General synthesis of metal oxide hollow core–shell microspheres as anode materials for lithium-ion batteries and as adsorbents for wastewater treatment

Hollow core–shell structures have many advantages, but their synthesis remains challenging. In this report, we demonstrate a general method for the preparation of a series of metal oxide hollow core–shell microspheres, including Co₃O₄, NiO and Mn₂O₃. The hollow core–shell microspheres were prepared via a coordination precipitation route followed by a calcination process. The morphology and microstructures of the metal oxide hollow core–shell microspheres could be controlled by optimizing the experimental conditions. A possible formation mechanism of the hollow core–shell structure was proposed. As anode materials for lithium ion cells, the Co₃O₄ hollow core–shell microspheres exhibited superior Li⁺ storage properties. When applied as adsorbents in water treatment, the NiO hollow core–shell microspheres showed an excellent ability to remove organic pollutants.