Capacitive Behavior Based on the Ultrafast Mass Transport in a Self-Supported Lithium Oxygen Battery Cathode

The pore structures of lithium oxygen battery cathodes play a significant role in their reversibility and lifespan by deciding the mass transport in cathodes. In the present work, a porous Co₃O₄/C modified wood-derived slice is used as self-supported lithium oxygen battery cathode. The straight tubes in vertical and horizontal directions inherited from wood vessels afford the cathodes facilitated paths for gas and ion transport, respectively. Furthermore, the homogeneous distribution of mesoporous Co₃O₄/C polyhedrons on tube wall of wood-derived substrates creates a uniform reaction interface in the cathodes. The ultrafast mass transport and uniform reaction interface lead to a capacitive contribution in battery capacity, owing to the fast kinetics that is free from the semi-infinite diffusion control. Accordingly, these merits enable the cathodes to have good reversibility and cyclability. The batteries can cycle more than 380 rounds without obvious overpotential variation at a current density of 1.0 mA cm^-2 within a capacity limitation of 1.0 mAh cm^-2.