Three-Dimensional Nanoporous Fe2O3/Fe3C-Graphene Heterogeneous Thin Films for Lithium-Ion Batteries

Three-dimensional self-organized nanoporous thin films integrated into a heterogeneous Fe2O3/Fe3C-graphene structure were fabricated using chemical vapor deposition. Few-layer graphene coated on the nanoporous thin film was used as a conductive passivation layer, and Fe3C was introduced to improve capacity retention and stability of the nanoporous layer. A possible interfacial lithium storage effect was anticipated to provide additional charge storage in the electrode. These nanoporous layers, when used as an anode in lithium-ion batteries, deliver greatly enhanced cyclability and rate capacity compared with pristine Fe2O3: a specific capacity of 356 mu Ah cm(-2) mu m(-1) (3560 mAh cm(-3) or similar to 1118 mAh g(-1)) obtained at a discharge current density of 50 mu A cm(-2) (similar to 0.17 C) with 88% retention after 100 cycles and 165 mu Ah cm(-2) mu m(-1) (1650 mAh cm(-3) or similar to 518 mAh g(-1)) obtained at a discharge current density of 1000 mu A cm(-2) (similar to 6.6 C) for 1000 cycles were achieved. Meanwhile an energy density of 294 mu Wh cm(-2) mu m(-1) (2.94 Wh cm(-3) or similar to 924 Wh kg(-1)) and power density of 584 mu W cm(-2) mu m(-1) (5.84 W cm(-3) or similar to 1834 W kg(-1)) were also obtained, which may make these thin film anodes promising as a power supply for micro- or even nanosized portable electronic devices.