Revisiting the origin of cycling enhanced capacity of Fe3O4 based nanostructured electrode for lithium ion batteries

Abstract We identify that reversible formation/decomposition of lithium oxide, pulverization of Fe 3 O 4 nanoparticles, and electrolyte reactions, are contributors to the enhanced capacity observed in the Fe 3 O 4 electrode upon long cycling. Introducing three-dimensional graphene foam to form a composite with Fe 3 O 4 nanoparticles largely increases the capacity (~ 1220 mA h g −1 vs. ~ 690 mA h g −1 ) and promotes the cycling induced capacity enhancement (an earlier capacity rise and a faster rising rate) of the Fe 3 O 4 electrode. Together with Fe 3 O 4 nanoparticles, the presence of graphene effectively promotes the electrolyte reactions and reversible formation/decomposition of lithium oxide. At the same time, activation of GF also occurs in the presence of Fe 3 O 4 nanoparticles, further increases the capacity of the nanocomposite.