High performance Li-O2 battery using γ-MnOOH nanorods as a catalyst in an ionic-liquid based electrolyte

Li-O-2 batteries using the ionic-liquid based electrolyte consisting of 1-ethyl-3-methylimidazolium tetrafluoroborate and lithium bis((trifluoromethyl)sulfonyl)imide were investigated with carbon catalyst (Super P), alpha-MnO2 nanorods/carbon composite catalyst (Super P + alpha-MnO2) and gamma-MnOOH nanorods/carbon composite catalyst (Super P + gamma-MnOOH). It is demonstrated that gamma-MnOOH nanorods display higher electrocatalytic performance for O-2 reduction in ionic-liquid based electrolyte, compared with that of Super P and alpha-MnO2 nanorods. The Li-O-2 battery using gamma-MnOOH nanorods/carbon composite as catalyst displays a high discharge capacity of 9400 mAh/g at a low current density of 50 mA/g and can be stably cycled 100 times with a current density of 200 mA/g. (C) 2012 Elsevier B.V. All rights reserved.