Hollow versus nonhollow: The electrochemical preference in a case study of the conversion reaction of Fe3O4

Hollow benefits: A carbon-coated hollow-sphere-nanostructured Fe3O4 (h-Fe3O4@C) is prepared using a sacrificial hard template. Its hollow void of ∼80 nm diameter accommodates volume expansion during lithiation while the porous shell structure enables facile Li+ ion transfer and enhances accessibility to surface of the active material. The h-Fe3O4@C works kinetically faster as well as operationally more stable as an anode material of lithium ion batteries.