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.