Composite plastic film material, preparation method thereof, battery and electric device

The invention relates to a composite plastic film material and a preparation method thereof, a battery and an electric device. The composite plastic film material comprises a first plastic film layer, a functional film layer and a second plastic film layer which are sequentially stacked, the functional film layer comprises a composite metal layer, the components of the composite metal layer comprise a nickel element and an iron element, and the mass ratio K1% of the nickel element in the composite metal layer meets the condition that K1% is larger than or equal to 50%.