Composite negative electrode material, preparation method thereof and battery

The invention relates to the technical field of batteries, in particular to a composite negative electrode material, a preparation method thereof and a battery. The provided composite negative electrode material comprises a carbon-based material and a silicon complex loaded in the carbon-based material, the silicon complex has a core-shell structure, the core-shell structure is composed of an inner core and an outer shell, the inner core is silicon nanoparticles, and the outer shell is silicon dioxide aerogel. The preparation method of the composite negative electrode material comprises the following steps: mixing a mixed solution containing nano silicon particles, a silicon source and a solvent to obtain composite sol; mixing the composite sol with a carbon source, and performing gel treatment to form a gel complex; carrying out aging and solvent replacement on the gel complex, and drying to form a silicon-carbon composite aerogel precursor; and carrying out carbonization treatment on the silicon-carbon comp