In situ growth of mesoporous NiO nanoplates on a graphene matrix as cathode catalysts for rechargeable lithium-air batteries

NiO/graphene nanocomposites are fabricated via a solvothermal method. Scanning and transmission electron microscopy results indicate that the NiO nanoplates (length, similar to 100 nm) were homogeneously distributed on the graphene sheets. The electrochemical properties of the samples as active cathode catalysts for rechargeable Li-air batteries are evaluated by constant current charge-discharge cycling. The composites exhibit a reversible capacity of 1160 mAh g(-1) after 50 cycles at a discharge current density of 50 mA g(-1); this reverse capacity is much higher than that of pure NiO nanoplates (30 mAh g(-1)). Using graphene as a conductive matrix, a homogeneous distribution of NiO nanoplates is accomplished and graphene serves as a framework for loading as produced Li2O2 during the discharge process, resulting in the excellent electrochemical performance of the composites. The mesoporous structure of the NiO nanoplates is suitable for the transfer of O-2 and deposition of Li2O2 produced by the electrochemical reaction. NiO/graphene nanocomposites are a candidate material for high-capacity, low-cost, and nontoxic cathode catalysts in rechargeable Li-air batteries. (C) 2014 Elsevier B.V. All rights reserved.