Abstract: An electrochemical cell, includes a positive electrode and a negative electrode arranged face to face in the cell body, and a stack of electrolyte layers interposed between the positive electrode and the negative electrode. The stack of electrolyte layers comprises a first layer of solid electrolyte arranged at one end of the positive electrode, a second layer of solid electrolyte arranged at one end of the negative electrode, a composite powder layer interposed between the first layer and the second layer, the composite powder layer comprising an electrolyte powder and an electroactive material powder serving as a reference electrode for the electrochemical cell.

Abstract: The invention relates to a process for the preparation of sodium-based solid compounds, such as sodium-based solid alloys and sodium-based crystalline phases by ball-milling using metallic sodium as starting material. The invention also relates to some sodium-based crystalline P?2-phases and to Na-based vanadium phosphates phases (Na(3+y)V2(PO4)3) with 0<y?3 and Na-based vanadium fluorophosphates phases (Na(3+z)V2(PO4)2F3) with 0<z?3, in particular Na4V2(PO4)2F3, obtained by such a process and to their use, as active material for positive electrode, in a Na-ion battery.

Abstract: The present invention relates to a method for producing a positive electrode material comprising at least one Na-based solid crystalline phase selected in the group consisting of Na-based crystalline P?2-phases, Na-based solid crystalline phases of formula Na(3+x)V2(PO4)3 with 0<x?3 and Na-based solid crystalline phases of formula Na(3+y)V2(PO4)2F3 with 0<y?3, for a battery using sodium ions as electrochemical vector, said method using a ball milling process involving Na3P as starting material.

Abstract: The invention relates to a process for the preparation of sodium-based solid compounds, such as sodium-based solid alloys and sodium-based crystalline phases by ball-milling using metallic sodium as starting material. The invention also relates to some sodium-based crystalline P?2-phases and to Na-based vanadium phosphates phases (Na(3+y)V2(PO4)3) with 0<y?3 and Na-based vanadium fluorophosphates phases (Na(3+z)V2(PO4)2F3) with 0<z?3, in particular Na4V2(PO4)2F3, obtained by such a process and to their use, as active material for positive electrode, in a Na-ion battery.