Ball-Milling-Triggered Synthesis of Si/C/SiC@MCMB Composites from Carbon Dioxide for Improved Lithium Storage Capability

The excessive emission of carbon dioxide (CO2) poses a serious threat to the sustainable development of human beings. The efficient conversion of CO2 into high-value-added chemicals is of great significance for solving the greenhouse effect and energy crisis. Herein, a new strategy is proposed to turn CO2 into Si/C/SiC composites through a one-step ball-milling reaction with Mg2Si at room temperature. Moreover, mesophase carbon microspheres (MCMB) are introduced into reactants to prepare Si/C/SiC@MCMB composites for possible commercial application. This method realizes the synchronous formation of Si, C, and SiC with a tight interfacial contact at room temperature, which enhances the electronic conductivity and structural stability of Si/C. It is found that the addition of MCMB greatly restricts the formation of SiC inactive phase and leads to a thin lamellar structure for lithium storage. When evaluated as a lithium-ion battery anode, the Si/C/SiC@MCMB composites exhibit superior cycling stability and rating performance. This room temperature synthesis strategy has the advantages of low cost, simple operation process, and easy scalable production, which not only provide a new route to turn CO2 into a benefit but also provide a new way for the design and synthesis of high-capacity Si/C anodes.