Journal of Power Sources, Vol.393, 108-118, 2018
A horizontal zinc-air battery with physically decoupled oxygen evolution/reduction reaction electrodes
A horizontal Zn-air battery has been designed to enable the use of physically decoupled and catalytically efficient ORR and OER electrodes for discharge and charge, respectively. The horizontal design features a horizontally positioned ORR electrode and a vertically positioned OER electrode, allowing effective management of oxygen transport and pressure. The ORR catalyst (MnOx) and OER catalyst (Co-Fe alloy) are fabricated via one-step electrodeposition on carbon paper and Ni foam, respectively. MnOx is identified as a combination of Mn3O4 nanorods and alpha-Mn2O3 spheres. Co-Fe is deposited as a solid solution film with an oxidized surface. Electrochemical tests show that both catalysts have comparable or even better activity than their commercial Pt-Ru catalyst counterpart. The catalysts are cycled at 20 mA cm(-2) to examine their durability. Cycling potential affects catalyst durability, with improved lifetime under separate ORR and OER conditions compared with the full ORR-OER voltage range. The fabricated catalysts are assembled into a Zn-air battery for discharge-charge cycling tests and show the same average efficiency (58%) as commercial Pt-Ru catalysts.