The facile synthesis of hierarchical porous flower-like NiCo ₂O₄ with superior lithium storage properties

In this work, we demonstrate the facile fabrication of 3-dimensional (3D) hierarchical porous flower-like NiCo₂O₄ and its application as an anode material in high-performance lithium ion batteries (LIBs). The uniform flower-like NiCo₂O₄ is built from porous nanoplates with thicknesses of approximately 25 nm. A detailed investigation reveals that PVP plays an important role, not only in controlling the formation of the delicate hierarchical flower-like structure, but also in creating the uniform pores of each nanoplate. Furthermore, a possible formation mechanism for this unique structure is proposed based on the experimental results. As a virtue of its beneficial structural features, the as-prepared NiCo₂O₄ exhibits an enhanced lithium storage capacity and excellent cycling stability (∼939 mA h g^-1 at 100 mA g ^-1 after 60 cycles). This remarkable electrochemical performance can be attributed to the hierarchical structure and sufficient void space within the surface of the nanoplates, which effectively increases the contact area between the active materials and the electrolyte, reducing the Li⁺ diffusion pathway and buffering the volume change during cycling.