Improvement of cycle behavior of Si/Sn anode composite supported by stable Si–O–C skeleton

A Si/Sn/SiOC/graphite (SSSG) composite with high efficiency and long-term cycling stability was synthesized by a cost-effective and scalable method, including the processes of mechanical milling and pyrolysis. The composite was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectrometry (EDX). The electrochemical properties were investigated until the 25th cycle. As a result, the SSSG composite anode exhibits excellent long-term cycling stability and capacity. Such SSSG composite anode shows excellent cycling stability with a specific capacity of 568.2 mAh·g⁻¹ and ∼80 % capacity retention over 25 cycles at 0.3C rate. The reasons for good electrochemical characteristics are considered that the SiOC net with favorable chemical stability acts as a skeleton to support and segregate Si/Sn nanostructures, and the graphitic mixing in the composite is used as conductive material to enhance the electrical conductivity in this composite. The results suggest that the design of this new structure has the potential to provide a way for the other functional composite materials.