Metal Oxide Coated Porous Silicon Electrode Fabricated by Anodized Liquid Phase Depositions

Abstract

The titanium oxide/PSi nanocomposite was fablicated by liquid phase deposition (LPD) method with applying anodic potential. Results of SEM-EDX measurement showed that TiO2 deposited into the fine pore (ca. 7.4 nm) only when oxidized PSi surface was used as F- scavenger or PSi was anodized under the existence of titanium ions. TiO2/PSi nanocomposite was fabricated by anodization of PSi in H2TiF6 electrolyte under constant potential. As the amount of Ti maximized at 300 mV vs. Ag/AgCl, deposition process can be controlled by applied potential in this method. The charge/discharge capacities were measured about fabricated TiO2/PSi as lithium-ion battery anode. The improvement of the capacity was derived from the increase in PSi wettability by TiO2 deposition and activation of silicon in fine structure. In addition, TiO2/PSi fabricated by anodization kept higher capacity without rapid degradation, because of free from SiO2.