Controllable synthesis of spherical silicon and its performance as an anode for lithium-ion batteries

Spherical silicon is controllably synthesized by the hydrolysis of tetraethylorthosilicate (TEOS) with the addition of different contents of ammonia to form SiO2, then reduced by magnesium powder in argon atmosphere at 900 A degrees C for 3 h. The experimental results show that the electrochemical performance of the as-prepared silicon anode is much affected by the morphology of silicon, and the spherical silicon with a particle size of 250-300 nm shows a reversible capacity of 1,345.8 mAh g(-1) with the capacity retention of 83.2 % after 20 cycles. The relationship between the electrochemical performance of the spherical silicon and the diameters of silicon sphere makes it possible to control the performance of the silicon anode by adjusting the hydrolysis conditions of TEOS.