Enhanced lithium storage properties achieved by TiO2 reinforced 2D CuO clusters

CuO has been regarded as a promising anode material for rechargeable batteries for its high theoretical specific lithium capacity (670 mAh g−1), low cost, earth-abudance, etc. The rapid capacity decay over discharging/charging cycles aroused by dramatic volume change and loss of structural stability, however, has been a main challenge for CuO being used as an active anode. Herein, a unique 3D porous CuO microspherical structure assembled from 2D CuO nanosheets and further mechanically reinforced by sandwiched TiO2 nanospindles has been innovated for enhancing both the mechanical stability of the designed nanostructures and the lithium storage properties. Owing to the favorable lithiation processes and fruitful chemically-active sites contributed by the constitutional 2D nanostructures and the superior structural stability and increased solid lithium storage interfaces contributed by the TiO2 reinforcement phased, the 3D CuO/TiO2 nanomaterials presented high reversible specific capacity, improved cycling performance, and good rate capability. This work, therefore, sheds a light on designing high-performance 3D electrode nanomaterials from 2D constitutional nanostructures with improved structural stability over cycles. An unprecedented 3D flower-like CuO/TiO2 composite (3D FCT), for which TiO2 nanospindles are embedded inside the porous flower-like structures stacked from 2D CuO nanosheets, was fabricated through a facile hydrothermal method. Compared with pure CuO, the 3D FCT exhibit greatly improved cycling performance at high current density of 2 A g−1. [Display omitted] •A unique 3D flower-like CuO/TiO2 composite (3D FCT) was fabricated from 2D CuO nanosheets and mechanically reinforced by TiO2 nanospindles.•3D FCT demonstrates remarkable electrochemical performance with high reversible capacity and cycle stability as well as capability.•3D FCT holds the favorable lithiation processes and fruitful chemically-active sites.