KAIST Proposes Solid Electrolyte "Design Principle" to Accelerate Commercialization of All-Solid-State Batteries

by Jeong Ilwoong

Published 16 Apr.2026 08:17(KST)

A new "design principle" for solid electrolytes has been proposed to accelerate the commercialization of all-solid-state batteries. These batteries are often referred to as "dream batteries." However, solid electrolytes for all-solid-state batteries are vulnerable to air and suffer from low performance. The proposed design principle is significant because it addresses these vulnerabilities simultaneously, thereby improving both the safety and charging speed of the batteries.

AI-generated image. KAIST

KAIST announced on April 16 that the research team led by Professor Donghwa Seo from the Department of Materials Science and Engineering, together with research teams from Dongguk University, Yonsei University, and Chungbuk National University, have developed a solid electrolyte design technology for all-solid-state batteries. This technology maintains structural stability even when exposed to air and dramatically increases ionic conductivity.

All-solid-state batteries are attracting attention as next-generation batteries because they have a lower risk of fire compared to lithium-ion batteries that use liquid electrolytes. In particular, halide-based solid electrolytes, which contain halogen elements such as chlorine (Cl) and bromine (Br), offer high ionic conductivity and are advantageous in terms of performance.

However, they are susceptible to moisture in the air, which can easily degrade their performance. They are also known to be difficult to manufacture and handle.

To solve these issues with halide-based solid electrolytes, the joint research team introduced a new structure called "Oxygen Anchoring." This method stably binds oxygen within the electrolyte, making the structure more robust. Tungsten plays a key role in this process.

(From the bottom row, left to right) Dr. Jae Seung Kim of Seoul National University, Professor Donghwa Seo of KAIST, Researcher Heeju Park of KAIST, Researcher Jiwon Seo, Researcher Jinyoung Choi; (from the top row, left to right) Researcher Haeyong Kim of Dongguk University, Professor Eunyeol Lee of Chungbuk National University, Professor Kyungwan Nam of Dongguk University, Professor Yunseok Jung of Yonsei University. KAIST

When this new structure was applied, the halide-based solid electrolytes maintained their structural integrity even when exposed to air and did not collapse easily. Battery performance was also improved. As the internal structure of the electrolyte changed, the pathways for lithium ions became wider and smoother, resulting in faster ion movement.

In fact, the new material with incorporated oxygen showed ionic conductivity about 2.7 times higher than that of conventional zirconium (Zr)-based halide solid electrolytes.

Another feature of this technology is that it is not limited to a specific material. The joint research team confirmed similar effects when applying the same design method to various halide solid electrolytes based on zirconium (Zr), indium (In), yttrium (Y), and erbium (Er). This demonstrates the "universality" of the design principle developed by the team, proving that it can be applied to a wide range of battery materials.

The joint research team expects that this technology will contribute to the development of solid electrolytes that combine air stability with high performance.

Professor Seo stated, "A new material design principle has been proposed that optimizes 'multi-functionality' through a structural design strategy enhancing both air stability and ionic conductivity. We hope that the results of our collaborative research will serve as a key indicator for future research and process development of all-solid-state batteries."

This research was jointly authored by Dr. Jae Seung Kim (currently at Seoul National University) and researcher Heeju Park from KAIST, as well as researcher Haeyong Kim from Dongguk University, who served as co-first authors. The results were published in the international journal Advanced Energy Materials on March 6.