TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Metal: The alkali metal is sodium or potassium. Preferred Composition: Secondary ceramic particles formed by sintering or re-crystallizing primary ceramic particles are combined with the binder. The secondary ceramic particles comprise particle groups having a cluster shape or layered particle group. The ceramic material comprises alumina, zirconium oxide and/or titanium oxide. The ceramic material is chosen from insulative nitrides, hydroxide, and ketones of zirconium, aluminum, silicon and/or titanium. The ceramic material and binder are mixed in weight ratio of 95:5-80:20. The anode and cathode comprise anode and cathode active materials which intercalate and de-intercalate lithium ions. The anode active material is chosen from 13 claimed materials, such as lithium-manganese-rare earth element containing material of formula: LixMn1-yMyA2, where x is 0.9-1.1, y is 0-0.5, M is element chosen from magnesium, aluminum, cobalt, potassium, sodium, calcium, silicon, titanium, tin, vanadium, germanium, gallium, boron, arsenic, zirconium, manganese, chromium, iron, strontium, and rare earth elements, and A is chosen from oxygen, fluorine, sulfur and phosphorus. The cathode active material is chosen from crystallized carbon, amorphous carbon, carbon composite, carbon fiber, lithium metal and/or lithium alloy.    TECHNOLOGY FOCUS - POLYMERS - Preferred Rubber: The acrylic rubber structure is formed by a cross-linking reaction between a polymer or copolymer of an acrylic main monomer and a cross-linkable comonomer. The acrylic main monomer is methyl methacrylate. The cross-linkable comonomer is chosen from 2-ethylhexyl acrylate, octyl acrylate and/or acrylonitrile. Preferred Composition: The polymer or copolymer of the acrylic main monomer and the cross-linkable comonomer are mixed in weight ratio of 90:10-60:40, preferably 70:30. A portion of the side chain of the polymer or copolymer of the acrylic main monomer is capped with an alkali metal. The separator further comprises a separate polyolefin-based resin film. The polyolefin-based resin film is chosen from polyethylene single-layered film, polypropylene single-layered film and polypropylene-polyethylene-polypropylene multilayered film.