Controllable synthesis of nanosheet-induced 3D hierarchical Zn₂(OH)₃VO₃ with gradually enhanced electrochemical performance

Three-dimensional hierarchical mixed transition metal compounds (MTMCs) assembled by two-dimensional (2D) nanosheets hold great potential as high-performance electrode materials. Despite the abundant reserve and multi-type valence states of vanadium (V), constructing V-based MTMCs with 2D subunits still remains great challenges. Here, we reported a facile one-step hydrothermal approach to fabricate hierarchical flower-like Zn₂(OH)₃VO₃ with highly uniform morphology and diameter, which are assembled by 2D nanosheets with average thickness of 20 nm. Appropriate amount of NH₃•H₂O and adequate reaction time are critical for obtaining the hierarchical Zn₂(OH)₃VO₃ microflowers with high crystalline. Combining the large active surface area of 2D nanosheets, porous structure of 3D hierarchical microflowers, and multiple reaction mechanism of Zn₂(OH)₃VO₃, the as-prepared hierarchical Zn₂(OH)₃VO₃ manifests excellent lithium storage properties in term of stable cycling performance up to 3000 cycles and good rate capability. Moreover, systematical analyzes based on cyclic voltammetry, electrochemical impedance spectroscopy, and ex-situ XRD indicate that newly emerged redox, accelerated kinetics, and gradually enhanced utilization of active sites originating from the electrode activation should account for the gradually increased capacity upon cycling.