The hierarchical structure is an ideal nanostructure for conversion-type anodes with drastic volume expansion. Here, we demonstrate a tin-doping strategy for constructing Fe2O3 brushes, in which nanowires with exposed (001) facets are stacked into the hierarchical structure. Thanks to the tin-doping, the conductivity of the Sn-doped Fe2O3 has been improved greatly. Moreover, the volume changes of the Sn-doped Fe2O3 anodes can be limited to ~4% vertical expansion and ~13% horizontal expansion, thus resulting in high-rate performance and long-life stability due to the exposed (001) facet and the unique hierarchical structure. As a result, it delivers a high reversible lithium storage capacity of 580 mAh/g at a current density of 0.2C (0.2 A/g), and excellent rate performance of above 400 mAh/g even at a high current density of 2C (2 A/g) over 500 cycles, which is much higher than most of the reported transition metal oxide anodes. This doping strategy and the unique hierarchical structures bring inspiration for nanostructure design of functional materials in energy storage.

Graphite powders are exfoliated by Li + /Na + co-intercalation to obtain exfoliated graphite, and then the surfaces are modified with oxygen-containing functional groups by oxygen plasma etching to alter the chemical properties of surface. For advanced graphite anodes of lithium ions batteries, here finestructured SnO 2 FeO(OH) coatings are constructed on the oxidated surfaces of graphite by an electrostatic adsorption method. Electrochemical tests show that surface modified graphite has higher capacity and better rate performance than pristine graphite, and the specific discharge capacity is reached to 400 mAh g À1 at a current of 37.2 mA g À1 (0.1C), which is increased by 27.8% compared with the pristine graphite anode.