Electrochemical device and electronic device

The invention provides an electrochemical device and an electronic device, the electrochemical device comprises a positive electrode plate, a negative electrode plate and an electrolyte, the negative electrode plate comprises a negative electrode current collector and a negative electrode material layer, the negative electrode material layer comprises a silicon-based composite material, the silicon-based composite material comprises silicon-based particles, the strength of the negative electrode current collector is A MPa, and the strength of the negative electrode current collector is A MPa; the difference value between the maximum value and the minimum value of the relative percentage content of silicon atoms in the silicon-based particles is B%, the mass content of the silicon element in the negative electrode material layer is C%, and the condition that A, B and C are cooperatively adjusted to meet the condition is met, so that the obtained lithium ion battery has good cycle performance and expansion perf