Seawater-Mediated Solar-to-Sodium Conversion by Bismuth Vanadate Photoanode- Photovoltaic Tandem Cell: Solar Rechargeable Seawater Battery
Jin Hyun Kim,
Soo Min Hwang,
Inchan Hwang,
Jinhyup Han,
Jeong Hun Kim,
Yim Hyun Jo,
Kwanyong Seo,
Youngsik Kim,
Jae Sung Lee
Affiliations
Jin Hyun Kim
Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan 44919, Republic of Korea; Corresponding author
Soo Min Hwang
Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan 44919, Republic of Korea
Inchan Hwang
Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan 44919, Republic of Korea
Jinhyup Han
Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan 44919, Republic of Korea
Jeong Hun Kim
Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan 44919, Republic of Korea
Yim Hyun Jo
Advanced Center for Energy, Korea Institute of Energy Research (KIER), Ulsan 44919, Republic of Korea
Kwanyong Seo
Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan 44919, Republic of Korea
Youngsik Kim
Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan 44919, Republic of Korea; Energy Materials and Devices Lab, 4TOONE Corporation, 50 UNIST-gil, Ulsan 44919, Republic of Korea; Corresponding author
Jae Sung Lee
Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science & Technology (UNIST), Ulsan 44919, Republic of Korea; Corresponding author
Summary: Conversion of sunlight to chemical energy based on photoelectrochemical (PEC) processes has been considered as a promising strategy for solar energy harvesting. Here, we propose a novel platform that converts solar energy into sodium (Na) as a solid-state solar fuel via the PEC oxidation of natural seawater, for which a Na ion-selective ceramic membrane is employed together with photoelectrode (PE)-photovoltaic (PV) tandem cell. Using an elaborately modified bismuth vanadate-based PE in tandem with crystalline silicon PV, we demonstrate unassisted solar-to-Na conversion (equivalent to solar charge of seawater battery) with an unprecedentedly high efficiency of 8% (expected operating point under 1 sun) and measured operation efficiency of 5.7% (0.2 sun) and long-term stability, suggesting a new benchmark for low-cost, efficient, and scalable solid solar fuel production. The sodium turns easily into electricity on demand making the device a nature-friendly, monolithic solar rechargeable seawater battery. : Electrochemical Energy Conversion; Energy Storage; Materials Characterization Subject Areas: Electrochemical Energy Conversion, Energy Storage, Materials Characterization