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

Abstract

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∙6H2O 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 FeCl3 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 50th 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.