Preparation of graphene-like carbon attached porous silicon anode by magnesiothermic and nickel-catalyzed reduction reactions

For improving performance of silicon anode in lithium ion batteries, a two-step preparation method was applied for synthesis of silicon carbon powder. The first step was to prepare Si/Ni composite powder by magnesiothermic reduction reaction in which Tetraethoxysilane (TEOS) was silicon source and NiCl2 center dot 6H(2)O was nickel source. The second step was to prepare silicon carbon in which triethylene glycol was carbon source and reduced by nickel catalyzed reactions on the surface of Si/Ni composite particles. Strawberry-like porous silicon attached with graphene-like carbon was found in the sample of Si-C powder treated by 1 M FeCl(3)and 5 wt.% HF. Charge/discharge performance of anode materials were measured in button cells. The highest discharge specific capacity of Si-C powder can reach to 1275 mAh g(-1), but the cycle performance was not as good as Si/Ni composite powder. At the 50(th)cycle, the discharge specific capacity of Si/Ni composite powders and Si-C powders were 415 mAh g(-1)and 395 mAh g(-1), respectively.