광전기화학적 태양에너지 전환/저장 시스템 (Solar water battery)의 최적화

Abstract

The solar water battery is an eco-friendly and efficient system that combines the advantages of a water oxidation-based photoelectrochemical cell and a solar-powered electrochemical energy storage system that can convert and store energy simultaneously. The battery, which consists of a photoelectrode, a storage electrode and a counter electrode, stores electrons generated through water oxidation by sunlight without additional external voltage. Thus, their properties and combination are important for the performance and efficiency of the solar water battery. In this study, each constituent of the solar water battery was optimized by the proper selection of materials. Firstly, the Pt foil was chosen as a counter electrode by virtue of its large area. Secondly, the TiO2 photoelectrode was compared to CdS and BiVO4 in terms of the position of their conduction band. Thirdly, PB was chosen as storage electrode material because it has a larger specific capacitance compared to WO3. As a result, the optimized composition (TiO2: NaFe-PB: Pt foil) exhibited 72.393 mAh/g of discharge capacitance after 15hr of photocharging. It indicates that the efficiency of solar energy conversion and storage is largely affected by the configuration of system.