Plasma-Assisted Synthesis of Defect-Rich O and N Codoped Carbon Nanofibers Loaded with Manganese Oxides as an Efficient Oxygen Reduction Electrocatalyst for Aluminum–Air Batteries

The oxygen reduction reaction (ORR) with sluggish kinetics on the cathode of aluminum–air (Al–air) batteries greatly limits their further development. Here, a new strategy is proposed to synthesize oxygen and nitrogen codoped carbon nanofibers loaded with manganese oxides (MnO/Mn2O3/ONCNF-n) as an efficient electrocatalyst for ORR by using oxygen plasma surface etching. The MnO/Mn2O3/ONCNF-3 exhibit superior ORR performance in an alkaline electrolyte, which is attributed to various active sites including N and O heteroatoms, vacancies, and manganese oxides. Additionally, the fabricated homemade Al–air battery (AAB) with MnO/Mn2O3/ONCNF-3 exhibits a maximum power density of 129.7 mW cm–2, demonstrating comparable performance to AABs based on the commercial Pt/C catalyst. This work provides a new approach of using O2 plasma for enhancing the ORR catalytic activities of carbon materials.