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Abstract
The integration of photovoltaic conversion and electrical energy storage in photoelectrochemical energy storage systems has emerged as a highly promising technological approach. Leveraging the excellent light absorption properties and catalytic activity of polythiophene, we designed and constructed a photo-assisted water-splitting secondary battery energy storage system. This system utilizes a polythiophene-integrated photoelectrode combined with photo-assisted zinc-air battery charging and photo-assisted zinc-proton battery discharging. During the charging process, the introduction of light energy significantly reduces the charging voltage in zinc-air batteries. Conversely, during the discharge process, light energy enhances the discharge platform of zinc-proton batteries. We also investigated the impact of different electrolyte compositions at the zinc anode on photovoltaic conversion efficiency and energy efficiency. When an alkaline electrolyte was used at the zinc anode, the energy efficiency of the photo-assisted water-splitting secondary battery reached 118.1%. With a saturated ZnCl₂ electrolyte, the overall energy efficiency increased to 125.4%. By employing a saturated ZnCl₂ electrolyte for charging and an alkaline electrolyte for discharging, the energy efficiency of the non-equilibrium photo-assisted water-splitting secondary battery reached 190%, offering new possibilities for energy storage regulation.
