Chemical Sodiation of V 2 O 5 by Na 2 S

Chemical sodiation of V 2 O 5 at low temperatures allows to synthesize Na x V 2 O 5 with 0 ≤ x ≤ 1, while classic high temperature syntheses yield in either x ≤ 0.02 (α‐phase) or 0.7 ≤ x (α′‐phase), or other phases (β‐phase, δ‐phase) or mixtures thereof. A suspension of V 2 O 5 in acetonitrile and Na 2 S as sodiation agent were used. The maximum amount of sodiation was obtained by using an excess of Na 2 S, refluxing the acetonitrile during the reaction, and precedent ball milling of the V 2 O 5 . If only low amounts of Na 2 S were used as starting material, a mixture of fractions of Na x V 2 O 5 with different values of x was obtained. All these fractions belong to the α‐ or α′‐phase, space group Pmmn .