Three-dimensional dendritic silicon negative electrode material and preparation method

The invention relates to the technical field of silicon negative electrode materials, and discloses a three-dimensional dendritic silicon negative electrode material and a preparation method. Nano-silicon particles are fine particles with slit openings, a volume change of a silicon material is only generated in single nano-particle in entry and exit processes of lithium ions, and the volume change is buffered and counteracted by internal cracks. The whole electrode plate prepared from the silicon material does not generate obvious volume expansion. The problem of violent volume expansion of the silicon material as the negative electrode material of a lithium battery in lithium extraction and insertion processes is effectively solved. The preparation method comprises the steps of dispersing the nano-silicon particles through a dispersing agent; and then carrying out snap freezing through liquid nitrogen, carrying out quick heating through microwaves and making the nano-silicon particles crack to form the silicon particles with three-dimensional dendritic cracks.