Synthesis of Nb Doped Vanadium Oxide Bronzes and Properties of Intercalation and Ion Exchange

摘要

The layer structure phase, Li_xV_(3-y)Nb_yO_8 and the tunnel structure phase, #beta#-M_xM_(2-y)Nb_yO_5 (M = Ag, Li, Ca) were synthesized by molten salts electrolysis in the electrolytic bath of V_2O_5-Li_2CO_3-Nb_2O_5 melts, V_2O_5-Ag_2O-Nb_2O_5-AgCl melts and so on. The effect of the addition of niobium to vanadium bronzes on electrochemical properties was studied. The layer phase represents a higher electrical conductivity and a higher reversibility for Li~+ ions electrochemical insertion in 1mol dm~(-3) LiClO_4/PC (propylene carbonate) electrolytes, compared with no niobium-doped Li_xV_3O_8 phase. The ion-exchange reactions with proton (H~+) and potassium catins (K~+) were examined at 25 deg C by the batch method. It was found that the Li~+ between layers of Li_xV_(3-y)Nb_yO_8 was able to exchange easily with H~+ and K~+ in aqueous solution.