Synthesis of free-standing reduced graphene oxide membranes with different thicknesses and comparison of their electrochemical performance as anodes for lithium-ion batteries

Free-standing reduced graphene oxide membranes (rGOMs) with different thicknesses and carbon contents are prepared via a simple, low cost, scalable, and eco-friendly two-step process. Scanning electron microscopy results show that rGOMs thicken with increasing GO solution concentration. The as-prepared free-standing rGOMs are directly used as anode materials for lithium-ion batteries without conducting additives or binders. The cycling performance and rate capability of the membrane electrodes are investigated and compared, and results indicate that not all of the synthesized rGOM anodes exhibit good lithium storage properties. Only those membranes with a coriaceous structure, approximately 2.5 mu m thickness, and suitable reduction degree present high performance for reversible lithium storage. Reasons for these findings are also provided.