CoFe2O4@multi-walled carbon nanotubes integrated composite with nanosized architecture as a cathode material for high performance rechargeable lithium-oxygen battery

In this paper, CoFe 2 O 4 @multi-walled carbon nanotubes (MWCNTs) nanocomposite is synthesized by a hydrothermal process and in-situ composite technique as cathode catalyst for rechargeable Li-O 2 battery (LOB). The as-prepared materials are characterized by XRD , TEM, XPS , BET, TG-DSC and FT-IR. Electrochemical discharge and charge capacity of MWCNTs and CoFe 2 O 4 @MWCNTs nanocomposite electrodes are investigated at current density of 0.02 mA cm −2 in the voltage window of 2.0–4.5 V. LOB with CoFe 2 O 4 @MWCNTs nanocomposite electrode shows an initial discharge capacity of 1245 mAh g −1 (electrode) , with reversible charge capacity of 1242 mAh g −1 (electrode) , while LOB with only MWCNTs electrode has discharge capacity of 545 mAh g −1 (electrode) and charge capacity of 543 mAh g −1 (electrode) . LOB with CoFe 2 O 4 @MWCNTs nanocomposite electrode shows good rate capability and cycle stability. After 15 cycles, the capacity of 1175 mAh g −1 (electrode) is still retained at the current density of 0.02 mA cm −2 while 723 mAh g −1 (electrode) is retained at 0.5 mA cm −2 . The capacity retention of CoFe 2 O 4 @MWCNTs nanocomposite electrode is 94.4% at 0.02 mA cm −2 and 92.1% at 0.5 mA cm −2 , respectively. During discharge, Li 2 CO 3 and Li 2 O 2 are the main discharge products. The results show that the electrochemical performance of MWCNTs is greatly enhanced with CoFe 2 O 4 introduced as core-shell structure.