title: Solar-rechargeable battery based on photoelectrochemical water oxidation: Solar water battery.
abstract: As an alternative to the photoelectrochemical water splitting for use in the fuel cells used to generate electrical power, this study set out to develop a solar energy rechargeable battery system based on photoelectrochemical water oxidation. We refer to this design as a "solar water battery". The solar water battery integrates a photoelectrochemical cell and battery into a single device. It uses a water oxidation reaction to simultaneously convert and store solar energy. With the solar water battery, light striking the photoelectrode causes the water to be photo-oxidized, thus charging the battery. During the discharge process, the solar water battery reduces oxygen to water with a high coulombic efficiency (>90%) and a high average output voltage (0.6 V). Because the reduction potential of oxygen is more positive [E(0) (O2/H2O) = 1.23 V vs. NHE] than common catholytes (e.g., iodide, sulfur), a high discharge voltage is produced. The solar water battery also exhibits a superior storage ability, maintaining 99% of its specific discharge capacitance after 10 h of storage, without any evidence of self-discharge. The optimization of the cell design and configuration, taking the presence of oxygen in the cell into account, was critical to achieving an efficient photocharge/discharge.
authors.affiliation: Division of Nano and Energy Convergence Research, Deagu Gyeongbuk Institute of Science &Technology (DGIST), 333, Techno Jungang Daero, Hyeonpung-myeon, Dalseong-gun, Daegu 42988, Korea.
authors.forename: Gonu
authors.initials: G
authors.lastname: Kim
authors.affiliation: Division of Nano and Energy Convergence Research, Deagu Gyeongbuk Institute of Science &Technology (DGIST), 333, Techno Jungang Daero, Hyeonpung-myeon, Dalseong-gun, Daegu 42988, Korea.
authors.forename: Misol
authors.initials: M
authors.lastname: Oh
authors.affiliation: Division of Nano and Energy Convergence Research, Deagu Gyeongbuk Institute of Science &Technology (DGIST), 333, Techno Jungang Daero, Hyeonpung-myeon, Dalseong-gun, Daegu 42988, Korea.
authors.forename: Yiseul
authors.initials: Y
authors.lastname: Park