Low-expansion silicon-carbon negative electrode material and preparation method thereof

The invention discloses a low-expansion silicon-carbon negative electrode material and a preparation method thereof, and mainly relates to the field of lithium ion batteries. Comprising silicon-carbon particles, and the silicon-carbon particles comprise composite particles of a porous material and a nanoscale silicon-based material, a carbon coating layer, graphite and organic matter cracked carbon; the structure of the composite particle of the porous material and the nanoscale silicon-based material is that a silicon layer of the nanoscale silicon-based material is deposited in holes of the porous material. The preparation method has the beneficial effects that a nano composite structure formed by cracking and depositing a silicon source in a porous material is adopted, the capacity is high, only part of a silicon layer is deposited in pores, and an expansion space is provided for the circulation process of a nanoscale silicon-based material, so that the silicon-carbon negative electrode material is small i