Effect of Major Impurity in the Vanadium‐Rich Solution on the Growth of NaV₂O₅ Crystals under Hydrothermal Conditions

NaV 2 O 5 is a promising cathode material for ion batteries with high capacity and good cycle performance. The high concentration of vanadium and low impurity in vanadium‐rich solution makes it possible to be used as raw material for vanadium product preparation. Vanadium solution containing impurity was prepared to investigate its influence mechanism on NaV 2 O 5 crystal precipitation. The influence of four major impurity elements on the precipitation of NaV 2 O 5 following the order of P > Al > Si > Fe. With the increase of impurity concentrations, vanadium conversion rate and V content of the precipitates decreased to varying degrees, while impurity content increased. When concentrations of Fe, Al and Si were high, the resulting precipitate was still NaV 2 O 5 , but the crystal structure changed. The AlOH and SiOH hider the condensation between VOH and broke the rod into irregular flakes and blocks. As P concentration gradually increased, the precipitates changed from NaV 2 O 5 to VO 2 (H 2 O) 0.5 and then to Na 3 .053((V 5 O 9 )(PO 4 )2(OH)0.1(H 2 O)8, meanwhile, the morphologies changed from rod to plate, then to cross‐like, and finally to cube. Revealing the influence of impurity in vanadium‐rich solution on the growth of NaV 2 O 5 crystal is conducive to the popularization of the process.