A thin-film protective layer transfer printing technology has been developed to solve the 'dendrite' problem, the greatest challenge for lithium-metal batteries, which are attracting attention as next-generation secondary batteries. The technology is expected to be applied in fields requiring high-energy lithium-metal batteries, such as electric vehicles.
The Korea Research Institute of Chemical Technology (KRICT) announced on the 13th that a research team led by Principal Researcher Seok Jeong-don of the Chemical Materials Research Division has developed a technology that effectively suppresses dendrite growth by applying a hybrid protective layer, a composite of solid polymer and ceramic, to lithium metal using a transfer printing method.
Dendrites are tree-like crystal structures that grow on the metal surface during the charging and discharging of a lithium-metal battery. The formation of dendrites increases the risk of short circuits and fire, and also shortens the battery's lifespan. Conventional wet processes to prevent dendrite formation use organic solvents, which can leave residues and increase the likelihood of damaging the lithium.
The research team developed an 'alumina-gold dual protective layer' and a 'ceramic-polymer composite hybrid protective layer,' and then, for the first time, implemented a transfer printing process to thinly attach the protective layer to the lithium metal surface.
The team's transfer printing process is a technology that fabricates the protective thin film on a substrate and then physically transfers it to the lithium metal using a roll-pressing method. Since no solvent is used when attaching the protective layer to the lithium, damage to the lithium can be prevented. This method can also overcome the non-uniformity of the lithium electrode thickness.
The alumina-gold dual protective layer developed by the team exhibited high mechanical strength and low interfacial resistance, leading to dendrite growth suppression and stable charging/discharging performance. The hybrid protective layer, which combines highly ion-conductive ceramic with a flexible polymer, suppressed dendrite growth between the lithium and the electrolyte and guided the flow of lithium ions, facilitating stable charging and discharging.
The research team also demonstrated a process capable of uniformly transferring an ultra-thin protective layer, 5μm (micrometers, 1μm = one-millionth of a meter) thick, onto a large area of 245×50mm.
The developed protective layer proved its effectiveness in a pouch cell, a type of lithium-metal battery. After 100 charge/discharge cycles, it achieved an 81.5% capacity retention rate, a low overpotential of 55.34mV (millivolts), and a 99.1% Coulombic efficiency (the ratio of discharge capacity to charge capacity), demonstrating a lifespan more than twice as long as that without the protective layer. Even under high-power conditions that fully discharged the battery within 9 minutes, it maintained 74.1% of its capacity.
The research team explained that the developed technology is a key element for the commercialization of high-energy-density lithium-metal batteries. This implies that it could be widely applied to high-energy storage devices such as electric vehicles (EVs) and energy storage systems (ESS) in the future. It is also expected to contribute to the realization of other next-generation secondary batteries beyond lithium-metal, such as all-solid-state and lithium-sulfur batteries.
The research team stated, “This study is a significant achievement that simultaneously overcomes the challenges of interfacial stability and the limitations of existing coating processes, which were hurdles to the commercialization of lithium-metal batteries, by combining a new protective layer material with a large-area transfer printing process.” The research findings were published as two papers in the international academic journal ‘Energy Storage Materials.’
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doi.org/10.1016/j.ensm.2025.104428
