Controlled synthesis of anisotropic hollow ZnCo₂O₄ octahedrons for high-performance lithium storage

Hollow micro-/nanostructures of metal oxides have attracted tremendous research attention in energy storage due to their unique structural advantages. Although fabrication of spherical hollow architectures have been intensively reported, rational design and facile synthesis of anisotropic hollow structures are still quite challenging, especially for those complex mixed metal oxides with well-controlled interior structures. Herein, through facile citrate-assisted hydrothermal synthesis and subsequent controlled annealing, well-defined octahedral ZnCo₂O₄ solid, hollow and yolk-shell micro-/nanostructures were constructed for the first time. When used as anode materials for lithium ion batteries (LIBs), the hollow ZnCo₂O₄ octahedron exhibits the best lithium storage properties, delivering high discharge capacities of 880 mA h g⁻¹ over 160 cycles at 0.2 A g⁻¹, and 650 mA h g⁻¹ over 300 cycles at 1 A g⁻¹. Moreover, it shows a superior high-rate performance with 60% of the specific capacity maintained even at a high current density of 5 A g⁻¹. These features render the hollow octahedral ZnCo₂O₄ micro-/nanostructure a promising anode for next generation LIBs.