Bi-ionic oxide bronzes of the A(x)BO(y) type (A = Na, Ca, Na-Ca, Sr, Na-Sr; B = V) were synthesized by solid state method. The values of partial electronic conductivity in the zNa(0.33)V(2)O(5)-(1-z)Ca(Sr)(0.165)V2O5 systems and ionic reversibility at the zNa(0.33)V(2)O(5)-(1-z) Sr0.165V2O5/Na3Zr2Si2PO12 interface were determined as functions of Na0.33V2O5 content. It has been found that the ion substitution process Sr2+ double left right arrow 2Na(+) occurs at the Sr0.165V2O5/Na+-SE interface. (C) 2004 Elsevier B.V All rights reserved.