Crystal structure and electronic properties of the Ag2V4O11insertion electrode

The crystal structure and electronic properties of Ag2V4O11 have been explored by means of x-ray four-circle diffraction and through measurements of electrical resistivity, thermoelectric power, magnetization, and electron paramagnetic resonance. The crystal data for the nearly stoichiometric compound show a monoclinic structure with space group C2/m; a = 15.480(3) Å, b = 3.582(1) Å, c = 9.537(2) Å, β = 128.741(9)°, and Z = 2. The structure at 293 K determined with residual factors of R = 0.055 and Rw = 0.051 is described as the stacking of layers formed by sharing edges and corners of distorted VO6 octahedra. The transport mechanism of 3d electrons donated by the slight deficiency of oxygen atoms is understood as a small-polaron conduction in the localized states of band tails.