The invention discloses a preparation method of a
phosphorus /
silicon composite negative
electrode material, and belongs to the technical field of
lithium battery negative
electrode materials. The method comprises the following steps: putting
porous carbon into a CVD (
Chemical Vapor Deposition) furnace, vacuumizing, heating to 180-230 DEG C, and keeping the temperature for 50-70 minutes; the temperature is increased to 600-800 DEG C, SiH4
silane gas is introduced,
cracking deposition is carried out, and the deposition time is 2-3 h; cooling to 300-500 DEG C, introducing a
phosphorus source, and permeating into mesopores of 2-50 nm; and cooling the CVD furnace to 260-350 DEG C, and keeping the temperature for 24-72 hours, so that the simple substance is phosphatized into the amorphous red
phosphorus nanoparticles. Nanocrystallized phosphorus and
silicon are compounded into
porous carbon channels, and the characteristic that the lithiation potential of a phosphorus negative
electrode is high is utilized, so that the negative electrode is far away from the
lithium precipitation potential; meanwhile, the lithiation
gram volume of the phosphorus negative electrode is also very high, and the
gram volume of the material is not reduced.
Silicon is deposited firstly, then phosphorus is deposited, and the
silicon is deposited on the innermost side of a pore channel; and expansion in the phosphorus / silicon lithiation process is inhibited by utilizing the confinement of the
porous carbon, so that circulation is guaranteed.