Nanostructured V₂O₅ arrays on metal substrate as binder free cathode materials for sodium-ion batteries

Highlights: • V₂O₅ arrays with different morphologies are constructed on titanium foil for the first time. • The morphologies of V₂O₅ are time-dependent. • The V₂O₅ arrays are charactered as binder free cathode materials for sodium battery. • The sodium storage performance of V₂O₅ array is morphology-dependent. • EIS and Ex-situ SEM were performed to study the mechanism of the performance difference. - Abstract: Herein, we report the synthesis of orthorhombic V₂O₅ array with hair-like, javelin-like and wall-like structures on conductive titanium foil by a simple time-dependent hydrothermal method. The morphological evolution process of this product has been investigated in detail. The affection of morphology on sodium storage performance is probed. Benefitting from the unique javelin-like structure, the orthorhombic V₂O₅ array shows a prolonged cycle ability and high rate ability. Ex-Situ scanning electron microscope (SEM) and electrochemical impedance spectroscopy (EIS) are performed to clarify the mechanism.