Lithium supplementing composite layer and preparation method thereof, lithium supplementing method, pre-lithiated negative pole piece, secondary battery and electronic device

Abstract

The invention provides a lithium supplement composite layer and a preparation method thereof, a lithium supplement method, a pre-lithiated negative pole piece, a secondary battery and an electronic device, the lithium supplement composite layer comprises an interface layer and a lithium supplement layer which are laminated, the interface layer comprises interface particles and a binder, the interface particles comprise a lithium intercalation material and / or a conductive agent, and the binder comprises a lithium intercalation material and / or a conductive agent. The lithium intercalation material is selected from at least one of artificial graphite, natural graphite, hard carbon, a silicon-carbon material, a silicon-oxygen material, lithium titanate, tin and a tin-copper alloy, and the conductive agent is selected from at least one of conductive carbon black, carbon fiber, graphene and a carbon nanotube; the binder is selected from at least one of polytetrafluoroethylene, an ethylene-tetrafluoroethylene copolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluoride and polyoxyethylene; the lithium supplementing layer comprises lithium metal and / or lithium alloy. The lithium supplement composite layer meets the above characteristics, lithium supplement is carried out on the negative pole piece, the first coulombic efficiency of the secondary battery can be improved, the cycle capacity attenuation is reduced, and the energy density of the secondary battery is improved.

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