Effect of crystallinity on capacity and cyclic stability of Na1.1V3O7.9 nanoplates as lithium-ion cathode materials

High-crystalline Na1.1V3O7.9 nanoplates were synthesized by a facile sol-gel reaction followed by calcination. The microstructure and crystallinity of the nanoplates were primarily determined by calcination temperature. The maximum crystallinity Na1.1V3O7.9 sample was calcined at 500 degrees C was calculated by XRD, and the DSC demonstrated that the amorphous transformation temperature begins at 550 degrees C. The XPS spectrum confirmed the presence of Na1.1V3O7.9 and consistent with the XRD test results. The SEM/TEM test illustrated the crystal particle growth of the Na1.1V3O7.9 nanoplates. Electrochemical results showed that the maximum crystallinity Na1.1V3O7.9 sample prepared at 500 degrees C exhibited the optimum performance when evaluated as a cathode material for lithium-ion batteries: the discharge capacity was maintained at 195 mAh g(-1) after 150 cycles at a current of 100 mA g(-1).