Dual catalytic behavior of a soluble ferrocene as an electrocatalyst and in the electrochemistry for Na–air batteries

Abstract

Metal–air batteries are important power sources for electronics and vehicles because of their remarkable high theoretical energy density and low cost. In this work, we firstly investigate the electrochemical properties of sodium air batteries (SABs) with the addition of ferrocene in the electrolyte. Combining charge–discharge measurements with field-emission transmission electron microscopy images of the discharged air cathodes, our results have demonstrated that two different pathways with ferrocene as an electrocatalyst and involved in the electrochemistry during the charge process might be governed by the morphological features of the electrode caused by the deposition of Na₂O₂ in SABs. The SAB with ferrocene as a catalyst exhibits a high cycling performance of up to 230 cycles with a high capacity of 1000 mA h g⁻¹.