High-purity, low-Cl V2O5 via the gaseous hydrolysis of VOCl3 in a fluidized bed

Present-day all-vanadium redox flow batteries(VRFBs)generally require high purity vanadium oxide as a raw ingredient.The chlorination procedure presents distinct technical advantages with regard to preparing high purity vanadium pentoxide(V2O5)using vanadium oxytrichloride(VOCl3)as a highly pure intermediate.To efficiently prepare high purity V2Os from VOCl3,a single-step fluidized bed chemical vapor deposition(FBCVD)method was explored in the present work.Based on thermodynamic analyses,the direct and complete conversion of VOCl3 to V2O5 is difficult,and may result in a small amount of residual Cl in the product.Consequently,the effects of temperature and the H2O/VOCl3 molar ratio on the quantity of residual Cl were assessed.The Cl concentration was found to decrease with increasing temperature or increasing H2O/VOCl3 molar ratios.Additionally,Cl was determined to be present only in the form of Cl-V bonds,while Cl-H and Cl-Cl bonds were not detected in a V2O5 product made at 200℃with a H2O/VOCl3 molar ratio of 18.A Cl concentration of less than 0.05 wt%was obtained under the optimal synthesis conditions,demonstrating that the FBCVD method is a viable means of preparing high purity V2O5 via the gaseous hydrolysis of VOCl3.