Composite negative electrode material and preparation method and application thereof

The invention provides a composite negative electrode material and a preparation method and application thereof. The composite negative electrode material comprises hard carbon primary particles and graphite secondary particles, and the hard carbon primary particles are located in internal gaps of the graphite secondary particles. The preparation method comprises the following steps: kneading graphite secondary particles and hard carbon primary particles to enable the hard carbon primary particles to enter internal gaps of the graphite secondary particles to obtain the composite negative electrode material. According to the invention, the small-particle hard carbon primary particle material is mixed with the graphite secondary particles, so that internal gaps of the secondary particles are filled with the small particles, and the compaction density of the material is improved; and after the structure of the mixed hard carbon material is adopted, electron conduction channels in the material can be increased, a