Controllable Synthesis of Carbon-Coated SiOx Particles through a Simultaneous Reaction between the Hydrolysis-Condensation of Tetramethyl Orthosilicate and the Polymerization of 3-Aminophenol.

ABSTRACT

Core-shell particles are desirable for many applications, but the precise design and control of their structure remains a great challenge. In this work, we developed a strategy to fabricate carbon-coated SiOx (SiOx@C) core-shell particles via a sol-gel method using the simultaneous hydrolysis-condensation of tetramethyl orthosilicate (TMOS), the polymerization of 3-aminophenol and formaldehyde in the presence of ammonia as a basic catalyst, and cetyltrimethylammonium bromide (CTAB) as a cationic surfactant in the mixed solution of water and methanol followed by the carbonization process. Results from this study provide new insight into the design of core-shell particles by using TMOS as an effective silica precursor for the first time with a well-controlled reaction rate and spherical morphology. To obtain an in-depth understanding of the formation of core-shell structure, a possible mechanism is also proposed in this article. When tested as an anode material for lithium ion batteries (LIBs), the obtained SiOx@C particles delivered a reversible capacity of 509.2 mAh g-1 at a current density of 100 mA g-1. This electrochemical performance is significantly better than those of similar composites without the core-shell structure. The capacity retention after 100 cycles was approximately 80%. These results suggest great promise for the proposed SiOx@C particles with core-shell structure, which may have potential applications in the improvement of various energy-storage materials.