Patent ID: 6451487
Filing Date: 2002-09-17
Classification: H01M,Y02E,Y02P

Abstract:
A composite electrode for an electrochemical cell, wherein said electrochemical cell comprises the composite electrode, a second electrode and one or more electrolyte acting as a separator, wherein the electrolyte is disposed between the composite electrode and the second electrode, said composite electrode comprising a current collector, dispersed particles of electrochemical active material, a first additive of electronic conduction and two or more solid electrolytes, a first solid electrolyte which is vitreous and mineral, and a second solid electrolyte which is an organic polymer electrolyte, wherein the vitreous mineral electrolyte wets part of the surface of the active material dispersed in the composite electrode, an additive of conduction, which is present therein, and the current collector so as to form a porous mineral sub-assembly, said surface having been wetted in part, thus being protected by an impervious mineral phase, the second solid electrolyte being in intimate contact with the porous mineral sub-assembly so as to ensure ionic exchanges within the composite electrode and with the other components of the cell, said second solid electrolyte additionally acting as deformable binder for the combination comprising the composite electrode, its collector and the separator of the cell, said composite electrode thereby ensuring zones where at least part of the exchange surfaces between solid phases and the vitreous mineral electrolyte is made non-accessible to the components of the organic polymer electrolyte and to contaminants which may originate from the other components of the electrochemical cell, said composite electrode therefore being less susceptible to be subject to the formation of passivation or degradation films, thereby ensuring electrical contacts within the composite electrode, in spite of adverse conditions of temperature, voltage or cycling within the cell.