Research Highlights

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.

(Author: Patrick Han)