Decorating carbon nanofibers with Mo2C nanoparticles towards hierarchically porous and highly catalytic cathode for high-performance Li-O2 batteries

Abstract

A facile synthesis of the hierarchically porous cathode with Mo2C nanoparticles through the electrospinning technique and heat treatment is proposed. The carbonization temperature of the precursors is the key factor for the formation of Mo2C nanoparticles on the carbon nanofibers (MCNFs). Compared with the Mo2N nanoparticles embedded into N-doped carbon nanofibers film (MNNFs) and N-doped carbon nanofibers film (NFs), the battery with MCNFs cathode is capable of operation with a high-capacity (10,509 mAh g−1 at 100 mA g−1), a much reduced discharge-charge voltage gap, and a long-term life (124 cycles at 200 mA g−1 with a specific capacity limit of 500 mAh g−1). These excellent performances are derived from the synergy of the following advantageous factors: (1) the hierarchically self-standing and binder-free structure of MCNFs could ensure the high diffusion flux of Li+ and O2 as well as avoid clogging of the discharge product, bulk Li2O2; (2) the well dispersed Mo2C nanoparticles not only afford rich active sites, but also facilitate the electronic transfer for catalysis.