Fabrication of nano/micro hierarchical Fe₂O₃/Ni micrometer-wire structure and characteristics for high rate Li rechargeable battery

The nano/micro hierarchical Fe2 O3 Ni micrometer wire, which is a low-cost material, as a negative electrode for Li-ion cells with the high specific capacity at high charge/discharge current rate, was fabricated. Nanocrystalline and mesoporous Fe2 O3 film was formed on nickel mesh, knitted of nickel micrometer wires, via pyrolytic transformation of FeO (OH)0.29 (N O3) 0.27 (C O3) 0.22 ,0.6 H2 O film, which was directly deposited on the entire surface of the nickel mesh by chemical bath deposition. The nestlike morphology with nanoflake of iron oxyhydroxide was maintained after the pyrolysis reaction into Fe2 O3. Moreover, each nanoflake was constructed by several nanometers particles. This specific hierarchical morphology not only provides ideal electrolyte, lithium ion paths, and electronic paths, but it also reduces both the required diffusion length in the active materials and the effective specific current density. The resultant Fe2 O3 negative electrode, which gives a high specific charge/discharge capacity 780 mAhg with good cycle performance even in a high charge/discharge current rate of 13 Ag, indicates the possibility for an energy storage device with high energy density at high power density.