N-doped porous carbon nanofibers inlaid with hollow Co3O4 nanoparticles as an efficient bifunctional catalyst for rechargeable Li-O2 batteries

Stable and high-efficiency bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are desired for the practical application of Li-O2 batteries with excellent rate performance and cycle stability. Herein, a novel hybrid bifunctional catalyst with carbon nanofibers inlaid with hollow Co3O4 nanoparticles and separate active sites for ORR and OER were prepared and applied in Li-O2 batteries. Benefiting from the synergistic effect of unique porous structural features and high electrocatalytic activity of hollow Co3O4 intimately bound to N-doped carbon nanofibers, the assembled Li-O2 batteries with novel catalyst exhibited high specific capacity, excellent rate capability, and cycle stability up to 150 cycles under a capacity limitation of 500 mAh g−1 at a current density of 100 mA g−1. The facile synthesis and preliminary results in this work show the as-prepared catalyst as a promising bifunctional electrocatalyst for applications in metal-air batteries, fuel cells, and electrocatalysis.