Electrochemical Properties of Na0.66V4O10 Nanostructures as Cathode Material in Rechargeable Batteries for Energy Storage Applications

We report the electrochemical performance of nanostructures of Na0.66V4O10 as cathode material for rechargeable batteries. The Rietveld refinement of room-temperature X-ray diffraction pattern shows the monoclinic phase with C2/m space group. The cyclic voltammetry curves of prepared half-cells exhibit redox peaks at 3.1 and 2.6 V, which are due to two-phase transition reaction between V5+/(4+) and can be assigned to the single-step deintercalation/intercalation of Na ion. We observe a good cycling stability with specific discharge capacity (measured vs Na+/Na) between 80 (+/- 2) and 30 (+/- 2) mAh at current densities of 3 and 50 mA g(-1), respectively. The electrochemical performance of Na(0.66)V(4)O(10 )electrode was also tested with Li anode, which showed higher capacity but decayed faster than Na. Using density functional theory, we calculate the Na vacancy formation energies: 3.37 eV in the bulk of the material and 2.52 eV on the (100) surface, which underlines the importance of nanostructures.