Compact homogeneous Si/SiC/C in-situ nanocomposite microspheres as anode materials for lithium-ion batteries

Abstract

Compact homogeneous Si/SiC/C in-situ nanocomposite microspheres are synthesized by a procedure consisted of sol-gel, air calcination and magnesiothermic reduction processes. The components of Si, C, and SiC are all generated in situ and have the advantages of high dispersion and uniform distribution at the nanoscale level, which can maximize the conductivity and structural stability of nanocomposite microspheres when used as the anode materials for lithium-ion batteries. A series of samples with different compositions and morphologies are obtained by controlling the temperature in the air calcination step. Electrochemical tests reveal that the sample with the best comprehensive performance delivers an initial coulombic efficiency of 79.1 %, a reversible specific capacity of 1513 mAh g−1, and a capacity retention of 87.8 % after 200 cycles. The significantly enhanced electrochemical performance relative to the pure Si sample composed of irregular nanoparticles confirms that the method of synthesizing compact homogeneous materials through in-situ means is highly effective and promising for the fabrication of high-performance electrode materials.