▎ 摘　　要

Graphene/MnO2 composite was obtained by hydrothermal oxidation of the Mn-precursor on a graphene surface. The composite showed a fine dispersion of MnO2 nanorods over graphene nanosheets (GNs). The addition of MnO2 to GNs accelerated the oxygen reduction in the cathodes of Li-O-2 cells and promoted Li2O2 catalysis efficiently, compared with the pristine GNs. The power densities of the composite and the pristine GNs were 13.27 and 9.72 mW cm(-2), respectively. In addition, the cell containing GNs/MnO2 electrode exhibited stable cyclic performance. (c) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.