Synergistic Enhancement of Li-O2 Battery Capacity and Cycle Life Using Carbon Nanochain/Multiwall Carbon Nanotube Composites

Multiwalled carbon nanotube (MWCNT) Li-O₂ cathodes can achieve high gravimetric capacity. However, the macropores of these cathodes require a relatively large mass of electrolyte to fill, resulting in lower true gravimetric and volumetric capacities. Here we report a simple method to incorporate a mesoporous material, carbon nanochains (CNCs), into the macropores of MWCNTs, resulting in composite cathodes that fully utilize their pore structure to store Li₂O₂ product. The composite cathodes exhibit additional mesopores with an average diameter of ~100 nm. This results in dramatic increases in true gravimetric (21% to 870 mAh/g) and volumetric (>200% to 5664 mAh/cm³) capacities. The composite cathodes demonstrate improved electrochemical reversibility, increasing the cycle life by more than 50%.