Synthesis and Electrochemical Properties of Flower-like Na-doped V6O13 Cathode Materials for Li-ion Batteries

Flower-like NaxV6O13 samples (x= 0 similar to 0.535) are fabricated via a typical hydrothermal method followed by annealed process at 350 degrees C for 1h in argon atmosphere. The phase structure, chemical composition, morphology and element valence of prepared samples are characterized by XRD, XPS, FESEM and EDS. The electrochemical properties of prepared samples are measured by CV, EIS and charge-discharge analyses. These results demonstrates that the enhancement of electrochemical reversibility in Na-doped V6O13 cathode materials are attributed to its high total conductivity, low charge transfer resistance and better electrochemical reversibility. In addition, both crystal domain size and the lithium diffusion coefficient of the Na-doped V6O13 samples are influenced by the added amount of NaNO3. When the doped molar ratio of Na+ to V6O13 is 0.321/1, the product presents hierarchical flower-like microsphere morphologies, which is assembled by interconnected nanorods. It demonstrates the best electrochemical performance with initial discharge capacity of 422.47mA.h/g. After 100cycles, the discharge capacity and capacity retention of Na0.321V6O13 are 215.30mA.h/g and 51% respectively.