Scalable silicon@sulfur-doped carbon composites via a low-cost facile method for high-performance lithium-ion battery anodes

The development of facile and low-cost fabrication methods for silicon/carbon (Si/C) composites with stable cycle performance is urgent requirement for the development of high-energy-density lithium-ion batteries. Exploring carbon materials with good mechanical properties and electrochemical stability for the fabrication of Si/C materials can overcome the extreme volume changes and unstable electrochemical stability of Si anodes. Herein, silicon@sulfur-doped carbon (Si@S-C) composites were successfully synthesized by simple solvent evaporation and carbonization of inexpensive and readily available petroleum pitch (PP) and amorphous sulfur. Various sulfur-containing functional groups enhanced the material strength of composite by increasing the chemical crosslinking of the carbon matrix to adapt to the Si volume changes. In addition, the larger carbon layer spacing and defects derived from sulfur doping can promote Li + diffusion and electrode reaction. As a result, the optimized Si@S-C142 exhibited stable interfacial electrode stability and moderate cycle performance, delivering a specific capacity of 681.6 mAh·g −1 and 79.1% capacity retention at 0.5 A g −1 after 700 cycles. This synthesis strategy for Si@S-C composites is meaningful for scalable and low-cost fabrication as well as for understanding the effect of sulfur-doped carbon in Si/C anodes.