Electrochemical Na-Deintercalation from NaVO2

This paper describes the preparation of NaxVO2 phases by means of electrochemical deintercalation. The curves V = f( x) show that the process is reversible up to x = 0.5 and they indicate the presence of multiple single phase domains in the range 1 < x < 0.5. Two single phases have been successfully isolated for Na1/2VO2 and Na2/3VO2 compositions; we report here the first X-ray powder diffraction measurements of these phases. They present a O'3-type monoclinic distortion of the O3 rhombohedral phase observed for Na1VO2. The evolution of cell parameters with sodium deintercalation is comparable with other A(x)MO(2) layered oxides. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3555102] All rights reserved.