Iron-cobalt bimetal decorated carbon nanotubes as cost-effective cathode catalysts for Li-O-2 batteries

Despite the extremely high theoretical specific capacity of lithium oxygen (Li-O-2) electrochemistry, low energy efficiency resulting from the large potential gap between the discharge and charge makes this system impractical. In this report, an iron cobalt bimetal decorated carbon nanotube (FeCo-CNT) composite was synthesized as a catalytic air cathode material for Li-O-2 batteries. An Li-O-2 battery using FeCo-CNT air electrodes exhibited higher efficiency (72.15%) than that of pristine CNTs (62.57%) as well as higher capacity (3600 mA h g(-1) vs. 1276 mA h g(-1)). Spectroscopic and electron microscopy analyses showed that the improved cell performances can be attributed to the catalytic effect of FeCo. As cost-effective non-noble metal catalysts, FeCo-CNTs demonstrated performance comparable to noble metal catalysts in Li-O-2 systems.