Porous Co₃O₄ nanofibers applied as an efficient cathode catalyst for Li-air batteries

Porous Co₃O₄ nanofibers (Co₃O₄ NFs) composed with nanoparticles were fabricated by combining electrostatic spinning with subsequent calcination technology adopting Co(C₅H₇O₂)₃ as the precursor. The prepared porous Co₃O₄ NFs with specific surface area is up to 83 m²·g⁻¹, which can be successfully used as an efficient catalyst in Li-air battery. Porous Co₃O₄ NFs provide sufficient active sites and transport channels for the battery reaction, which is favorable for the battery reaction and greatly improves the discharge capacity of the battery. In addition, the addition of Co₃O₄ catalyst also greatly promotes the catalytic activity of the cathode and reduces the over-potential of the Li-air battery. Significantly, with the addition of Co₃O₄ catalyst, the morphology of discharge product Li₂O₂ can also be regulated. Li₂O₂ with smaller size are uniformly distributed on the surface of cathode, which is more likely to be decomposed during the subsequent charging process. Additionally, the volume effect of the electrode is greatly alleviated. Because of the above-mentioned advantages, the electrochemical performances of porous Co₃O₄ NFs/Super P carbon (Co₃O₄ NFs/SP)-based Li-air battery have been greatly improved. The discharge capacity of Co₃O₄ NFs/SP is up to 10600 mA·h·g⁻¹ at the current density of 50 mA·g⁻¹, and 100 continuous discharge-charge cycles can be achieved.