Graphene-MnO composite and hollow-structured MnO powders are prepared by a simple one-pot spray pyrolysis process. The graphene content in the graphene-MnO composite powder is estimated to be 10 wt.%. The fine MnO crystals of size several tens of nanometers are uniformly distributed all over the graphene. The BET specific surface areas of the graphene-MnO composite and hollow-structured MnO powders are found to be 20 and 5 m(2) g(-1), respectively. The graphene-MnO composite powders have high initial discharge and charge capacities of 1207 and 849 mA h g(-1), respectively, at a current density of 500 mA g(-1). The initial discharge and charge capacities of the hollow-structured MnO powders are 1004 and 673 mA h g(-1), respectively. The discharge capacities of the graphene-MnO composite and hollow-structured MnO powders for the 130th cycle are 1313 and 701 mA h g(-1), respectively. (C) 2014 Elsevier Ltd. All rights reserved.