Transforming silicon slag into high capacity anode material for lithium-ion batteries

A method for transforming silicon slag into an anode material in lithium-ion batteries, comprising applying mechanical grinding, such as high-energy ball milling, to reduce particle size of silicon slag to micron and submicron sizes and/or to increase the amorphicity of the silicon slag powder. The silicon slag being used as raw material in fabricating the anodes has a composition of Si-SiC-C-SiO2, preferably having Si phase in both crystalline and amorphous states, and more preferably having Si phase only in amorphous state after a high-energy ball-milling thereof. The silicon slag has preferably a median particle diameter ≤ 20 [mu]m after a high-energy ball-milling thereof and ≤ 20 [mu]m after a slurry homogenization thereof. The silicon slag preferably contains 64 %wt. Si + 31 %wt. SiC + 4 %wt. C + 1 %wt. SiO2.