A research team led by Dr. Nam Ki-Hun at the Battery Materials and Process Research Center of the Korea Electrotechnology Research Institute (KERI) has successfully developed a nano-tin (Sn) interlayer control technology to address interfacial instability between the lithium metal anode and solid electrolyte, a critical hurdle to the commercialization of all-solid-state batteries, often hailed as the next generation of batteries. The research was featured as a front cover article in Advanced Energy Materials (IF=26.0), a globally renowned journal in the field of energy and materials science ranked within the top 2.7% worldwide and has attracted widespread international recognition.
All-solid-state batteries are regarded as the "dream battery" due to their significantly reduced risk of fire. By replacing conventional graphite anodes with lithium metal, they offer improved energy density but a key technical challenge remains. "Interfacial resistance" arises from unstable physical contact between the solid electrolyte and electrode materials, thereby impeding efficient ion transport. In addition, lithium grows in tree-like structures during repeated charge–discharge cycles, called dendrite, reducing battery lifespan.
Laboratories have relied on adopting high external pressure in the range of tens of megapascals (MPa) or complex and costly coating methods to stabilize interfaces. However, such high-pressure systems when applied to real electric vehicles, etc. could outweigh the benefits as the pressurization system itself may become heavier than the battery. As a result, significant increase in manufacturing costs and reduced space efficiency within vehicles pose critical barriers to the commercialization of all-solid-state battery technology.
To address this challenge, KERI developed a thin interlayer composed of nano tin powder (nano Sn), a material with strong lithium affinity and storage capability, and stamped the interlayer onto the surface of the lithium metal anode through a transfer printing process. It reduces physical damage to the lithium metal by decreasing interfacial resistance, and also serves as an ion transport pathway, significantly lowering the overall resistance of the cell.
The research team applied this technology to a pouch cell and achieved over 81% capacity retention after 500 cycles even under a low pressure of 2 MPa. In addition, the cell delivered an energy density of >350 Wh/kg, exceeding that of conventional lithium-ion batteries (150–250 Wh/kg). This is a world-leading achievement highlighting the potential of all-solid-state batteries to maximize performance without heavier systems or additional costs.
This study was conducted in collaboration with Dr. Kim Youngoh, an emerging researcher at the Next-Generation Battery Research Center of KERI. Using simulations based on first-principles calculations, the team clarified how tin-based alloys control lithium transport and reduce interfacial resistance down to the atomic and electronic structure levels. Rather than being limited to experimental outcomes, the work offered a clear demonstration of scientific principles needed for designing next-generation battery materials by drawing on advanced theoretical and computational capabilities.
Dr. Nam Ki-Hun of KERI noted "The study is meaningful in that it secures both large-area scalability and interfacial stability, two essential factors for the commercialization of all-solid-state batteries, while also presenting a practical solution." He added "Efforts will continue to further refine the technology for real manufacturing processes so that it can become a key enabler for future industries depending on high-performance batteries, including electric vehicles, humanoid robotics, and energy storage systems (ESS). Dr. Ha Yoon-Cheol, co-corresponding author and project leader, also underscored "All-solid-state batteries are central to the global race for battery leadership. This study result represents a meaningful progress toward technological independence and securing a competitive advantage. It will contribute significantly to strengthening the strategic technological capabilities of Korea going forward."
The study lists Kim Garam (M.S., UST) and Im So-Jeong (KERI–Changwon National University joint program) as co–first authors. A domestic patent application has been completed for this technology. The work was carried out with support from KERI's research program and the Global Top Strategy Research Initiative (GT-3) of the Ministry of Science and ICT.
