A Novel Graphene Based Cathode for Metal–Air Battery

Abstract

The design and optimization of air-electrode structure play a prominent role in metal–air battery which is one of the most promising technologies among various electrochemical energy storage systems. Graphene offers porous path for the reactant transport in an electrode than conventional Carbon black powder, which helps in achieving high capacity metal/air battery. In house designed air diffusing substrate has been used in making the cathode of zinc–air battery. Flow Porometry technique also reveals that Graphene based air diffusion cathode had larger pore sizes, when compared to Vulcan XC Carbon based cathodes. A single cell was constructed with graphene based air diffusion cathode, alkaline electrolyte and bulk zinc sheet as anode. The single cell open circuit voltage was found to be 1.43 V. Open circuit voltage tests show that graphene based air diffusion cathode are more stable and could be operated for longer hours than carbon based air diffusion cathode. It has been observed that the static behavior of graphene based cathodes was better with higher durability compared to carbon based cathodes. The discharge characteristics show that the zinc/air battery with graphene based air cathode performs several folds longer than that of carbon based air cathode at 50 mA discharge current. The capacity of the constructed zinc/air battery was found to be 250 mA h.