A study of the efficient approach to introduce two Na ions into a NaVOPO4 matrix and an analysis of the electrochemical performance of NaVOPO4/Na2V(PO4)2

Abstract

In this work, we manufacture NaVOPO4 with the addition of one additional Na ion to enhance the stability and electrochemical formulation utilizing three ways, including sol gel-assisted hydrothermal, pure sol-gel, and solid state reaction methods. The sol-gel aided hydrothermal approach is the most effective way to add more Na ions to the NaVOPO4 matrix out of the three. Due to the presence of carbon content in high temperatures, the alterations of oxygen environment (O (1 &2) sites around the Na and V cause NaVOPO4/ Na2V(PO4)2 (NVP). The traces with high intensity at 17.99o indicates the tetragonal phase of Na2V(PO4)2 in NaVOPO4 and it is concreted by Raman analysis by peak shifting from 884 to 866 cm–1 . The character in Na2V(PO4)2 influences the Na ion intercalation process and yields the specific capacity in a three-electrode system is 0.83mAh/g at the scan rate of 10mV/s.