A method has been developed to enhance the stability of next-generation batteries that can drive more than 1,000 km on a single charge.
Professor Lee Hyun-wook's research team at Ulsan National Institute of Science and Technology noted on the 18th that they proposed a new design strategy to solve the oxygen gas generation problem associated with the cathode materials used in high-energy-density batteries. The research results were published in the international journal Science Advances on Feb. 19. Research teams from Korea Advanced Institute of Science and Technology (KAIST), Chung-Ang University, Pohang Accelerator Laboratory, University of California, Los Angeles (UCLA), University of California, Berkeley (UC Berkeley), and Lawrence Berkeley National Laboratory also participated in the study.
Cobalt lithium oxide can store up to 70% more energy than existing materials, gaining attention as next-generation technology that can extend the driving range of electric vehicles to 1,000 km. However, this material generates gas inside the battery when oxygen escapes from the cathode during charging, increasing the risk of explosion.
The research team first confirmed that oxygen is released from the cathode material when charging the battery near 4.25V. To address this issue, they proposed changing the transition metals inside the battery to more stable metals. Transition metals are metallic elements, such as nickel, cobalt, and ruthenium, that exchange electrons with lithium ions inside the battery.
Kim Min-ho, the first author and postdoctoral researcher at UCLA, explained, "While previous research focused on stabilizing oxidized oxygen to prevent it from being released in gas form, this study's distinction is that it concentrated on preventing the oxidation of oxygen itself."
Additionally, the research team confirmed through experiments that the method of changing transition metals is effective in preventing oxygen oxidation. In particular, when the research team replaced some of the ruthenium with nickel, they found through X-ray analysis that the generation of oxygen gas inside the battery significantly decreased. They also demonstrated through simulation calculations that the distribution of internal charges changed, making it more difficult for oxygen to oxidize.
Professor Lee Hyun-wook said, "Through various experiments and theoretical analyses, we provided a development direction for cathode material researchers" and added, "We will contribute to the development of batteries that increase energy density while ensuring safety."
References
Science Advances (2025), DOI: https://doi.org/10.1126/sciadv.adt0232