New Record Set for Solid-State Batteries in Japan

Researchers at Nagoya University in Japan have set an absolute record for conductivity in lithium-ion oxide solid electrolytes. According to ixbt.com, the ion movement mechanism in a material called LLNOF was identified, pushing its electrical conductivity to 16.3 mS/cm. This is a significant step toward ensuring safety and efficiency simultaneously in the field of solid-state batteries. This was reported by Ixbt.com reports.

It is well known that liquid electrolytes used in modern lithium-ion batteries can easily catch fire if damaged. For this reason, scientists worldwide are actively trying to transition to solid electrolytes. However, while sulfide and chloride analogs have high conductivity, they pose a risk of releasing toxic gases when reacting with moisture. Oxide and oxyfluoride materials are much more stable and superior in terms of safety, but until now, they have lagged behind their competitors in terms of ion mobility.

The LLNOF material and the new discovery

The LLNOF material first attracted attention in 2024, when its conductivity was 7 mS/cm. However, experts did not fully understand the reason for such rapid movement of lithium ions. To unlock this mystery, a research team led by Takeshi Yajima spent over a year growing millimeter-sized LLNOF single crystals. Subsequently, single-crystal diffraction was used to analyze the arrangement of atoms and their displacements.

The study revealed that the fluorine ion within the material shifts slightly when a lithium ion moves into a vacancy (empty space). This movement clears the path for lithium, significantly lowering the energy barriers required for ions to pass through the electrolyte. Simply put, fluorine does not play a passive role here; rather, its movement actively facilitates the rapid movement of lithium through the crystal.

Future prospects

By adjusting the ratio of lithium, lanthanum, and vacancies, scientists managed to reach a record conductivity of 16.3 mS/cm. This result refutes the widely held belief in the scientific community that high conductivity depends solely on easily deformable negative ions.

This discovery paves the way for designing a new generation of solid-state batteries that achieve high conductivity without compromising safety. In the future, this technology is expected to dramatically increase the performance and safety of batteries for electric vehicles and portable gadgets.