Hierarchical Porous CoxFe3-xO4 Nanocubes Obtained by Calcining Prussian Blue Analogous as Anode for Lithium-ion Batteries

Mixed transitional oxides have attracted improving attention as anode materials for lithium-ion batteries (LIBs) because of their enhanced lithium storage properties than single metal oxides. In this work, porous CoxFe3-xO4 nanocubes have successfully constructed through a facile two-step method by using room temperature synthesized cobalt-iron-based Prussian blue analogue (PBA) as precursor. The CoxFe3-xO4 nanocubes fabricated at different temperature possessed diverse surface areas and pore volume. When applied as LIBs anode material, the CoxFe3-xO4 nanocubes synthesized at 700 °C delivered the highest reversible capacity of about 1601 mAh g-1 at 100 mA g-1 after 60 cycles and exhibited best rate capability with a capacity of 950 mAh g-1 at the high current density of 5000 mA g-1. The enhanced electrochemical performance could attributed to the structural feature of large amounts of nanopores within the nanocubes, which could provide large space to buffer volume expansion during the Li+ insertion/extraction processeses and improve structure stability.