3D hierarchical porous α-Fe2O3 nanosheets for high-performance lithium-ion batteries

To develop a long cycle life and good rate capability electrode, 3D hierarchical

porous α-Fe2O3 nanosheets are fabricated on copper foil and directly used

as binder-free anode for lithium-ion batteries. This electrode exhibits a high

reversible capacity and excellent rate capability. A reversible capacity up to

877.7 mAh g −1 is maintained at 2 C (2.01 A g −1 ) after 1000 cycles, and even

when the current is increased to 20 C (20.1 A g −1 ), a capacity of 433 mA h g −1

is retained. The unique porous 3D hierarchical nanostructure improves electronic–

ionic transport, mitigates the internal mechanical stress induced by

the volume variations of the electrode upon cycling, and forms a 3D conductive

network during cycling. No addition of any electrochemically inactive

conductive agents or polymer binders is required. Therefore, binder-free electrodes

further avoid the uneven distribution of conductive carbon on the current

collector due to physical mixing and the addition of an insulator (binder),

which has benefi ts leading to outstanding electrochemical performance.