Defect-induced deposition of manganese oxides on hierarchical carbon nanocages for high-performance lithium-oxygen batteries

The cathode of lithium-oxygen (Li-O2) batteries should have large space for high Li2O2 uptake and superior electrocatalytic activity to oxygen evolution/reduction for long lifespan. Herein, a high-performance MnOx/hCNC cathode was constructed by the defect-induced deposition of manganese oxide (MnOx) nanoparticles on hierarchical carbon nanocages (hCNC). The corresponding Li-O2 battery (MnOx/hCNC@Li-O2) exhibited excellent electrocatalytic activity with the low overpotential of 0.73–0.99 V in the current density range of 0.1–1.0 A·g−1. The full discharge capacity and cycling life of MnOx/hCNC@Li-O2 were increased by ∼86.7% and ∼91%, respectively, compared with the hCNC@Li-O2 counterpart. The superior performance of MnOx/hCNC cathode was ascribed to (i) the highly dispersed MnOx nanoparticles for boosting the reversibility of oxygen evolution/reduction reactions, (ii) the interconnecting pore structure for increasing Li2O2 accommodation and facilitating charge/mass transfer, and (iii) the concealed surface defects of hCNC for suppressing side reactions. This study demonstrated an effective strategy to improve the performance of Li-O2 batteries by constructing cathodes with highly dispersed catalytic sites and hierarchical porous structure.