Korean researchers have presented a new design principle to overcome the limitations of solid electrolytes, which have been vulnerable to air and suffered from low performance. The achievement is being evaluated as securing the commercial viability of next-generation all-solid-state batteries, often called the "dream battery."
According to the scientific community on Wednesday, a team led by Professor Seo Dong-hwa of the Department of Materials Science and Engineering at the Korea Advanced Institute of Science and Technology (KAIST), in collaboration with research teams from Dongguk University, Yonsei University and Chungbuk National University, successfully developed a solid electrolyte design technology for all-solid-state batteries that dramatically enhances ionic conductivity while maintaining structural stability even in air-exposed environments.
Unlike conventional lithium-ion batteries that use liquid electrolytes, all-solid-state batteries are drawing attention as next-generation batteries due to their lower fire risk. Halide-based solid electrolytes in particular, which contain halogen elements such as chlorine (Cl) and bromine (Br), offer excellent performance with high ionic conductivity but are highly vulnerable to moisture in the air.
The joint research team overcame the manufacturing difficulties by introducing a new structure based on an "oxygen anchoring" approach, which firmly stabilizes the structure by binding oxygen within the electrolyte. The tungsten element played a key role in this oxygen stabilization process.
As a result of introducing the new structure, the electrolyte maintained its stability without easily collapsing even when exposed to air.
Beyond stability, battery performance also improved. The technology was confirmed to have approximately 2.7 times higher ionic conductivity than conventional zirconium (Zr)-based halide solid electrolytes. The improvement came as changes in the internal structure of the electrolyte broadened and smoothed the movement paths of lithium ions, enhancing ion transport speed.
The research team applied the same strategy to various halide solid electrolytes based on zirconium (Zr), indium (In), yttrium (Y) and erbium (Er), confirming similar effects. This means it is a "universal design principle" applicable to a wide range of battery materials.
The study, which is credited with accelerating the development of solid electrolytes that simultaneously achieve air stability and high performance, was published in the international journal Advanced Energy Materials on Dec. 6.
"This research presents a new material design principle that optimizes multiple performance characteristics through a structural design strategy that simultaneously improves air stability and ionic conductivity," Professor Seo said. "We expect it will become a key benchmark for future all-solid-state battery research and process development."
