What do we need for the lithium-air batteries: A promoter or a catalyst?

LaSr-based perovskite materials are frequently studied as catalyst at the cathode of the lithium-air batteries (LAB). In this study, we compared Pb, Ba and Sr in the form of La0.65X0.35MnO3 (X = Pb, Ba, Sr) at the cathode of LAB in terms of total discharge capacity, cell cycling and discharge reaction products. The electrochemical characterization was carried out at the discharge current density of 200 mA g(-1) under dry oxygen atmosphere. The cell with La0.65Pb0.35MnO3, La0.65Ba0.35MnO3, La0.65Sr0.35MnO3 and Acetylene black carbon (alone) displayed capacity values of 7211 mAh g(-1), 6205 mAh g(-1), 6760 mAh g(-1) and 5925 mAh g(-1), respectively. The number of cycle and the operation time with the cells using La0.65Pb0.35MnO3, La0.65Ba0.35MnO3, La0.65Sr0.35MnO3 and Acetylene black carbon (alone) at 0.1 mA cm(-2) were 35 (650 h), 18 (300 h), 20 (76 h) and 11 (64 h), respectively. The cells with La0.65Pb0.35MnO3 showed columbic efficiencies ranging from 95 to 97% with superior performance compared to La0.65Ba0.35MnO3 and La0.65Sr0.35MnO3 with columbic efficiency of about 87%. The overpotential value was decreased approximately 300 mV by the use of La0.65Sr0.35MnO3 as a catalyst, whereas no change in the overpotential value was observed by the use of La0.65Ba0.35MnO3 and La(0.65)Fb(0.35)MnO(3) as a promoter. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.