Multi-layer graphene assembled fibers with porous structure as anode materials for highly reversible lithium and sodium storage

Multi-layer graphene assembled fibers (MLG fibers) are synthesized by template-assistant decomposition of ethanol. Morphology and structure characterization results indicate that the synthesized fibers possessed a porous structure with diameters ranged from 1 to 1.5 μm and a length of 8-15 μm. The electrochemical properties of the fibers as anode materials for lithium-ion batteries and sodium-ion batteries are evaluated. The results indicate that MLG fiber electrode could deliver much better energy storage performance than that of chemical vapor deposited carbon fibers and other reported graphene-containing one dimensional materials. Benefited from their structure advantages, the MLG fiber electrode exhibits a high reversible capacity of 837 mAhh g−1 after 150 cycles at 250 mA g−1 in lithium-ion battery system, and a good capacity of 392 mAhh g−1 after 100 cycles at 100 mA g−1 in sodium-ion battery system. The attractive lithium and sodium storage properties can be ascribed to the porous fiber structure built by graphene sheets, which provide advantages including large surface area, easy pathways for electrolyte diffusion and low charge transfer resistance.