The world of battery technology is a complex and ever-evolving landscape, with researchers constantly striving to improve the performance, safety, and longevity of these essential energy storage devices. One of the most pressing challenges in the field of all-solid-state batteries, which are seen as the next generation of energy storage systems, is mechanical stability. These batteries, unlike conventional lithium-ion batteries, use solid electrolytes, which offer superior safety but can suffer from cracking and interfacial degradation during charge-discharge cycles. This issue has been a significant barrier to the widespread adoption of all-solid-state batteries, particularly in the context of electric vehicles, where high-performance, long-lasting batteries are crucial.
A groundbreaking development in this area comes from the Korea Research Institute of Chemical Technology (KRICT), where a research team led by Dr. Dong Wook Kim has developed a novel technology that addresses this critical challenge. The team, in collaboration with researchers from Yonsei University and Sungkyunkwan University, has created a composite electrolyte that incorporates an elastic ion-conductive polymer into sulfide-based all-solid-state batteries. This innovation aims to reduce cracking and interfacial degradation, thereby significantly improving battery durability and performance.
The key to this technology lies in the elastic polymer, which acts as a stress absorber and a strength enhancer. It functions similarly to a seismic damper in buildings, absorbing the stress generated by the expansion and contraction of electrode materials during charge-discharge cycles. This stress absorption helps to suppress crack formation and strengthens the adhesion between the electrode and electrolyte, ensuring stable contact and effective ion transport. Additionally, the elastic polymer fills internal voids within the electrolyte, providing additional lithium-ion transport pathways, which further enhances the battery's performance.
Experimental results are highly promising. Cells incorporating the elastic polymer demonstrated stable operation for over 2,500 hours during repeated lithium plating/stripping tests, which mimic the charge-discharge cycling behavior of real-world batteries. In contrast, conventional sulfide electrolytes experienced progressive interfacial degradation, leading to reduced performance over time. The composite electrolyte maintained a stable interface throughout the cycling process, ensuring consistent performance.
The technology's impact on performance under high-rate charging and discharging conditions is equally impressive. After 200 charge-discharge cycles, batteries without the elastic polymer retained only 22% of their initial capacity, while those with the elastic polymer maintained 75% capacity retention, more than three times higher. This indicates a significant reduction in performance degradation during long-term operation, making the technology highly attractive for practical applications.
One of the most significant advantages of this innovation is its reduced dependence on external stack pressure. Conventional sulfide-based all-solid-state batteries require high operating pressure to maintain interfacial contact between electrodes and electrolytes. However, batteries employing the elastic ion-conductive polymer exhibited relatively stable performance even under lower-pressure conditions. This finding is particularly meaningful for commercialization, as it may contribute to simplified battery structures and reduced manufacturing costs.
The research team plans to further validate the technology in large-format battery cells and electric vehicle operating environments. Dr. Kim emphasizes that this technology addresses one of the most critical challenges in sulfide-based all-solid-state batteries, the issue of mechanical stability. Dr. Seokmin Shin, President of KRICT, adds that they expect this technology to contribute to the development of highly safe next-generation batteries for electric vehicles and energy storage systems.
The research was published in the May 2026 issue of Energy Storage Materials, a leading international journal in the field of materials science. Dr. Kim served as the corresponding author, while Juhyoung Kim (KRICT–Yonsei University) and Hyo Won Bae (KRICT–Sungkyunkwan University) participated as co-first authors. This development marks a significant step forward in the quest for more efficient and reliable energy storage solutions, with the potential to revolutionize the electric vehicle industry and energy storage systems as a whole.
