PANI/BiVO4 photoanode drived Fe-Br solar redox flow battery system for efficient solar energy conversion and storage

The efficient integration of photovoltaic conversion and energy storage technologies is critical to overcoming constraints in solar energy utilization. Solar rechargeable flow batteries (SRFBs) integrate solar energy conversion and storage via photoelectrode-driven redox processes, enabling economically viable pathways for sustainable solar energy storage. However, SRFB development faces limitations of thermodynamic voltage ceilings imposed by photoelectrode/redox couple energy level mismatches and the long-term durability of photoelectrodes. In this study, a PANI/BiVO 4 (PBVO) photoelectrode was fabricated, effectively preventing direct contact between BiVO 4 (BVO) and the electrolyte, thereby suppressing the photocorrosion issues. Meanwhile, [Fe(CN) 6 ] 3- /[Fe(CN) 6 ] 4- and Br - /Br 3- (Fe-Br) redox pairs with high redox reversibility were used in the SRFB system. The designed PBVO Fe-Br SRFB achieved ultra-long stability and a sustained photocurrent for up to 50 h. Furthermore, the effectiveness of the charge transfer pathway in the PBVO electrode within the Fe-Br SRFB was verified, providing insights into the design of SRFBs.