect, and high LiCl solubility in the precursor via in/ex-situ characterizations.” This novel synthesis process increases the ease of fabricating next-generation ASSBs; furthermore, it significantly improves the performance of the ASSBs.”

Schematic diagram of wet-chemical synthetic approach for Li-argyrodite and in-situ monitoring results via Raman spectrocopy analysis during the process.

[Reference] S.-H. Hwang, S-D. Seo, D.-W. Kim, A Novel Time-Saving Synthesis Approach for Li-Argyrodite Superionic Conductor, Advanced Science, 10.1002/advs.202301707

[Main Author] Suk-Ho Hwang (Korea University), Seung-Deok Seo (Korea University), Dong-Wan Kim (Korea University)

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