Lithium Photo-intercalation of CdS-Sensitized WO Anode for Energy Storage and Photoelectrochromic Applications.

Integration of solar-energy harvesting and storage functions has attracted significant research attention, as it holds promise for ultimate development of light-chargeable devices. In this context, a functional nanocomposite anode that not only permits electrochemical energy storage through Li-ion photo-intercalation, but also exhibits potential for photoelectrochromic applications, was investigated. The nanocomposite is made of the Li-ion intercalation compound WO , thinly coated with TiO and sensitized by the photoactive semiconductor CdS. During light exposure, the photoelectrons from CdS are transported to the WO /electrolyte interface, where Li-ion intercalation takes place. Photoelectron transport is facilitated by the interfacial TiO layer. The WO was shown to be functional in multiple photocharge-discharge cycles, but the CdS suffers from degradation and photocorrosion. Hence, the selection of compatible semiconductors and protective coating strategies should be pursued to overcome these issues.