Robust SiC coated C/SiOx composites for high-performance lithium storage

Abstract

Silicon-oxygen-carbon (C/SiO_x) composites show promising potential as anode materials for lithium-ion batteries due to their versatile synthesis methods, cost-effectiveness, and minimal volume expansion characteristics. However, persistent challenges such as poor cycle stability, conductivity issues, and low initial coulombic efficiency need to be addressed. In this research, a novel C/SiO_x@SiC composite is developed for lithium-ion battery anodes through a two-stage process involving thermal stirring and composite coating. The high-temperature phase transition of carbon and silicon leads to the formation of SiC, intertwining with C/SiO_x to effectively encase silicon particles. The resulting C/SiO_x@SiC material demonstrates outstanding charge and discharge coulombic efficiencies, reaching 98.3%, 98.7%, 99.0%, and 99.6% at current densities of 0.2, 0.5, 1, and 2 A g⁻¹, respectively, as well as excellent cycle stability, maintaining a stable capacity of 501.15 mAh·g⁻¹ after 500 charge-discharge cycles. This highlights the effectiveness of the stirring composite strategy and pitch-derived carbon coating technology in enhancing the overall performance of silicon-oxygen-carbon anodes. These advancements play a significant role in advancing the research and development of high-energy-density lithium-ion battery materials for next-generation applications.