Research HighlightsGraphene mesosponge: a step towards practical lithium-oxygen batteries
08/09/2023
Elucidating a unique sequential catalytic mechanism
Dr. Yu synthesizing edge-site-free GMS cathodes with the furnace.
Lithium-oxygen batteries (LOBs) hold great potential as the next-generation energy-storage devices due to their high theoretical energy densities. However, unlocking their full capabilities relies on understanding how catalytic carbon cathodes effectively mitigate the issue of high overpotentials in LOBs.
To explore this, a 2023 article by Yu, Nishihara and co-workers from AIMR investigated the effects of the graphene basal-plane (topological) defects and of the loaded Ru nanoparticles on the oxygen reduction/evolution reaction at LOB carbon cathodes1.
By synthesizing, characterizing, and monitoring the electrochemical performances of edge-site-free graphene mesosponge (GMS) cathodes with abundant defects and Ru loads, the team determined that while all GMS-based cathodes improved the discharge capacities compared to conventional carbon cathodes, the presence of Ru enhanced the cathode cycling stability. Moreover, the detection of two charge plateaus suggested a sequential catalytic mechanism involving both features, effectively reducing overpotential.
“The demonstration of sequential mechanisms was a significant step in LOB research,” says Yu. “It prompted us to use GMS to further study the catalytic effects of topological defects independently2, enabling us to confirm the two charge plateaus correspond to the decomposition of Li2O2 nanosheets by the topological defects, and the decomposition of Li2O2 toroids by the Ru nanoparticles.”
Future directions by the research team will focus on the design of free-standing and highly porous cathodes to realize practical high-performance LOBs.
(Author: Patrick Han)
References
- Shen, Z., Yu, W., Aziz, A., Chida, K., Yoshii, T. & Nishihara, H. Sequential catalysis of defected-carbon and solid catalyst in Li−O2 batteries. Journal of Physical Chemistry C 127, 6239−6247 (2023). | article
- Yu, W., Yoshii, T., Aziz, A., Tang, R., Pan, Z.-Z., Inoue, K., Kotani, M., Tanaka, H., Scholtzová, E., Tunega, D., Nishina, Y., Nishioka, K., Nakanishi, S., Zhou, Y., Terasaki, O. & Nishihara, H. Edge-site-free and topological-defect-rich carbon cathode for high-performance lithium-oxygen batteries. Advanced Science 10, 2300268 (2023). | article
This research highlight has been approved by the authors of the original article and all information and data contained within has been provided by said authors.
