NOVELTY - Lithium ion battery (10) comprises: a positive electrode (14); a negative electrode (12); a microporous polymer separator (16) disposed between the negative electrode and the positive electrode; and a polymer having a chelating agent tethered to it, where the polymer is incorporated into the lithium ion battery such that the chelating agent complexes with metal cations in a manner sufficient to not affect movement of lithium ions across the microporous polymer separator during operation of the lithium ion battery.    USE - The lithium ion battery is useful in consumer electronics, automobiles, and aerospace industries.    ADVANTAGE - The lithium ion battery utilizes a polymer having a chelating agent that complexes with metal cations without affecting movement of lithium ions (claimed), thus reducing or preventing the poisoning of the negative electrode by transition metal cations (e.g. manganese ion or cobalt ion) that is present in the electrolyte solution and improving the life of the battery.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for making the lithium ion battery, comprising either: (a) tethering a chelating agent to a polymer, (b) applying the polymer having the chelating agent tethered to it to a surface of a membrane of a microporous polymer separator, to a surface of a negative electrode, and/or to a surface of a positive electrode, and (c) arranging the microporous polymer separator between the negative electrode and the positive electrode; or (a) as above per se, incorporating the polymer having the chelating agent tethered to it into a membrane of a microporous polymer separator, into a negative electrode, and/or into a positive electrode, and (c) as above per se.    DESCRIPTION OF DRAWING(S) - The figure shows a schematically view of the lithium ion battery during a discharging state.    Lithium ion battery (10)    Negative electrode (12)    Positive electrode (14)    Microporous polymer separator (16)    Load device (22)