The invention discloses a
vanadium manganese sodium phosphate positive
electrode material with a
sodium-site high-entropy structure and a preparation method, and belongs to the technical field of
sodium ion batteries, the chemical general formula of the positive
electrode material is Na (4-x-y) MxNyVMn (PO4) 3, M is at least three of Li < + >, K < + >, Rb < + > and Cs < + >, and N is at least two of Be < 2 + >, Mg < 2 + >, Ca < 2 + >, Sr < 2 + > and Ba < 2 + >; according to the method, Na < + > / vacancy ordered and charge ordered structures formed by the
crystal during charging and discharging are inhibited through disordered distribution of multiple element atoms at sodium
ion sites, structural changes caused by Na < + > intercalation and deintercalation are reduced, meanwhile, the high-entropy elements occupying the sodium sites also play a role of supporting columns on the
crystal structure, and all the elements are beneficial to stabilizing the
crystal structure; on the other hand, due to the high-entropy elements, lattices are locally distorted, local disorder is caused, an
electronic band gap and a sodium
ion diffusion barrier can be reduced, the
conductivity and ion
diffusion kinetics of the material are improved, more importantly, Na (1)-O bonds are effectively weakened by the high-entropy elements at the sodium site, the electrochemical activity of sodium ions at the Na (1) site is activated, and the electrochemical activity of the sodium ions at the Na (1) site is improved.
Sodium ion
diffusion kinetics and specific capacity are promoted.