An efficient and economical route for the synthesis of porous two-dimensional (2D) nanoplates of silicon is developed via the magnesiothermically-induced phase transition of exfoliated clay 2D nanosheets. The magnesiothermic reaction of precursor clay nanosheets prepared by the exfoliation and restacking with Mg2+ cations yields porous 2D nanoplates of elemental silicon. The variation in the Mg:SiO2 ratio has a significant effect on the porosity and connectivity of silicon nanoplates. The porous silicon nanoplates show a high discharge capacity of 2000 mAh g-1 after 50 cycles. Of prime importance is that this electrode material still retains a large discharge capacity at higher C-rates, which is unusual for the elemental silicon electrode. This is mainly attributed to the improved diffusion of lithium ions, charge-transfer kinetics, and the preservation of the electrical connection of the porous 2D plate-shaped morphology. This study highlights the usefulness of clay mineral as an economical and scalable precursor of high-performance silicon electrodes with tailorable nanostructures.
Bibliographical noteFunding Information:
This study was supported by Solvay, the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (No. NRF-2014R1A2A1A10052809 ) and the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (NRF-2010-C1AAA001-2010-0029065).
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All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)