Preparation of micron-sized silicon monoxide (SiOx)@carbon nanotube (CNT)/polymethyl methacrylate (PMMA) composite capsules as Li-ion battery anodes via a novel pickering emulsion template method

Li-ion batteries (LIBs) with micron-sized silicon monoxide (SiOx) anodes are promising, ascribed to their favorable cost affordability and remarkable theoretical capacity, while the huge volume expansion and inferior Li+/e− conductivity of SiOx have severely restricted their further development. Herein, a micron-sized SiOx@carbon nanotube (CNT)/polymethyl methacrylate (PMMA) composite capsule is designed for advanced LIB anode via a novel Pickering emulsion template method. The volume variation of SiOx during (de)lithiation reactions is alleviated by the reserved space inside capsules, and the capsule shells of PMMA/CNT engage a significant Li+/e− conductivity as well. Besides, the activity of SiOx greatly remains due to the capsule protection and avoidance of high-temperature treatment. The experimental results indicate that the SiOx@CNT/PMMA composite anodes can present improved lithium storage abilities in aspects of capacity retention, rate performance, and coulombic efficiency. This proposed method hopes to provide a novel micron-scale structure design for Si-based anodes in LIBs.