In-situ construction of porous Si@C composites with LiCl template to provide silicon anode expansion buffer

Silicon-based anode material is one of the most promising alternative anodes for graphite due to its advantages of abundant reserves, environmental protection and high-energy-density. However, silicon still cannot be directly applied commercially as anode materials owing to the existences of huge volume change during the alloying and dealloying process. Herein, porous [email protected] composites are prepared by employment of nano silicon as the active substance particles, lithium chloride as the template and pitch powder as the carbon precursor. Results of electrochemical performance tests show that the cell based on the in-situ prepared porous [email protected] composites deliver a reversible good cycle stability. Besides, porous [email protected] composites show a lower thickness expansion rate of electrode (15.38%), compared with pure nano silicon (162.46%) and conventional [email protected] anodes (40.24%), respectively. It is believed that the improved performance is benefitted from the porous structure, which provides a buffer for the expansion of silicon, reduces the volume expansion of the electrode during the charge and discharge process, and thus inhibits the damage to the solid electrolyte interphase film outside the [email protected] composites. This work provides an environmentally friendly method to prepare porous [email protected] composite anode materials, which is suitable for large-scale preparation and industrialized production.