NOVELTY - Electrochemical cell comprises housing having disposed within it, electrolyte and multi-layer article at least partially immersed in the electrolyte, where multi-layer article comprises first metallic current collector, first electrode material in electrically conductive contact with first metallic current collector, second electrode material in ionically conductive contact with first electrode material, porous separator disposed between and contacting first and second electrode materials, and second metallic current collector in electrically conductive contact with second electrode material.    USE - The electrochemical cell is used as lithium-ion battery which is useful in e.g. consumer electronics, power tool and hybrid electric vehicles.    ADVANTAGE - The electrochemical cell utilizes multi-layer article to improve compatibility, to enhance or reduce wettability and to protect the surface from chemical attack, while retaining the porosity of the nanoweb structure.    DETAILED DESCRIPTION - Electrochemical cell comprises a housing having disposed within it, an electrolyte and a multi-layer article at least partially immersed in the electrolyte, where: the multi-layer article comprises a first metallic current collector, a first electrode material in electrically conductive contact with the first metallic current collector, a second electrode material in ionically conductive contact with the first electrode material, a porous separator disposed between and contacting the first and second electrode materials, and a second metallic current collector in electrically conductive contact with the second electrode material; the porous separator comprises a nanoweb comprising nanofibers of aromatic polyimide; and the nanoweb has a free surface at least a portion of which comprises a secondary amide comprising a functional group containing a hydrocarbon radical.    DESCRIPTION OF DRAWING(S) - The figure shows a multi-layer article.    Porous nanoweb separator (21)    Negative electrode (22)    Positive electrode (23)    Non-porous conductive metallic foil (24a, 24b)