Constructing hierarchical MnO2/Co3O4 heterostructure hollow spheres for high-performance Li-Ion batteries

Fabricating electrode with hierarchical heterostructure is an effective method to incorporate the merits of different active materials into an electrode with desired electrochemical performance. However, heterostructure electrodes constructed layer by layer may increase the ion diffusion distances inadvertently when used for alkali metal ion batteries, though the synergistic effects of the components are exhibited. In this work, Co3O4 nanocrystallines (about 5 nm) anchor on ultrathin MnO2 nanosheets, which assemble hierarchical heterostructure hollow spheres (named as MnO2/Co3O4). When used as LIBs anode, the different dimensions of the components in MnO2/Co3O4 make them accessible for the electrolyte synchronously, without enlarging the ion diffusion distance. Moreover, the unique hierarchical hollow structure mitigates the internal mechanical stress brought by the volume variations upon cycling, preventing the electrode collapse. Therefore, the as-prepared MnO2/Co3O4 electrode not only delivers a high reversible capacity of 1209.0 mAh g−1 at 0.4 A g −1 over 300 cycles, but also exhibits long cyclic stability (a capacity of 581.8 mAh g−1 at 2.0 A g−1 after 1100 cycles). This work could provide new insight into heterostructure materials for batteries. [Display omitted] •Hierarchical MnO2/Co3O4 heterostructure hollow spheres are fabricated.•Co3O4 nano-crystallines (about 5 nm)anchor on ultrathin MnO2 nanosheets.•Dimension differences favor the contact between active materials and electrolyte.•A capacity of 581.8 mAh g−1 at 2.0 A g−1 over 1100 cycles is achieved by MnO2/Co3O4.