Low-expansion silicon-carbon negative electrode material and preparation method thereof, negative electrode plate and button cell

The invention discloses a low-expansion silicon-carbon negative electrode material and a preparation method thereof, a negative electrode plate and a button battery, belongs to the technical field of secondary batteries, and particularly relates to two types of negative electrode materials (a silicon negative electrode structure 1 and a silicon negative electrode structure 2). Each of the silicon negative electrode structure 1 and the silicon negative electrode structure 2 comprises four components: an internal matrix material, an internal matrix surrounding silicon component, an internal silicon carbide component and a surface coating layer. In the silicon negative electrode structure 1, the silicon component is mainly coated on the surface of the silicon carbide component. In the silicon negative electrode structure 2, a silicon component and a silicon carbide component are dispersed in a matrix structure. The silicon negative electrode structure 1 is prepared through a gas phase process, and the silicon ne