Boosting Energy Storage in Metal Batteries by Light: Progress, Challenges, and Perspectives

Metal batteries with high theoretical capacities have become more important than ever in pursuing carbon-neutral initiatives to reduce fossil energy consumption and incorporate intermittent renewable energy into the electric grid. However, cathode materials often encounter significant challenges, such as sluggish reaction kinetics, limited capacities, or low operation voltages, limiting the practical applications of these batteries. Inspired by light-matter interactions that might provoke a photoelectric or photothermal effect on light-responsive materials, various light-responsive batteries have been developed by introducing photoactive materials to convert solar energy into electrical (or thermal) energy, addressing the issues facing cathode materials. Despite the fact that some reviews have been published to summarize the advances in light-responsive batteries with the rapid development of the rising field, the basic working principles of light-responsive batteries are still not well elucidated in detail. In this review, we first give a summary of the understanding of the photoelectric and photothermal effects and correlate their parameters with the metrics (voltage, capacity, and kinetics) of light-responsive batteries. Then, we provide representative examples of light-responsive batteries to support the understanding. Finally, the challenges in the development of light-responsive metal batteries are discussed. Accordingly, potential directions and key perspectives for light-responsive metal batteries are also proposed in the hope of guiding their design and optimization for accelerating practical application.