This paper reports unique highly porous carbon-coated Si nanoparticles with canyon-like surfaces (cpSi@C) prepared by pseudomorphic transformation of wrinkled silica nanoparticles (WSNs) via magnesiothermic reduction and subsequent pyrolytic deposition of carbon. The pseudomorphic transformation of soft-template-based WSNs with large pore dimensions provides Si nanoparticles with additional porosity owing to their unique canyon-like surface structure. This degree of porosity is not achievable using conventional soft-template-derived porous SiO2 materials owing to their smaller pore dimensions. The free volume space in the cpSi@C particles is 419% of their Si volume, which is sufficient to fully accommodate Si volume expansion during cycling. Furthermore, the conformal carbon coating allows cpSi@C to enhance its electrical conductivity. cpSi@C exhibits a high specific charge capacity of 822 mA h g-1 after 200 cycles at a current density of 0.5 A g-1, which is 59.1% of the initial charge capacity. A comparative study with respect to other porous Si-based materials clearly revealed that the unique canyon-like structure synthesized in this study, with its additional pore volume and smaller Si dimensions, exhibits enhanced electrochemical performance.
Bibliographical noteFunding Information:
This work was nancially supported by the National Research Foundation of Korea (NRF) (grant no. 2012R1A3A2026417) funded by the Korean government (MSIP).
© 2018 The Royal Society of Chemistry.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)