Biomimetic Straw‐Like Bundle Cobalt‐Doped Fe2O3 Electrodes towards Superior Lithium‐Ion Storage

Abstract Biomimetic straw‐like bundles of Co‐doped Fe 2 O 3 (SCF), with Co 2+ incorporated into the lattice of α‐Fe 2 O 3 , was fabricated through a cost‐effective hydrothermal process and used as the anode material for lithium‐ion batteries (LIBs). The SCF exhibited ultrahigh initial discharge specific capacity (1760.7 mA h −1 g −1 at 200 mA g −1 ) and cycling stability (with the capacity retention of 1268.3 mA h −1 g −1 after 350 cycles at 200 mA g −1 ). In addition, a superior rate capacity of 376.1 mA h −1 g −1 was obtained at a high current density of 4000 mA g −1 . The remarkable electrochemical lithium storage of SCF is attributed to the Co‐doping, which increases the unit cell volume and affects the whole structure. It makes the Li + insertion–extraction process more flexible. Meanwhile, the distinctive straw‐like bundle structure can accelerate Li ion diffusion and alleviate the huge volume expansion upon cycling.