Graphene-based architectures of tin and zinc oxide nanocomposites for free-standing binder-free Li-ion anodes

Abstract

Free-standing, flexible, and binderless binary ZnO-reduced graphene oxide (rGO), SnO2-rGO, and ternary ZnO-SnO2-rGO Li-ion anodes were produced by vacuum filtrating the mixture of metal oxides synthesized by sol-gel method and graphene oxide produced by Hummers method. These paper anodes were designed by being decorated with metal oxides between rGO layers. To compare nanocomposite anode structures, field emission gun-scanning electron microscopy, energy dispersive X-ray spectrometer, X-ray diffraction, and electrochemical analyses were applied. The results suggested that ternary ZnO-SnO2-rGO paper anode exhibited larger discharge capacity and capacity retention than the binary anodes even after 100 cycles. This finding is attributed to buffering effect of rGO on volume expansion of the anode structure designed by sandwich-type production and the synergic effect of ZnO-SnO2 oxides.