Fe phthalocyanine supported by graphene nanosheet as catalyst in Li-air battery with the hybrid electrolyte

Non noble metal catalysts of cathode electrode for Li-air battery with hybrid electrolyte were prepared by the combination between Fe phthalocyanine (FePc) and different kinds of carbon such as graphene nanosheet (GNS), multi-wall carbon nanotubes (MWCNTs) and acetylene black (AB). The oxygen reduction reaction (ORR) of these FePc supported on carbon catalysts in alkaline media was studied. The onset potential of ORR for FePc supported on carbon shows -0.01 V vs. Ag/AgCl, which is near that of 20 wt% Pt/CB. Furthermore, rotating disk electrode (RDE) measurements show that the ORR mechanism is 4-electron pathway for all FePc supported on carbon. It is considered that the combination between FePc and carbon materials leads to synergic effect of electrocatalytic activity toward ORR. Moreover, the electrochemical performance of Li-air batteries exhibit that the FePc/CNTs not only provided a good discharge performance, but also showed a much more stable cycling performance than those of FePc/GNS and FePc/AB. It is thus considered that the electrochemical performance of Li-air battery is dependent on the kind of carbon materials. (C) 2012 Elsevier B.V. All rights reserved.