Fabrication of a three-dimensional interconnected mesoporous MnCo2O4 for rechargeable Li-O2 batteries

Rechargeable Li-O-2 batteries (LOBs) have attracted great attentions for its high theoretical energy density, and were considered to be the next potential energy storage devices. However, the high overpotential and poor cycling performance hinder the further development of LOBs. In this study, a binderfree air electrode of MnCo2O4 nanosheets supporting on the carbon cloth, was directly prepared by electrodeposition and calcination. MnCo2O4@carbon cloth possesses a flaky-porous and interconnected network nanostructure. The MnCo2O4@carbon cloth electrode could operate more than 108 cycles at 340 mA/g with a limiting specific capacity of 500 mA h/g. And it could deliver a first discharge specific capacity of 7238 mA h/g at 200 mA/g with the charge/discharge overpotential of 1.46 V. And it could achieve 3000 mA h/g when the current density was increased up to 800 mA/g. Such good electrocatalytic activity towards oxygen reduction reaction should derive from the high valence state of Mn3+ and Mn4+, and the three-dimensional interconnected mesoporous structure which can benefit oxygen diffusion and electrolyte infiltrate to form triple-phase regions in favour of oxygen reduction. (C) 2019 Elsevier B.V. All rights reserved.