Abstract: An electrochromic device which comprises two conductive electrodes separated by a solid electrolyte and an electrochromic material capable of reversible electrochromic interaction with activating electrons and/or ions furnished to it by, or by it to, the rest of the device under the influence of an electrical potential applied across the electrodes, characterized in that the solid electrolyte in the device comprises:a) a matrix of optionally cross-linked main polymer chains, having side-chains linked to the main polymer chains, which side chains comprise polar groups,b) an ionized ammonium or alkali metal salt dissolved in the matrix and/or liquid, andc) an optional polar aprotic liquid dispersed in the matrix,and a process for the preparation thereof.

Abstract: AN electrochemical cell which comprises a conductive anode and cathode capable of mutual electrochemical reaction and separated by a solid electrolyte comprising:(a) a matrix of sheets of atoms, having side-chains linked to the sheets, which side chains comprise polar groups free from active hydrogen atoms,(b) a polar aprotic liquid dispersed in the matrix, and(c) a highly ionized ammonium or alkali metal salt dissolved in the matrix and/or liquid,a cathode therefor, the electrolyte per se, and processes for the preparation of the electrolyte and the cathode.