The invention provides a
silicon-based
composite material, which is prepared from
silicon particles,
silicate and optional carbon, wherein the mixture of the
silicate and the optional carbon forms a massive body, and the
silicon particles are dispersed in the massive body. A preparation method comprises the following steps of: dispersing the silicon particles into absolute ethyl
alcohol and / or deionized water to form suspension liquid; dispersing the
silicate and the optional carbon into the absolute ethyl
alcohol and / or the deionized water to form suspension liquid; ultrasonically oscillating the two kinds of suspension liquid respectively, and then stirring; dropwise adding the suspension liquid of the silicon particles into the suspension liquid of the silicate and the optional carbon to form mixed liquid, heating and stirring the mixed liquid until evaporating the mixed liquid into paste; then, putting the paste in an oven to be dried to obtain masses, and
grinding and sieving to obtain undersize particles; and conducting heat treatment in an
inert atmosphere, and
grinding and sieving to obtain the silicon-based
composite material. According to the silicon-based
composite material, a lattice structure of the silicon particles can be ensured, therefore the activity of the silicon particles is ensured, and the
energy density, the first-time
coulomb efficiency and the high-temperature storage performance of
lithium ion batteries are increased.