Evaluation of Electrochemical Performance of Recovery Silicon from Waste Silicon Sludge As Lithium Ion Battery

Recently, in terms of Lithium ion battery market has been widely growing up from mobile IT devices into Electrical Vehicle market. The battery is the most important part in xEV than any other parts. Anode materials in lithium ion battery, those price evaluated about 10 % in composition of typical lithium ion battery. However, the price of anode parts including carbon or silicon materialss were very unstable. It absolutely relies on importation in korea. The silicon which has superior theoretical specific capacity than commercial anode materials (Si = 4200 mAh/g, Carbon = 372 mAh/g), To develop silicon based anode materials for lithium ion battery, raw material of silicon should be priceless and stable supply chain.

To figure out these unstable raw material market, we had been focused on waste silicon sludge which were gathered by process for silicon wafer back grinding. The waste silicon sludge were discarded over 2000 ton/year, all of them are currently buried in korea.

  Waste silicon sludge were consists of wafer grinding materials, silicon, and water/oils. Herein, we recovered the silicon from waste silicon sludge and purified the silicon for lithium ion battery anode starting materials. Not only recovred silicon, also recovery silicon had been pulverized to nano-sized by beads-milling. these nano-sized recovery silicon induced that shorten lithium ion paths and large surface area. Malic acid was a chosen media for carbon coating on nano-sized recovery silicon surface. We analyzed among recovered silicon properties and its electrochemical performance.