Significant advancements in clean energy technology are essential to achieving the United Nations” Sustainable Development Goals (SDGs), particularly in the realm of energy storage systems. High-energy-density batteries are gaining attention as promising candidates to help reach global carbon neutrality. Among these, lithium-oxygen (Li-O2) batteries are noteworthy for their theoretical energy density, which surpasses that of traditional lithium-ion batteries. However, their practical use has been hindered by issues related to cycle life and rapid degradation.
A research team from Tohoku University, led by Dr. Wei Yu, Professor Hirotomo Nishihara, and first author Zhaohan Shen, has made strides in addressing these challenges. Collaborating with researchers from Gunma University, Kyushu Synchrotron Light Research Center, Manchester Metropolitan University, and the University of Cambridge, the team synthesized a high-purity 13C-labeled graphene mesosponge (13C-GMS).
“Graphene mesosponge is a hollow-structured material with sponge-like characteristics, offering significant flexibility,” noted Nishihara. “Its unique structure allows for various applications, and in this case, we tailored it to investigate battery failure mechanisms.”
The innovative material features a high surface area and minimal edge sites, acting as a stable framework for loading polymorphic ruthenium (Ru) catalysts. By employing quantitative characterization and theoretical simulations, the team effectively determined whether battery failures stemmed from carbon cathode degradation or electrolyte decomposition.
The findings revealed that lowering the charge potential can mitigate carbon cathode degradation, while different Ru crystal phases lead to varying levels of electrolyte decomposition. “Our research identifies the “weakest link” in batteries—whether it is the cathode or the electrolyte—enabling us to target specific improvements for making Li-O2 batteries a more feasible option,” explained Yu.
This breakthrough not only clarifies a longstanding debate over the role of solid-state catalysts in Li-O2 batteries but also advances global efforts toward sustainable energy storage solutions. By uncovering the underlying mechanisms of battery failure, the study offers new design principles for the next generation of batteries, supporting the SDGs and fostering innovation in clean energy systems.
The results of this research were published in Applied Catalysis B: Environment and Energy on September 29, 2025, under the title “High-Purity 13C-labeled Mesoporous Carbon Electrodes Decouple Degradation Pathways in Li-O2 Batteries with Polymorphic Ru Catalysts.” The authors include Zhaohan Shen, Wei Yu, Alex Aziz, Takeharu Yoshii, Yoshikiyo Hatakeyama, Eiichi Kobayashi, Thomas Kress, Xinyu Liu, Alexander C. Forse, and Hirotomo Nishihara.
