SiO/Carbon complex produced by carbothermal reduction for the anode materials of high-performance lithium ion battery.

Abstract

SiO/carbon complexes were prepared by electrospinning and carbothermal reduction to improve the rate performance at a high C rate, and their electrochemical properties were investigated for use as an anode material in a lithium ion battery. The SiO/carbon complexes that were prepared by electrospinning had a fibrous structure with considerable beads. The crystal structure, composition, and surface chemical composition of the SiO/carbon complexes changed based on the carbothermal reduction temperature. The SiO/carbon complexes were a mixture of SiO2, PAN-based carbon, and beta-SiC. SiC crystal structures and C--Si--O or Si--C bonds formed from the reaction of SiO2 and PAN in the SiO2/PAN complex during carbothermal reduction above 1,500 degrees C. The charge-discharge profiles of these SiO/carbon complexes were similar to those observed for disordered carbon. The second discharge capacities and rate capabilities of the SiO/carbon complexes were higher than those of graphite. These results were based on reversible lithium insertion into and extraction from a silicon material, such as amorphous SiO2 or Cx--Si--Oy.