TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The metal cations include a cation of at least one of manganese, cobalt, nickel, or iron.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The microporous polymer separator comprises: a membrane having the polymer with the chelating agent tethered to it and incorporated into the membrane structure; or a membrane having the polymer with the chelating agent tethered to it and applied, as a layer, to one surface of the membrane or more than one surface of the membrane.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The chelating agent is a crown ether, podand, lariat ether, calixarene, and/or calixcrown. The crown ether is a cryptand. The chelating agent is: a crown ether comprising a 15-crown-5, 18-crown-6, or 21-crown-7; or a cryptand comprising cryptand (2.2.2), cryptand(2.2.1), or cryptand(2.1.1), preferably 18-crown-6, cryptand (2.2.2), cryptand(2.2.1), or cryptand(2.1.1). The crown ether is substituted with one of sulfur or nitrogen at at least one oxygen site of the crown ether. The chelating agent is not present in the lithium ion battery as free molecules.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The polymer to which the chelating agent is tethered is polyethylene terephthalate, polyvinylidene fluoride, polyamide, polyurethane, polycarbonate, polyester, polyetheretherketone, polyethersulfone, polyimide, polyamide-imide, polyether, polyoxymethylene, polybutylene terephthalate, polyethylene naphthenate, polybutene, polyolefin, polyolefin copolymer, acrylonitrile butadiene styrene copolymer, polystyrene copolymer, polymethylmethacrylate, PVC, polysiloxane polymer, polybenzimidazole, polybenzoxazole, polyphenylene, polyarylene ether ketone, polyperfluorocyclobutane, polytetrafluoroethylene, polyvinylidene fluoride copolymer, polyvinylidene fluoride terpolymer, polyvinylfluoride, liquid crystalline polymer, poly(hydroxybenzoic acid), polyaramide and/or polyphenylene oxide. Preferred Method: The polymer having the chelating agent tethered to it is applied to a surface of the positive electrode or to a surface of the negative electrode. The polymer having the chelating agent tethered to it is incorporated into the positive electrode or the negative electrode.