Advances and Challenges in Photoelectrochemical Redox Batteries for Solar Energy Conversion and Storage

The photoelectrochemical redox battery (PRB) has been regarded as an alternative candidate for large-scale solar energy capture, conversion, and storage as it combines the superior advantages of photoelectrochemical devices and redox batteries. As an emerging solar energy utilization technology, significant progress has been made towards promoting and proliferating the practical applications of PRBs. However, wide market penetration of PRBs is still being significantly inhibited by limited photocatalytic activity, low efficiency, among other critical issues. Furthermore, the integration of each component, including solar materials, redox couples, and membranes and their interaction in PRBs play vital roles towards achieving smooth operation and high performance. Herein, the materials, mechanisms, recent advances, and challenges in the use of PRBs are presented. The crucial influence of redox couples, photoelectrode materials, membranes on the performance of the system including how they affect solar energy capture, reaction kinetics, and internal losses are systematically discussed. In addition, the recent advances of a single-battery of photoelectrode mode and an integrated device of solar cell mode are summarized. Furthermore, the state of the art performance of PRBs and their upscaling progress are also discussed. Finally, the challenges and perspectives for the future development of PRBs are highlighted.