A 25 cm(2) Solar Redox Flow Cell: Facing the Engineering Challenges of Upscaling

• Type: Article in International Scientific Journal
• Date: 2021-12-10

Authors

Dias, P. (Author) FEUP

Journal

Title: Advanced Energy Materials

Serial No. 12 No. 2102893

ISSN: 1614-6832

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 16 Citations

Scopus - 22 Citations

Other information

Authenticus ID: P-00V-V4G

DOI: 10.1002/aenm.202102893

Abstract (EN): The solar redox flow cell (SRFC) is an emerging technology that uses semiconductors to photocharge redox pairs, storing solar energy in electrochemical fuels and heat. Despite being in its infancy, significant efforts have been made in the development of high-efficient materials and in understanding the fundamental processes. However, little attention has been given to device architecture and scalability, which may prove equally important in bringing this technology closer to commercialization. This work is the first attempt at upscaling SRFCs, proposing an innovative 25 cm(2) photoactive-area device: the SolarFlow25 cell. A computational fluid dynamics model is developed to implement design key features aiming at: maximizing light absorption by the semiconductor, ensuring effective diffusion and convection of redox species, and guaranteeing minimal electronic and ionic transport resistances. After being connected to a redox flow cell (RFC), the combined SRFC/RFC device is used to photocharge-discharge a ferrocyanide/anthraquinone (2,7-AQDS) chemistry continuously. A nanostructured hematite (alpha-Fe2O3) photoelectrode combined in series with a dye-sensitized solar cell (DSSC) produces an unbiased photocurrent of approximate to 40 mA. The solar-to-output-electricity-efficiency remains stable at approximate to 0.44%, fourfold higher than any other reported hematite-driven SRFC. The guidelines provided here are expected to help design and upscale future SRFC devices, making solar energy accessible in decentralized locations.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 17