Promoted cycling performance of metallic phosphide cathode for Na-O2 batteries

Na-O2 batteries have garnered increasing attention due to their high energy density and the abundance of sodium resources. However, the lack of efficient air cathodes has hindered their practical application, preventing the realization of stable and long cycling lifespans. Herein, we report the Na-O2 batteries using Fe-doped CoP nanowire arrays on carbon cloth (FeCoP-CC) as the air cathode, which exhibit a low overpotential of 200 mV, a high discharge specific capacity of 2853 mAh g- 1, and stable cycling performance over 200 cycles at a current density of 200 mA g- 1. The exceptional electrochemical performance can be attributed to the optimized adsorption of oxygen species by FeCoP-CC, which forms film-like NaO2 discharge products that facilitate the oxygen transport channels. Furthermore, the film-like discharge products and the extensive contact interface with the cathode accelerate charge transfer and effectively decompose during subsequent charging processes. This work provides valuable insights into the rational design of electrocatalytic air cathodes.