Negative pole piece, secondary battery, battery module, battery pack and electric device

The invention discloses a negative pole piece, a secondary battery, a battery module, a battery pack and an electric device. The negative pole piece comprises a negative current collector and active substance layers arranged on at least one surface of the negative current collector, the active substance layers comprise a first active substance layer and a second active substance layer arranged on the surface of the first active substance layer, the first active substance layer comprises a first active material, and the second active substance layer comprises a second active material. The first active material layer includes a first active material, the second active material layer includes a second active material, and the active material layer satisfies: alpha * CW2 < = CW1, where alpha is an interlayer spacing relative factor, and 1 < = alpha < = 1.12. The rate capability and the energy density of the secondary battery obtained by using the negative pole piece disclosed by the invention can be well improved