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 [E0 (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.

Transition metal ions regulated oxygen evolution reaction performance of Ni-based hydroxides hierarchical nanoarrays

“…Because of growing demands for energy and environmental concerns, advanced technologies are being sought for the production of inexpensive, sustainable, and carbon-neutral fuels12345. Water splitting is promising for the production of fuel from renewable but intermittent energy sources, such as wind and solar6.…”

Seawater-Mediated Solar-to-Sodium Conversion by Bismuth Vanadate Photoanode- Photovoltaic Tandem Cell: Solar Rechargeable Seawater Battery

“…In addition, the redox mediator (O 2 /H 2 O) of our system (pH-neutral natural seawater) (Li et al., 2017) is nature friendly compared with existing SRCs, such as I − /I 3− (light absorber—N179/TiO 2 , Yu et al., 2014; TiO 2 , Li et al., 2016b; Fe 2 O 3 , Nikiforidis et al., 2016) and VO 2 + /VO 2+ (light absorber—CdS/CdSe, Azevedo et al., 2016). Previous demonstrations of O 2 /H 2 O redox-based SRCs achieved modest potential savings, but TiO 2 (3.2–3.0 eV, J charge ∼0.01 mA/cm 2 ) (Kim et al., 2016a) and C 3 N 4 (2.7 eV, J charge ∼ 0.05 mA/cm 2 ) (Liu et al., 2016) cannot achieve such a high current density as we did with BiVO 4 (2.4 eV, J charge >1.0–3.0 mA/cm 2 ). Another important aspect of our BiVO 4 PE is transparency that other previous studies could not have (Li et al., 2017, Liu et al., 2016).…”

Photovoltage memory effect in a portable Faradaic junction solar rechargeable device

“…However, the generated electricity needs to be stored to balance the intermittence of solar irradiance. In previous studies, solar supercapacitors or solar batteries can address this problem by simultaneous conversion and storage of solar energy 5 – 13 , which are typically with three-electrode or four-electrode configuration by the integration of solar cells and energy storage units. Nevertheless, these devices suffer from complicated structures and high cost, which limit their applications in a large scale 14 , 15 .…”