Methods of making and using an electrochemical cell comprising an interlayer

A process for making an electrochemical stack, comprising

• providing a solid-state electrolyte separator;
• providing an interlayer on one side of the solid-state separator;
• providing a negative electrode current collector (NECC), wherein the interlayer is between the NECC and the solid-state separator;
• and
• applying pressure of at least 10 pounds per square inch (psi) to the solid-state separator, interlayer, and NECC.

An electrochemical cell comprising:

• a negative electrode current collector (NECC);
• a solid-state electrolyte separator;
• an interlayer between the negative electrode and the solid-state separator;
• wherein the interlayer comprises at least one member selected from the group consisting of zinc (Zn), tin (Sn), magnesium (Mg), silver (Ag), aluminum (Al), indium (In), bismuth (Bi), a lithium alloy thereof, oxides thereof, hydroxides thereof, peroxides thereof, and combinations thereof,
• a positive electrode;
• and
• a positive electrode current collector,
• wherein the electrochemical cell is pressurized at a pressure lower than 300 psi.