Poly Vinyl Alcohol-Based Sol-Gel Synthesis of V2O5 Nanoflakes as Positive Electrodes of Li-ion Batteries

This work shows a new method to synthesize V2O5 nanostructures by poly vinyl alcohol-based sol-gel method. The precursor NH4VO3 and polyvinyl alcohol is dissolved in a binary (ethanol/water) solvent to obtain a sol solution and heated until to obtain a homogeneous polymeric gel. During gel pyrrolysis in an electrical furnace, vanadium salt is calcined to V2O5. The prepared samples are investigated by SEM, TEM, XRD and TGA-DTA. By this method, uniform V2O5 nanoflakes with 37 nm average thickness can be synthesized. Electrochemical behaviors of V2O5 samples are also investigated in a 0.1M LiClO4 electrolyte solution prepared in the 1:1 (V/V) ethylene carbonate and dimethyl carbonate solvents by cyclic voltammetry. Finally, some selected V2O5 nanomaterials are used as positive electrode materials of Li-ion batteries. The obtained results shows the morphologies and the particles sizes of the cathodic materials can significantly change the redox kinetic rates and charge/discharge performance of the batteries. The Battery made with V2O5 nanoflakes shows the highest discharge capacity of 430 mAh g(-1) and 280 mAh g(-1) for cycles of 1 and 100 at a current density of 100 mA g(-1), respectively.