Dual yolk-shell structure of carbon and silica-coated silicon for high-performance lithium-ion batteries

Authors

L Y. Yang, Central South University
H Z. Li, Central South University
Jun Liu, Central South UniversityFollow
Ziqi Sun, University of WollongongFollow
S S. Tang, Central South University
M Lei, Beijing University of Posts and Telecommunications

RIS ID

101406

Publication Details

Yang, L. Y., Li, H. Z., Liu, J., Sun, Z. Q., Tang, S. S. & Lei, M. (2015). Dual yolk-shell structure of carbon and silica-coated silicon for high-performance lithium-ion batteries. Scientific Reports, 5 10908-1-10908-9.

Abstract

Silicon batteries have attracted much attention in recent years due to their high theoretical capacity, although a rapid capacity fade is normally observed, attributed mainly to volume expansion during lithiation. Here, we report for the first time successful synthesis of Si/void/SiO₂/void/C nanostructures. The synthesis strategy only involves selective etching of SiO₂ in Si/SiO₂/C structures with hydrofluoric acid solution. Compared with reported results, such novel structures include a hard SiO₂-coated layer, a conductive carbon-coated layer, and two internal void spaces. In the structures, the carbon can enhance conductivity, the SiO₂ layer has mechanically strong qualities, and the two internal void spaces can confine and accommodate volume expansion of silicon during lithiation. Therefore, these specially designed dual yolk-shell structures exhibit a stable and high capacity of 956mA hg^-1 after 430 cycles with capacity retention of 83%, while the capacity of Si/C core-shell structures rapidly decreases in the first ten cycles under the same experimental conditions. The novel dual yolk-shell structures developed for Si can also be extended to other battery materials that undergo large volume changes.