Synergy Between Different Graphene Structures in Layer-By-Layer Assembly for Li-Air Battery Cathodes

Lithium-air or lithium-oxygen batteries widely known for its high energy density stand in the spotlight of world with an expectation that it could promote electric vehicles or high grid energy storages to the next level. Studies on the interface between carbon and catalyst or the reaction properties of each with respect to oxygen and electrolyte are underway. However, a few was reported on the structural characteristic of a cathode coated with two different carbons without a catalyst. In the current study, a sandwich-structured cathode was manufactured by successively alternating two different carbons in a layer-by-layer assembly manner onto a gas diffusion substrate. With a constant amount of total carbon but with a different number of layers a clear synergic effect was demonstrated in terms of both increasing the specific capacity and reducing charge overpotential. The results strongly indicate that the structural variance of cathode controlled by different carbon morphologies affects the overall performance of lithium-air batteries, not to mention their surface properties.