Facile and large-scale preparation of sandwich-structured graphene-metal oxide composites as anode materials for Li-ion batteries

Graphene-based metal oxides are desirable as potential anode materials for lithium-ion batteries (LIBs) owing to their superior electrochemical properties. In this work, sandwich-structured graphene-metal oxide (ZnO, NiO) composites are facilely synthesized on a large scale through self-assembly of graphene oxide nanosheets and metal ammine complexes, and then thermal decomposition of the self-assembled products. ZnO or NiO nanoparticles with diameters of 5∼10 nm are immobilized between the layers of graphene nanosheets, which may provide the space for accommodating the volume change of metal oxides during cycles, and highly improve the electronic conductivity of the composites. Accordingly, these sandwich-structured composites exhibit enhanced electrochemical performances compared to metal oxide particles or stacked graphene nanosheets. This facile synthesis method is very suitable for the large-scale production of three-dimensional graphene-based composites as high-performance anodes for LIBs.