Abstract: Porous Si from rectorite as raw materials was prepared with magnesiothermic reduction and then Si/C composite as anode materials was prepared by high-heat treatment of the carbon coating with glucose as carbon precursor in a nitrogenous atmosphere. The influences of magnesiothermic condition on structures of the samples were characterized by X-ray diffraction（XRD），nitrogen absorption and desorption（BET）， scanning electron microscope （SEM）and thermogravimetric analysis（TG）. The electrochemical performances of the Si/C anode material were investigated by an electrochemical workstation and a battery charge-discharge test system. The results shows that the pore volume，average pore diameter and silicon content of the porous silicon from rectorite with magnesiothermic reduction had important influences on the electrochemical performance of the Si/C composite. The electrochemical performances of the Si/C anode material increased first and then decreased while the magnesium powder dosage was increased in the magnesiothermic reduction. When the mass ratio of rectorite to magnesium was 1∶0. 4，the Si/C composite had the highest electrochemical performances. The sample maintained the reversible capacity of 1120 mAh/g after the first cycle and it still maintained 555 mAh/g after 200 charge-discharge cycles at a current density of 0. 1 A/g.

Key words: rectorite, magnesiothermic reduction, Si/C composite material, electrochemical performance