Polyimide web separator for use in an electrochemical cell

A multi-layer article for an electrochemical cell, the multi-layer article comprising:

• (a) a first electrode;
• (b) a second electrode;
• and
• (c) a separator disposed between and in contact with the first electrode and the second electrode, the separator comprising:
• (i) a web comprising fibers of a polyimide;
• and
• (ii) a protective region disposed between the web and at least one electrode wherein the protective region impedes electrochemical polyimide reduction.

An electrochemical cell comprising:

• (a) an electrolyte;
• (b) a multi-layer article, the multi-layer article comprising a first electrode, a second electrode in ionically conductive contact with the first electrode, and a separator disposed between and in contact with the first electrode and the second electrode, the separator comprising:
• (i) a web comprising fibers of a polyimide;
• and
• (ii) a protective region disposed between the web and at least one electrode wherein the protective region impedes electrochemical polyimide reduction;
• (c) a first current collector in electrically conductive contact with the first electrode;
• and
• (d) a second current collector in electrically conductive contact with the second electrode.