On-site fabrication and charge–discharge property of TiO2 coated porous silicon electrode by the liquid phase deposition with anodic oxidation

• TiO2/porous Si (PSi) nanocomposites were fabricated by liquid-phase deposition with anodization of PSi.
• Improvements in the charge/discharge capacity were achieved by TiO2 deposition.
• TiO2/PSi fabricated by anodization maintained a high charge/discharge capacity as lithium ion battery without rapid degradation.

TiO2/porous Si (PSi) nanocomposites were fabricated by liquid-phase deposition with anodization of PSi. Scanning electron microscopy-energy-dispersive X-ray spectroscopy showed that TiO2 was only deposited in the fine pores of anodized PSi (ca. 7.4 nm) when the PSi surface was anodized in the presence of Ti ions as F− scavengers. The TiO2/PSi nanocomposites were fabricated by anodization of PSi in a H2TiF6 electrolyte at a constant potential. The amount of Ti deposited was maximum at 300 mV vs. Ag/AgCl electrode, and the deposition process was controlled by varying the applied potential for PSi anodization. The charge/discharge capacities of the fabricated TiO2/PSi nanocomposites as Li-ion battery anodes were determined. Improvements in the charge/discharge capacity were achieved by improving the PSi wettability by TiO2 deposition and activation of Si on the surface of the anodized PSi fine pores. TiO2/PSi fabricated by anodization maintained a high charge/discharge capacity without rapid degradation, because SiO2, which causes rapid degradation of the charge/discharge capacity, was reduced by Li metal.

TiO2/porous Si (PSi) nanocomposites were fabricated by liquid-phase deposition with anodization of PSi. Improvements in the charge/discharge capacity were achieved by improving the PSi wettability by TiO2 deposition and activation of Si on the surface of the anodized PSi fine pores. TiO2/PSi fabricated by anodization maintained a high charge/discharge capacity as lithium ion battery without rapid degradation.Figure optionsDownload as PowerPoint slide