Synthesis and characterization of novel hierarchical starfish-like vanadium oxide and their electrochemical performance

• A novel hierarchical starfish-like vanadium oxide are synthesized by a simple hydrothermal method.
• The functional V2O5 sol plays a crucial role for formation hierarchical starfish-like structure.
• Starfish-like vanadium oxide grown along the (1 1 0) plane and four oblique sheets grown on the flanking of (1 1 0) plane, respectively.
• Hierarchical starfish-like V2O5 cathode materials can deliver discharge capacity of approximately 163 mA h g−1 at high current density of 1000 mA g−1 (5C) after 50 cycles

ABSTRACTA novel hierarchical starfish-like vanadium oxide is synthesized by a simple and direct hydrothermal method using a functional V2O5 sol as a vanadium source. The formation mechanism of hierarchical starfish-like structure is discussed. Results demonstrate that the functional V2O5 sol plays a crucial role in the formation of a hierarchical starfish-like structure. Starfish-like vanadium oxide is composed of single crystals of a metastable VO2 (B) phase that grow along the (1 1 0) plane and four oblique sheets growing on the flanks of the (1 1 0) plane. The starfish-like structure can be preserved and undergoes phase transition to the orthorhombic V2O5 phase when calcined at 350 °C. Hierarchical starfish-like V2O5 displays higher electrochemical performance than pristine V2O5 powder as a cathode material for LIBs. This improved performance could be attributed to the shortened diffusion path of lithium ions in the former; a large electrode/electrolyte contact area resulting from the unique hierarchical starfish-like structure composed of nanosheets also offers better electrolyte wetting and alleviates the structural degradation upon cycling. The hierarchical starfish-like V2O5 can deliver a discharge capacity of approximately 163 mA h g−1 at a high current density of 1000 mA g−1 (5C) even after 50 cycles.