Lithium-oxygen batteries: High-energy, durable graphene-mesosponge cathodes redefine performance potential

Lithium-oxygen (Li-O2) batteries promise both extremely high energy density and reduced reliance on finite materials such as Co and Ni used in conventional lithium-ion batteries (LIB). However, the practical application of these benefits still requires the development of durable, high-capacity Li-O2 cathodes.

“Traditional LIB cathode designs not only fail to promote adequate atmospheric oxygen flow but also rely on binder materials that degrade on contact with reactive oxide species” explains Wei Yu, a member of an AIMR research team. “These aspects lead to limited battery capacity and cycle life—hindering the practical application of Li-O2 batteries.”

In a recent article, Yu, Nishihara and co-workers fabricated a Li-O2 battery cathode material using free-standing graphene mesosponge (GMS)-sheets with a hierarchically porous, minimally stacked, and edgeless design1. This graphene-based approach eliminated the need for oxygen-vulnerable binders.

“Our design’s structural specificity aims to enhance performance by achieving three objectives: hierarchical porosity for better oxygen and Li-ion flow; reduced stacking to maximize specific reaction sites; and the elimination of weak graphene edges for improved stability,” says Yu.

Through a multi-step fabrication process that precisely controls pore sizes across multiple scales, the team demonstrated this cathode material can achieve over 6300 mAh/g mass capacity, 30 mAh/cm2 areal capacity, and 480 mAh/cm3 volumetric capacity, along with a stable cycle performance surpassing 260 cycles at moderate current densities.

A future direction will focus on the rational design of Li metal anode to further improve the cycling stability of Li-O2 batteries under extreme conditions.

About the World Premier International Research Center Initiative (WPI)

The WPI program was launched in 2007 by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) to foster globally visible research centers boasting the highest standards and outstanding research environments. Numbering more than a dozen and operating at institutions throughout the country, these centers are given a high degree of autonomy, allowing them to engage in innovative modes of management and research. The program is administered by the Japan Society for the Promotion of Science (JSPS).

See the latest research news from the centers at the WPI News Portal: https://www.eurekalert.org/newsportal/WPI
Main WPI program site:  www.jsps.go.jp/english/e-toplevel

Advanced Institute for Materials Research (AIMR)
Tohoku University
Establishing a World-Leading Research Center for Materials Science:

AIMR aims to contribute to society through its actions as a world-leading research center for materials science and push the boundaries of research frontiers. To this end, the institute gathers excellent researchers in the fields of physics, chemistry, materials science, engineering, and mathematics and provides a world-class research environment.