Electricity from renewable energy sources is craving for efficient storage technologies, in particular solar industry, to enable practical small-scale solutions for residential and offices use. The best stationary technology is probably the redox flow batteries. This article proposes the direct conversion of sunlight into electrochemical energy stored in a redox flow battery. A photoelectrochemical cell is used to charge a vanadium redox flow cell (CdS(s)|V 3 + , VO 2 + ||V 3 + , V 2 + |Carbon

more »

... elt(s), E 0 =0.6 V NHE ). A CdS thin film photoelectrode is prepared to directly charge the cell, pairs V 3 + /VO 2 + . CdS photoanode exhibits competitive photocurrents, when compared to other photoelectrochemical devices, and yields enough photovoltage to charge the vanadium battery up to 75% with no external bias. An overlayer of CdSe improves the performance of CdS with current densities up to ca. 1.4 mA cm À 2 . Finally, a tandem configuration is tested using a dye-sensitized solar cell and a CdS photoanoade creating $ 1.3 V of photovoltage. This tandem arrangement proves to charge conventional all vanadium redox cell (DSC/CdS(s)|VO 2 + , VO 2 + ||V 3 + , V 2 + |Carbon Felt(s), E 0 =1.2 V NHE ) without external bias.