An Approach to Solar Rechargeable Flow Battery Based on Electroactive Organic Redox Couples

An integrated photo-electrochemical solar energy conversion and storage device is developed by a dye sensitized TiO2 solar cells and 2, 2, 6, 6-tetramethyl-1-piperidinyloxy (TEMPO) / 1, 4- Benzoquinone (BQ) redox flow batteries. The device can be directly charged by solar light without external bias, and discharged like normal RFBs with an energy storage density of 3.5 mAhg-1 over many cycles. The proposed device demonstrates a rapid photo-charge at light illumination and a stable electrochemical discharge in the dark, realizing an in situ photo-to-chemical-to-electrical conversion and photo-to-chemical storage.