Researchers at the Korea Electrotechnology Research Institute (KERI) have developed a nano-tin interlayer that allows all-solid-state batteries to operate effectively at a pressure of 2 MPa. 

According to the study, these cells achieved an energy density exceeding 350 Wh/kg. This level of energy density is notably higher than the 150–250 Wh/kg range typically found in the conventional lithium-ion batteries used in current electronics and electric vehicles.

“This is a world-leading achievement highlighting the potential of all-solid-state batteries to maximize performance without heavier systems or additional costs,” said the researchers in a press release.

The research team reported that large-area pouch cells using this interlayer retained more than 81 percent of their capacity after 500 charge-discharge cycles. 

By reducing interfacial resistance and suppressing the growth of lithium dendrites, the technology addresses a primary mechanical barrier to the commercial use of lithium metal anodes.

This development enables high-performance batteries to function without the bulky pressurization hardware that often adds excessive weight and volume to electric vehicle battery packs.

Overcoming technical barriers in solid-state chemistry

“All-solid-state batteries are regarded as the “dream battery” due to their significantly reduced risk of fire,” added the press release. They replace liquid electrolytes with solid materials to minimize fire risks, though maintaining efficient ion movement between solid layers remains a technical challenge. 

“Interfacial resistance arises from unstable physical contact between the solid electrolyte and electrode materials, thereby impeding efficient ion transport,” explained the press release.

Conventional solutions often involve applying external pressure in the tens of megapascals or utilizing complex coating processes that increase manufacturing costs and reduce packaging efficiency. 

The KERI team, led by Dr. Nam Ki-Hun at the Battery Materials and Process Research Center, applied a thin layer of nano-sized tin powder via transfer printing to create an additional pathway for ion transport and protect the lithium anode from degradation during cycling.

“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,” noted the researchers.

Simulations supported the experimental work

First-principles simulations conducted by Dr. Kim Youngoh at KERI’s Next-Generation Battery Research Center supported the experimental work. These simulations traced how tin-based alloys regulate lithium transport at the atomic and electronic levels, providing specific design principles for engineering future interlayer materials.

This computational approach reduces the reliance on trial-and-error in material selection and explains how the tin layer stabilizes the interface and lowers overall cell resistance.

Dr. Nam Ki-Hun stated that the study addresses large-area scalability and interfacial stability, both of which are required for the commercialization of all-solid-state batteries. Potential future applications for the technology include electric vehicles, humanoid robotics, and stationary energy storage systems.

Project leader Dr. Ha Yoon-Cheol added that the results represent progress toward securing a competitive advantage in the battery industry and strengthening strategic technological capabilities.

The research was co-authored by Kim Garam and Im So-Jeong, and a domestic patent application for the nano-tin interlayer technology has been filed in Korea.

The findings provide a practical method for producing high-capacity batteries that remain stable under mild operating conditions, simplifying the transition from laboratory prototypes to industrial manufacturing.

The study appears in the journal Advanced Energy Materials.