TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The monomer unit of the first aqueous binder comprises at least one of a diene-based monomer unit, an acryl-based monomer unit, a fluorine-based monomer unit, or a silicon-based monomer unit, preferably at least one of a butadiene monomer unit, an isoprene monomer unit, an acrylate ester monomer unit, a methacrylate ester monomer unit, a vinylidenefluoride monomer unit, a tetrafluoroethylene monomer unit, a hexafluoropropylene monomer unit, or a siloxane monomer unit. The first aqueous binder: comprises a copolymer of the vinylidenefluoride based monomer and at least one monomer of tetrafluoroethylene or hexafluoropropylene, preferably a vinylidenefluoride-hexafluoropropylene copolymer; and further comprises an olefin-based monomer comprising ethylene, propylene, butene, butadiene, isoprene, or pentene, and a hydrophilic group comprising a carboxylic acid group, a hydroxyl group or a sulfonic acid group. The second aqueous binder is different from the first aqueous binder. The second aqueous binder comprises at least one of styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, acryl rubber, butyl rubber, fluorine rubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylenepropylene copolymer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, polystyrene, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, a polyester resin, an acryl resin, a phenol resin, an epoxy resin, polyvinylalcohol, hydroxypropylmethylcellulose, hydroxypropylcellulose or diacetylcellulose. The first aqueous binder and the second aqueous binder are present in the negative active material layer at a weight ratio of 0.1:1-10:1, preferably 0.25:1-10:1. The negative active material layer comprises 0.01-10 wt.%, preferably 0.01-5 wt.% of the first aqueous binder. The polymer layer comprises two layers, where each polymer layer is on opposite surfaces of the base material layer. The base material layer is a porous film containing a poly olefin material. The non-aqueous binder of the polymer layer comprises at least one of polyethylene, polypropylene, polyisobutylene, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl acetate, polyvinylalcohol, polyvinylisobutylether, polyacrylonitrile, polymethacrylonitrile, methyl polymethacrylate, methyl polyacrylate, ethyl polymethacrylate, allyl acetate, polystyrene, polybutadiene, polyisoprene, polyoxymethylene, polyoxyethylene, polycyclothioether, polydimethylsiloxane, polylactone, polyethyleneterephthalate, polycarbonate, nylon-6, nylon-66, poly-meta-phenyleneisophthalamide, poly-para-phenyleneterephthalamide, or polypyromellitimide. The polymer layer has a thickness of 0.1-10 mu m. The positive electrode comprises: a binder containing a monomer unit identical to the monomer unit of the first aqueous binder of the negative electrode; a binder identical to the non-aqueous binder of the separator; or a binder identical to the first aqueous binder of the negative electrode.