Unravelling the practical solar charging performance limits of redox flow batteries based on a single photon device system

Abstract

In recent years, solar redox flow batteries have attracted attention as a possible integrated technology for simultaneous conversion and storage of solar energy. Unlike solar water splitting technologies which require at least 1.8V for meaningful performance, a lesson learned from previous solar redox flow battery (SRFB) studies is that even single-photon-devices can demonstrate unbiased photo-charging owing to the flexibility of redox couple selection. Thus, in this paper, we present the theoretical model reflecting experimental parameters, such that we can highlight important parameters that merit the most attention in further studies towards the practical development of SRFBs. Importantly, the results clearly show how to choose the optimum combination of semiconductor and redox couples under unavoidable limitations that a practical system would encounter, including, but not limited to optical loss by the electrolyte, overpotential, device architecture and chemical potentials.